@import url('studymate-tokens.css');

/* Main Content */
        .main-content {
            flex: 1;
            display: flex;
            gap: 1.5rem;
            padding: 1.5rem;
            overflow: hidden;
            min-height: 0;
        }
        
        .main-content::-webkit-scrollbar {
            width: 8px;
        }
        
        .main-content::-webkit-scrollbar-track {
            background: rgba(255, 255, 255, 0.05);
        }
        
        .main-content::-webkit-scrollbar-thumb {
            background: rgba(255, 255, 255, 0.2);
            border-radius: 10px;
        }
        
        .main-content::-webkit-scrollbar-thumb:hover {
            background: rgba(255, 255, 255, 0.3);
        }

        /* Chat Selector Sidebar */
        .chat-selector {
            flex: 0 0 280px;
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            border-radius: 20px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            display: flex;
            flex-direction: column;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            overflow: hidden;
            transition: transform 0.3s ease, opacity 0.3s ease;
        }

        .chat-selector.hidden {
            transform: translateX(-100%);
            opacity: 0;
            width: 0;
            flex: 0;
            margin: 0;
            padding: 0;
            overflow: hidden;
        }

        .chat-selector-header {
            padding: 1.5rem;
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
            color: #ffffff;
            font-weight: 600;
            font-size: 1.1rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
            gap: 0.5rem;
        }

        .chat-search-container {
            padding: 0.75rem 1rem;
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        }

        .chat-search-input {
            width: 100%;
            padding: 0.6rem 1rem;
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 20px;
            background: rgba(255, 255, 255, 0.1);
            color: #ffffff;
            font-size: 0.85rem;
            outline: none;
            transition: all 0.3s ease;
        }

        .chat-search-input::placeholder {
            color: rgba(255, 255, 255, 0.5);
        }

        .chat-search-input:focus {
            border-color: rgba(255, 255, 255, 0.4);
            background: rgba(255, 255, 255, 0.15);
        }

        .chat-item.hidden {
            display: none;
        }

        .chat-item .highlight {
            background: rgba(255, 217, 61, 0.3);
            border-radius: 2px;
            padding: 0 2px;
        }

        .classes-panel {
            flex-shrink: 0;
            padding: 0.65rem 0.75rem 0.5rem;
            border-bottom: 1px solid rgba(255, 255, 255, 0.12);
            background: rgba(0, 0, 0, 0.12);
        }
        .classes-empty {
            font-size: 0.8rem;
            color: rgba(255, 255, 255, 0.55);
            line-height: 1.45;
            padding: 0.35rem 0.25rem 0.5rem;
        }
        .chat-selector.institutional-mode .chat-selector-header span#sidebar-header-label {
            font-size: 1rem;
            letter-spacing: 0.02em;
        }
        .classes-panel-row {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 0.5rem;
            margin-bottom: 0.35rem;
            padding: 0 0.25rem;
        }
        .classes-panel-title {
            font-size: 0.72rem;
            font-weight: 600;
            letter-spacing: 0.04em;
            text-transform: uppercase;
            color: rgba(255, 255, 255, 0.45);
        }
        .class-clear-btn {
            background: none;
            border: none;
            color: rgba(167, 139, 250, 0.9);
            font-size: 0.72rem;
            font-weight: 500;
            cursor: pointer;
            padding: 0.15rem 0.25rem;
            font-family: inherit;
        }
        .class-clear-btn:hover {
            color: #e9d5ff;
            text-decoration: underline;
        }
        .sidebar-scroll {
            flex: 1;
            min-height: 0;
            overflow-y: auto;
            display: flex;
            flex-direction: column;
        }
        .classes-list-ui {
            display: flex;
            flex-direction: column;
            gap: 0.05rem;
            padding: 0 0.35rem 0.25rem;
        }
        .class-project {
            margin: 0;
        }
        .class-project-header {
            display: flex;
            align-items: center;
            gap: 0.35rem;
            width: 100%;
            text-align: left;
            padding: 0.38rem 0.45rem;
            margin: 0;
            border: none;
            border-radius: 8px;
            background: transparent;
            color: rgba(255, 255, 255, 0.9);
            font-size: 0.84rem;
            font-weight: 600;
            line-height: 1.3;
            cursor: pointer;
            transition: background 0.12s ease;
            font-family: inherit;
        }
        .class-project-header:hover {
            background: rgba(255, 255, 255, 0.08);
        }
        .class-project-header.active {
            background: rgba(139, 92, 246, 0.22);
        }
        .class-chevron {
            flex-shrink: 0;
            width: 0.85rem;
            color: rgba(255, 255, 255, 0.45);
            font-size: 0.7rem;
        }
        .class-project-name {
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
        }
        .class-project-chats {
            display: flex;
            flex-direction: column;
            gap: 0.15rem;
            padding: 0 0 0.2rem 0.15rem;
        }
        .chat-item.class-nested-chat {
            padding: 0.45rem 0.55rem 0.45rem 1.35rem;
            margin-left: 0.35rem;
            border-radius: 8px;
            font-size: 0.82rem;
            background: rgba(255, 255, 255, 0.03);
        }
        .chat-item.class-nested-chat .chat-item-title {
            font-size: 0.82rem;
            font-weight: 500;
        }
        .chat-item.class-nested-chat:hover {
            transform: none;
        }
        .chat-selector.institutional-mode .chat-list {
            padding-top: 0.35rem;
        }
        .chat-selector.institutional-mode .chat-item {
            padding: 0.55rem 0.75rem;
        }
        .sidebar-section-label {
            flex-shrink: 0;
            padding: 0.65rem 1rem 0.35rem;
            font-size: 0.72rem;
            font-weight: 600;
            letter-spacing: 0.04em;
            text-transform: uppercase;
            color: rgba(255, 255, 255, 0.45);
        }
        .sidebar-section-label.hidden {
            display: none;
        }
        .academic-profile-banner {
            flex-shrink: 0;
            margin: 0.5rem 0.75rem 0;
            padding: 0.65rem 0.75rem;
            border-radius: 10px;
            background: rgba(139, 92, 246, 0.15);
            border: 1px solid rgba(139, 92, 246, 0.25);
            font-size: 0.8rem;
            line-height: 1.45;
            color: rgba(255, 255, 255, 0.9);
            display: none;
        }
        .academic-profile-banner strong {
            color: #e9d5ff;
        }
        .class-context-badge {
            display: inline-block;
            margin-left: 8px;
            padding: 2px 8px;
            border-radius: 999px;
            font-size: 0.72rem;
            background: rgba(139, 92, 246, 0.35);
            color: #e9d5ff;
            vertical-align: middle;
        }

        .new-chat-btn {
            width: 35px;
            height: 35px;
            border-radius: 50%;
            background: linear-gradient(135deg, #ff6b6b, #4ecdc4);
            border: none;
            color: white;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
            font-size: 1.2rem;
            font-weight: bold;
        }

        .new-chat-btn:hover {
            transform: scale(1.1);
            box-shadow: 0 6px 25px rgba(0, 0, 0, 0.3);
        }

        .chat-list {
            flex: 0 0 auto;
            overflow: visible;
            padding: 1rem;
            display: flex;
            flex-direction: column;
            gap: 0.5rem;
        }

        .chat-item {
            padding: 1rem 1.25rem;
            border-radius: 12px;
            background: rgba(255, 255, 255, 0.05);
            border: 1px solid rgba(255, 255, 255, 0.1);
            cursor: pointer;
            transition: all 0.3s ease;
            color: #ffffff;
            display: flex;
            justify-content: space-between;
            align-items: center;
            gap: 0.5rem;
            position: relative;
        }

        .chat-item:hover {
            background: rgba(255, 255, 255, 0.15);
            transform: translateX(5px);
            border-color: rgba(255, 255, 255, 0.3);
        }
        
        .chat-item:hover .delete-chat-btn {
            opacity: 1;
        }

        .chat-item.active {
            background: rgba(255, 255, 255, 0.2);
            border-color: rgba(255, 255, 255, 0.4);
            box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
        }

        .chat-item-title {
            font-weight: 600;
            font-size: 0.95rem;
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
            flex: 1;
        }
        
        .delete-chat-btn {
            background: rgba(255, 107, 107, 0.8);
            border: none;
            color: white;
            width: 28px;
            height: 28px;
            border-radius: 50%;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1rem;
            transition: all 0.3s ease;
            /* Always visible so the affordance is discoverable. Hover
               on the row still drives it to full opacity (.chat-item:hover
               rule below). */
            opacity: 0.65;
            flex-shrink: 0;
        }
        
        .delete-chat-btn:hover {
            background: rgba(255, 107, 107, 1);
            transform: scale(1.1);
            box-shadow: 0 4px 15px rgba(255, 107, 107, 0.5);
        }
        
        .delete-chat-btn:active {
            transform: scale(0.95);
        }

        /* Toggle Sidebar Button (top nav — never overlaps sidebar content) */
        .top-nav .toggle-sidebar-btn {
            position: static;
            transform: none;
            flex-shrink: 0;
            width: 38px;
            height: 38px;
            border-radius: 10px;
            background: rgba(255, 255, 255, 0.12);
            border: 1px solid rgba(255, 255, 255, 0.22);
            color: white;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: background 0.2s ease, transform 0.2s ease;
            box-shadow: none;
            font-size: 1.1rem;
            z-index: auto;
        }

        .top-nav .toggle-sidebar-btn:hover {
            transform: scale(1.05);
            background: rgba(255, 255, 255, 0.2);
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
        }

        /* Chat Area */
        .chat-container {
            flex: 2;
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            border-radius: 20px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            display: flex;
            flex-direction: column;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            overflow: hidden;
            min-height: 0;
        }

        .chat-header {
            padding: 1.5rem;
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
            color: #ffffff;
            font-weight: 600;
            font-size: 1.1rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .chat-header-title {
            flex: 1;
        }

        .chat-header-actions {
            display: flex;
            gap: 0.5rem;
        }

        .export-btn {
            padding: 0.5rem 1rem;
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 20px;
            color: white;
            font-size: 0.8rem;
            cursor: pointer;
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            gap: 0.3rem;
        }

        .export-btn:hover {
            background: rgba(255, 255, 255, 0.2);
        }

        /* Advanced Reasoning Toggle */
        .advanced-reasoning-toggle,
        .step-by-step-toggle {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            padding: 0.5rem 1rem;
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 20px;
            color: white;
            font-size: 0.8rem;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .advanced-reasoning-toggle:hover,
        .step-by-step-toggle:hover {
            background: rgba(255, 255, 255, 0.15);
        }

        .advanced-reasoning-toggle.active {
            background: rgba(102, 126, 234, 0.3);
            border-color: rgba(102, 126, 234, 0.5);
        }

        .step-by-step-toggle.active {
            background: rgba(72, 187, 120, 0.3);
            border-color: rgba(72, 187, 120, 0.6);
        }

        .step-by-step-toggle.active .toggle-switch {
            background: rgba(72, 187, 120, 0.8);
        }

        /* Entitlements chip (remaining Advanced / Step-by-step counts).
           Intentionally NEVER shows AI-description remaining — the product
           spec requires that to stay invisible. */
        .entitlements-chip {
            padding: 0.5rem 1rem;
            background: rgba(255, 255, 255, 0.08);
            border: 1px solid rgba(255, 255, 255, 0.15);
            border-radius: 20px;
            color: white;
            font-size: 0.75rem;
            font-weight: 500;
            letter-spacing: 0.02em;
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            user-select: none;
        }
        .entitlements-chip .badge-owner {
            background: linear-gradient(135deg, #f59e0b, #f97316);
            padding: 2px 8px;
            border-radius: 10px;
            color: white;
            font-weight: 700;
            font-size: 0.7rem;
        }
        .entitlements-chip .badge-inst {
            background: rgba(59, 130, 246, 0.25);
            border: 1px solid rgba(59, 130, 246, 0.45);
            padding: 2px 8px;
            border-radius: 10px;
            font-weight: 600;
            font-size: 0.7rem;
        }
        .entitlements-chip a {
            color: #a7f3d0;
            text-decoration: none;
            font-weight: 600;
        }
        .entitlements-chip a:hover { text-decoration: underline; }

        /* Quota-exceeded modal */
        .sm-quota-overlay {
            position: fixed; inset: 0;
            background: rgba(15, 23, 42, 0.6);
            backdrop-filter: blur(4px);
            display: none;
            align-items: center; justify-content: center;
            z-index: 10000;
        }
        .sm-quota-overlay.open { display: flex; }
        .sm-quota-card {
            background: #1e1b4b;
            border: 1px solid rgba(255,255,255,0.14);
            border-radius: 16px;
            padding: 28px;
            max-width: 420px;
            color: white;
            text-align: center;
            box-shadow: 0 20px 50px rgba(0,0,0,0.5);
        }
        .sm-quota-card h3 { margin-bottom: 10px; font-size: 1.25rem; }
        .sm-quota-card p  { color: #cbd5e1; font-size: 0.95rem; margin-bottom: 20px; }
        .sm-quota-actions { display: flex; gap: 10px; justify-content: center; }
        .sm-quota-btn {
            padding: 10px 18px;
            border-radius: 10px;
            border: 1px solid rgba(255,255,255,0.18);
            background: rgba(255,255,255,0.08);
            color: white;
            cursor: pointer;
            font: inherit;
            font-weight: 600;
        }
        .sm-quota-btn.primary {
            background: linear-gradient(135deg, #8b5cf6, #a855f7);
            border-color: transparent;
        }

        /* Step-by-Step action buttons (✅ / ❌) under AI messages */
        .sbs-actions {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            margin-top: 0.75rem;
            align-items: center;
        }

        .sbs-btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            min-height: 36px;
            padding: 0 0.85rem;
            border-radius: 18px;
            font-size: 0.85rem;
            font-weight: 500;
            line-height: 1;
            cursor: pointer;
            border: 1px solid rgba(255, 255, 255, 0.25);
            background: rgba(255, 255, 255, 0.08);
            color: white;
            transition: transform 0.15s ease, background 0.2s ease, border-color 0.2s ease;
            user-select: none;
            white-space: nowrap;
        }

        .sbs-btn:hover {
            background: rgba(255, 255, 255, 0.18);
            transform: translateY(-1px);
        }

        .sbs-btn:active {
            transform: translateY(0);
        }

        .sbs-btn.continue:hover {
            border-color: rgba(72, 187, 120, 0.6);
            background: rgba(72, 187, 120, 0.18);
        }

        .sbs-btn.simplify:hover {
            border-color: rgba(237, 137, 54, 0.6);
            background: rgba(237, 137, 54, 0.18);
        }

        .sbs-btn:disabled {
            opacity: 0.4;
            cursor: not-allowed;
            transform: none;
        }

        /* Post-completion / "what next?" buttons. Rendered when the
           Step-by-Step flow is finished (final answer reached, fully closed,
           or optional concept extension). They send a follow-up PROMPT, not
           a chunk-advance signal. */
        .sbs-actions.sbs-actions--post {
            flex-wrap: wrap;
            gap: 0.5rem;
        }

        .sbs-followup-btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            height: 36px;
            padding: 0 0.9rem;
            border-radius: 18px;
            font-size: 0.85rem;
            font-weight: 500;
            line-height: 1;
            cursor: pointer;
            border: 1px solid rgba(102, 126, 234, 0.45);
            background: rgba(102, 126, 234, 0.18);
            color: white;
            transition: transform 0.15s ease, background 0.2s ease, border-color 0.2s ease;
            user-select: none;
            white-space: nowrap;
        }

        .sbs-followup-btn:hover {
            background: rgba(102, 126, 234, 0.32);
            border-color: rgba(102, 126, 234, 0.7);
            transform: translateY(-1px);
        }

        .sbs-followup-btn:active {
            transform: translateY(0);
        }

        .sbs-followup-btn:disabled {
            opacity: 0.4;
            cursor: not-allowed;
            transform: none;
        }

        .sbs-state-hint {
            font-size: 0.72rem;
            color: rgba(255, 255, 255, 0.55);
            margin-top: 0.45rem;
            font-style: italic;
        }

        .toggle-switch {
            position: relative;
            width: 40px;
            height: 20px;
            background: rgba(255, 255, 255, 0.2);
            border-radius: 20px;
            transition: background 0.3s ease;
            cursor: pointer;
        }

        .toggle-switch.active {
            background: rgba(102, 126, 234, 0.8);
        }

        .toggle-switch::after {
            content: '';
            position: absolute;
            width: 16px;
            height: 16px;
            border-radius: 50%;
            background: white;
            top: 2px;
            left: 2px;
            transition: left 0.3s ease;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
        }

        .toggle-switch.active::after {
            left: 22px;
        }

        .toggle-label {
            user-select: none;
        }

        .export-btn:disabled {
            opacity: 0.5;
            cursor: not-allowed;
        }

        .chat-messages {
            flex: 1;
            padding: 1.5rem;
            overflow-y: auto;
            overflow-x: hidden;
            display: flex;
            flex-direction: column;
            gap: 1rem;
            min-height: 0;
            scroll-behavior: smooth;
        }
        
        .chat-messages::-webkit-scrollbar {
            width: 8px;
        }
        
        .chat-messages::-webkit-scrollbar-track {
            background: rgba(255, 255, 255, 0.1);
            border-radius: 10px;
        }
        
        .chat-messages::-webkit-scrollbar-thumb {
            background: rgba(255, 255, 255, 0.3);
            border-radius: 10px;
        }
        
        .chat-messages::-webkit-scrollbar-thumb:hover {
            background: rgba(255, 255, 255, 0.5);
        }

        .message {
            max-width: 70%;
            padding: 1rem 1.5rem;
            border-radius: 20px;
            font-size: 0.95rem;
            line-height: 1.6;
            word-wrap: break-word;
            overflow-wrap: break-word;
        }

        /* Markdown Styling inside messages */
        .message h1, .message h2, .message h3, .message h4, .message h5, .message h6 {
            margin: 0.75rem 0 0.5rem 0;
            font-weight: 700;
            line-height: 1.3;
        }

        .message h1 { font-size: 1.5rem; }
        .message h2 { font-size: 1.3rem; }
        .message h3 { font-size: 1.15rem; }
        .message h4 { font-size: 1rem; }

        .message p {
            margin: 0.5rem 0;
        }

        .message strong {
            font-weight: 700;
            color: inherit;
        }

        .message em {
            font-style: italic;
        }

        .message code {
            background: rgba(0, 0, 0, 0.2);
            padding: 0.2rem 0.4rem;
            border-radius: 4px;
            font-family: 'Courier New', monospace;
            font-size: 0.9em;
        }

        .message pre {
            background: rgba(0, 0, 0, 0.4);
            padding: 1rem;
            border-radius: 8px;
            overflow-x: auto;
            margin: 0.75rem 0;
            position: relative;
        }

        .message pre code {
            background: none;
            padding: 0;
            font-family: 'Fira Code', 'Monaco', 'Consolas', monospace;
            font-size: 0.9rem;
            line-height: 1.5;
        }

        .message pre code.hljs {
            background: transparent;
            padding: 0;
        }

        /* Code block copy button */
        .code-block-wrapper {
            position: relative;
        }

        .copy-code-btn {
            position: absolute;
            top: 8px;
            right: 8px;
            padding: 4px 8px;
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 4px;
            color: rgba(255, 255, 255, 0.7);
            font-size: 0.75rem;
            cursor: pointer;
            transition: all 0.2s ease;
            opacity: 0;
        }

        .code-block-wrapper:hover .copy-code-btn {
            opacity: 1;
        }

        .copy-code-btn:hover {
            background: rgba(255, 255, 255, 0.2);
            color: white;
        }

        .copy-code-btn.copied {
            background: rgba(78, 205, 196, 0.3);
            border-color: rgba(78, 205, 196, 0.5);
        }

        .message ul, .message ol {
            margin: 0.5rem 0;
            padding-left: 1.5rem;
        }

        .message li {
            margin: 0.25rem 0;
        }

        .message blockquote {
            border-left: 3px solid rgba(255, 255, 255, 0.3);
            padding-left: 1rem;
            margin: 0.75rem 0;
            opacity: 0.9;
        }

        .message a {
            color: inherit;
            text-decoration: underline;
            opacity: 0.9;
        }

        .message a:hover {
            opacity: 1;
        }

        .message hr {
            border: none;
            border-top: 1px solid rgba(255, 255, 255, 0.2);
            margin: 1rem 0;
        }

        .message table {
            border-collapse: collapse;
            width: 100%;
            margin: 0.75rem 0;
        }

        .message th, .message td {
            border: 1px solid rgba(255, 255, 255, 0.2);
            padding: 0.5rem;
            text-align: left;
        }

        .message th {
            background: rgba(255, 255, 255, 0.1);
            font-weight: 600;
        }

        /* KaTeX Math Styling */
        .message .katex {
            font-size: 1.1em;
            color: inherit;
        }

        .message .katex-display {
            margin: 1rem 0;
            padding: 0.75rem;
            background: rgba(0, 0, 0, 0.15);
            border-radius: 8px;
            overflow-x: auto;
        }

        .message .katex-display > .katex {
            text-align: left;
        }

        /* Welcome message for empty chat */
        .welcome-message {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            height: 100%;
            text-align: center;
            color: rgba(255, 255, 255, 0.9);
        }

        .welcome-message h2 {
            font-size: 2rem;
            font-weight: 600;
            margin-bottom: 0.5rem;
            text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
        }

        .welcome-message p {
            font-size: 1rem;
            color: rgba(255, 255, 255, 0.6);
            margin: 0;
        }

        .message.new {
            animation: messageSlide 0.3s ease-out;
        }

        /* Typing Indicator */
        .typing-indicator {
            max-width: 70%;
            padding: 1rem 1.5rem;
            border-radius: 20px;
            font-size: 0.95rem;
            line-height: 1.5;
            background: rgba(255, 255, 255, 0.15);
            color: #ffffff;
            align-self: flex-start;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            animation: messageSlide 0.3s ease-out;
        }

        .typing-dots {
            display: flex;
            gap: 0.3rem;
            align-items: center;
        }

        .typing-dot {
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.7);
            animation: typingBounce 1.4s infinite ease-in-out;
        }

        .typing-dot:nth-child(1) {
            animation-delay: 0s;
        }

        .typing-dot:nth-child(2) {
            animation-delay: 0.2s;
        }

        .typing-dot:nth-child(3) {
            animation-delay: 0.4s;
        }

        @keyframes typingBounce {
            0%, 60%, 100% {
                transform: translateY(0);
                opacity: 0.7;
            }
            30% {
                transform: translateY(-10px);
                opacity: 1;
            }
        }

        @keyframes messageSlide {
            from {
                opacity: 0;
                transform: translateY(10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .message.ai {
            background: rgba(255, 255, 255, 0.15);
            color: #ffffff;
            align-self: flex-start;
            border: 1px solid rgba(255, 255, 255, 0.2);
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
        }

        .message.student {
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: #ffffff;
            align-self: flex-end;
            box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
        }

        /* Message attachments display */
        .message-attachments {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
            margin-bottom: 8px;
        }

        .message-attachment-img {
            max-width: 200px;
            max-height: 150px;
            border-radius: 8px;
            object-fit: cover;
            cursor: pointer;
            transition: transform 0.2s ease;
        }

        .message-attachment-img:hover {
            transform: scale(1.05);
        }

        .message-attachment-file {
            display: flex;
            align-items: center;
            gap: 6px;
            padding: 6px 10px;
            background: rgba(255, 255, 255, 0.15);
            border-radius: 6px;
            font-size: 0.85rem;
        }

        .message.student .message-attachment-file {
            background: rgba(255, 255, 255, 0.2);
        }

        .message.ai .message-attachment-file {
            background: rgba(0, 0, 0, 0.1);
        }

        .message-text {
            margin-top: 4px;
        }

        .message-text:empty {
            display: none;
        }

        .chat-input-area {
            padding: 1.5rem;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            transition: all 0.2s ease;
            border-radius: 0 0 20px 20px;
        }
        
        .chat-input-area.drag-over {
            background: rgba(255, 255, 255, 0.15);
            border-color: rgba(78, 205, 196, 0.5);
        }

        .chat-input-container {
            display: flex;
            gap: 1rem;
            align-items: center;
        }

        .chat-input {
            flex: 1;
            padding: 1rem 1.5rem;
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 25px;
            background: rgba(255, 255, 255, 0.1);
            color: #ffffff;
            font-size: 0.95rem;
            backdrop-filter: blur(10px);
            transition: all 0.3s ease;
            resize: none;
            min-height: 50px;
            max-height: 150px;
            overflow-y: hidden; /* Start hidden, will be enabled when needed */
            font-family: inherit;
            line-height: 1.5;
        }
        
        .chat-input.scrollable {
            overflow-y: auto; /* Enable scrollbar only when content exceeds 3-4 lines */
        }

        .chat-input::placeholder {
            color: rgba(255, 255, 255, 0.6);
        }

        .chat-input:focus {
            outline: none;
            border-color: rgba(255, 255, 255, 0.4);
            box-shadow: 0 0 20px rgba(255, 255, 255, 0.1);
        }

        .send-btn {
            width: 50px;
            height: 50px;
            border-radius: 50%;
            background: linear-gradient(135deg, #ff6b6b, #4ecdc4);
            border: none;
            color: white;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
        }

        .send-btn:hover {
            transform: scale(1.1);
            box-shadow: 0 6px 25px rgba(0, 0, 0, 0.3);
        }

        .send-btn::before {
            content: "➤";
            font-size: 1.2rem;
        }

        .send-btn.is-generating::before {
            content: "■";
            font-size: 0.95rem;
        }

        /* Attachment Button */
        .attach-btn {
            width: 45px;
            height: 45px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
            color: white;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s ease;
            font-size: 1.3rem;
        }

        .attach-btn:hover {
            background: rgba(255, 255, 255, 0.2);
            border-color: rgba(255, 255, 255, 0.4);
            transform: scale(1.05);
        }

        /* File Preview Area */
        .file-preview-area {
            display: none;
            flex-wrap: wrap;
            gap: 0.75rem;
            padding: 1rem;
            background: rgba(255, 255, 255, 0.05);
            border-radius: 12px;
            margin-bottom: 1rem;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .file-preview-area.has-files {
            display: flex;
        }

        .file-chip {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            padding: 0.5rem 0.75rem;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 20px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            color: white;
            font-size: 0.85rem;
            max-width: 200px;
        }

        .file-chip-image {
            flex-direction: column;
            padding: 0.4rem;
            max-width: 90px;
            position: relative;
        }

        .file-chip-image .file-thumb {
            width: 80px;
            height: 60px;
            object-fit: cover;
            border-radius: 6px;
        }

        .file-chip-image .file-remove {
            position: absolute;
            top: -6px;
            right: -6px;
            width: 18px;
            height: 18px;
            font-size: 0.75rem;
        }

        .file-chip .file-icon {
            font-size: 1.2rem;
        }

        .file-chip .file-info {
            flex: 1;
            overflow: hidden;
        }

        .file-chip .file-name {
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
            font-weight: 500;
        }

        .file-chip .file-size {
            font-size: 0.75rem;
            opacity: 0.7;
        }

        .file-chip .file-remove {
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background: rgba(255, 107, 107, 0.8);
            border: none;
            color: white;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 0.9rem;
            transition: all 0.2s ease;
        }

        .file-chip .file-remove:hover {
            background: rgba(255, 107, 107, 1);
            transform: scale(1.1);
        }

        /* Upload Progress */
        .upload-progress {
            display: none;
            padding: 0.75rem;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 8px;
            margin-bottom: 1rem;
            color: white;
        }

        .upload-progress.active {
            display: block;
        }

        .upload-progress-bar {
            height: 4px;
            background: rgba(255, 255, 255, 0.2);
            border-radius: 2px;
            overflow: hidden;
            margin-top: 0.5rem;
        }

        .upload-progress-fill {
            height: 100%;
            background: linear-gradient(90deg, #4ecdc4, #ff6b6b);
            border-radius: 2px;
            transition: width 0.3s ease;
            width: 0%;
        }

        /* Hidden file input */
        .file-input-hidden {
            display: none;
        }

        /* Text Selection Tooltip - Ask StudyMate */
        .selection-tooltip {
            position: absolute;
            display: none;
            z-index: 1000;
            animation: tooltipFadeIn 0.15s ease-out;
        }

        .selection-tooltip.show {
            display: flex;
        }

        @keyframes tooltipFadeIn {
            from {
                opacity: 0;
                transform: translateY(4px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .selection-tooltip-btn {
            display: flex;
            align-items: center;
            gap: 6px;
            padding: 8px 14px;
            background: #2d2d2d;
            border: 1px solid rgba(255, 255, 255, 0.15);
            border-radius: 8px;
            color: #ffffff;
            font-size: 0.85rem;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s ease;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
            white-space: nowrap;
        }

        .selection-tooltip-btn:hover {
            background: #3d3d3d;
            border-color: rgba(255, 255, 255, 0.25);
            transform: translateY(-1px);
            box-shadow: 0 6px 24px rgba(0, 0, 0, 0.5);
        }

        .selection-tooltip-btn::before {
            content: "99";
            font-family: Georgia, serif;
            font-size: 1rem;
            font-weight: bold;
            color: rgba(255, 255, 255, 0.8);
        }

        /* Reply Quote Box - Above Chat Input */
        .reply-quote-box {
            display: none;
            padding: 12px 16px;
            margin-bottom: 12px;
            background: rgba(45, 45, 45, 0.95);
            border-radius: 12px;
            border-left: 3px solid #4ecdc4;
            position: relative;
            animation: replyBoxSlideIn 0.2s ease-out;
        }

        .reply-quote-box.show {
            display: block;
        }

        @keyframes replyBoxSlideIn {
            from {
                opacity: 0;
                transform: translateY(10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .reply-quote-header {
            display: flex;
            align-items: center;
            gap: 6px;
            margin-bottom: 8px;
            color: rgba(255, 255, 255, 0.6);
            font-size: 0.75rem;
        }

        .reply-quote-header svg {
            width: 14px;
            height: 14px;
            opacity: 0.7;
        }

        .reply-quote-content {
            color: rgba(255, 255, 255, 0.9);
            font-size: 0.9rem;
            line-height: 1.5;
            max-height: 80px;
            overflow-y: auto;
            padding-right: 8px;
            /* Show ellipsis for long text */
            display: -webkit-box;
            -webkit-line-clamp: 3;
            line-clamp: 3;
            -webkit-box-orient: vertical;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .reply-quote-content::-webkit-scrollbar {
            width: 4px;
        }

        .reply-quote-content::-webkit-scrollbar-thumb {
            background: rgba(255, 255, 255, 0.2);
            border-radius: 2px;
        }

        .reply-quote-close {
            position: absolute;
            top: 8px;
            right: 8px;
            width: 22px;
            height: 22px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.1);
            border: none;
            color: rgba(255, 255, 255, 0.6);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 14px;
            transition: all 0.2s ease;
        }

        .reply-quote-close:hover {
            background: rgba(255, 107, 107, 0.3);
            color: #ff6b6b;
        }

        /* Message Quote - Shows selected context in user messages */
        .message-quote {
            display: flex;
            align-items: flex-start;
            gap: 8px;
            padding: 10px 12px;
            margin-bottom: 10px;
            background: rgba(0, 0, 0, 0.2);
            border-radius: 10px;
            border-left: 3px solid rgba(255, 255, 255, 0.4);
        }

        .message-quote-icon {
            flex-shrink: 0;
            width: 18px;
            height: 18px;
            opacity: 0.7;
            margin-top: 2px;
        }

        .message-quote-text {
            flex: 1;
            font-size: 0.88rem;
            line-height: 1.5;
            color: rgba(255, 255, 255, 0.85);
            display: -webkit-box;
            -webkit-line-clamp: 4;
            line-clamp: 4;
            -webkit-box-orient: vertical;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        /* Progress Sidebar */
        .progress-sidebar {
            flex: 0 0 280px;
            display: flex;
            flex-direction: column;
            gap: 0.5rem;
            max-width: 280px;
            align-self: stretch;
        }

        .progress-card {
            flex: 1;
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            border-radius: 14px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            padding: 0.75rem;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            transition: all 0.3s ease;
            display: flex;
            flex-direction: column;
        }

        .progress-card:hover {
            transform: translateY(-2px);
            box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
        }

        .card-title {
            color: #ffffff;
            font-weight: 600;
            margin-bottom: 0.5rem;
            font-size: 0.85rem;
        }

        .progress-bar-container {
            background: rgba(255, 255, 255, 0.1);
            border-radius: 10px;
            height: 8px;
            overflow: hidden;
            margin-bottom: 0.5rem;
        }

        .progress-bar {
            height: 100%;
            background: linear-gradient(90deg, #ff6b6b, #4ecdc4);
            border-radius: 10px;
            transition: width 0.8s ease;
            box-shadow: 0 0 10px rgba(255, 107, 107, 0.5);
        }

        .progress-text {
            color: rgba(255, 255, 255, 0.8);
            font-size: 0.9rem;
            text-align: right;
        }

        .stat-number {
            font-size: 1.4rem;
            font-weight: 700;
            color: #ffffff;
            text-shadow: 0 0 20px rgba(255, 255, 255, 0.5);
            text-align: center;
            margin: auto 0;
        }

        .stat-label {
            color: rgba(255, 255, 255, 0.7);
            font-size: 0.7rem;
            margin-top: 0.2rem;
            text-align: center;
        }

        .task-item {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            padding: 0.75rem 0;
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        }

        .task-item:last-child {
            border-bottom: none;
        }

        .task-icon {
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background: linear-gradient(135deg, #ff6b6b, #4ecdc4);
            box-shadow: 0 0 10px rgba(255, 107, 107, 0.5);
        }

        .task-text {
            color: rgba(255, 255, 255, 0.9);
            font-size: 0.9rem;
            flex: 1;
        }

        /* Stat Subtext */
        .stat-subtext {
            color: rgba(255, 255, 255, 0.6);
            font-size: 0.7rem;
            margin-top: 0.2rem;
            text-align: center;
        }

        /* Quote Container */
        .quote-container {
            color: rgba(255, 255, 255, 0.9);
            font-size: 0.75rem;
            line-height: 1.4;
            font-style: italic;
            padding: 0.5rem;
            background: rgba(255, 255, 255, 0.05);
            border-radius: 8px;
            margin-bottom: 0.5rem;
            flex: 1;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
        }

        .refresh-quote-btn {
            width: 100%;
            padding: 0.5rem;
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            border: none;
            border-radius: 8px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 0.75rem;
        }

        .refresh-quote-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px #667eea66;
        }

        /* Sidebar AI preference sliders */
        .progress-sidebar .pref-card {
            flex: 0 0 auto;
        }

        .pref-slider-row {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            margin-top: 0.25rem;
        }

        .pref-slider {
            flex: 1;
            -webkit-appearance: none;
            appearance: none;
            height: 6px;
            background: var(--sm-surface-inset, #d0ced8);
            border-radius: 4px;
            outline: none;
            cursor: pointer;
        }

        .pref-slider::-webkit-slider-thumb {
            -webkit-appearance: none;
            appearance: none;
            width: 16px;
            height: 16px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            border-radius: 50%;
            cursor: pointer;
            box-shadow: 0 2px 8px rgba(102, 126, 234, 0.4);
        }

        .pref-slider::-moz-range-thumb {
            width: 16px;
            height: 16px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            border-radius: 50%;
            cursor: pointer;
            border: none;
        }

        .pref-slider-value {
            min-width: 2rem;
            padding: 0.25rem 0.4rem;
            background: var(--sm-ai-highlight, #e8e4f0);
            border: 1px solid var(--sm-ai-border, #c4c2ce);
            border-radius: 6px;
            color: var(--sm-brand-700, #5a6a9e);
            font-weight: 600;
            text-align: center;
            font-size: 0.75rem;
        }

        .pref-detail-value {
            min-width: 4.5rem;
            font-size: 0.65rem;
            line-height: 1.2;
        }

        .pref-slider-labels {
            display: flex;
            justify-content: space-between;
            margin-top: 0.35rem;
            color: var(--sm-ink-muted, #5f6578);
            font-size: 0.65rem;
        }

        /* Timer Display */
        .timer-display {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--sm-ink, #1a1f2e);
            text-align: center;
            margin: 0.5rem 0;
            font-variant-numeric: tabular-nums;
            text-shadow: none;
        }

        .timer-controls {
            display: flex;
            gap: 0.5rem;
            margin-bottom: 0.5rem;
        }

        .timer-btn {
            flex: 1;
            padding: 0.5rem;
            border: none;
            border-radius: 8px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 0.75rem;
        }

        .timer-btn-start {
            background: linear-gradient(135deg, #4ecdc4, #44a08d);
            color: white;
        }

        .timer-btn-start:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(78, 205, 196, 0.4);
        }

        .timer-btn-pause {
            background: linear-gradient(135deg, #ffd93d, #f4a261);
            color: white;
        }

        .timer-btn-pause:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(255, 217, 61, 0.4);
        }

        .timer-btn-reset {
            background: var(--sm-surface-soft, #dbd8e6);
            color: var(--sm-ink, #1a1f2e);
            border: 1px solid var(--sm-border, #c4c2ce);
        }

        .timer-btn-reset:hover:not(:disabled) {
            background: var(--sm-ai-highlight, #e8e4f0);
            border-color: var(--sm-ai-border, #b8b4c8);
            color: var(--sm-brand-700, #5a6a9e);
        }

        .timer-btn-reset:disabled {
            background: var(--sm-surface-muted, #dad8e1);
            color: var(--sm-ink-muted, #5f6578);
            border-color: var(--sm-border, #c4c2ce);
            opacity: 0.9;
            cursor: not-allowed;
        }

        .timer-btn-reset:focus-visible {
            outline: 2px solid var(--sm-border-focus, #bba2ff);
            outline-offset: 2px;
        }

        .timer-presets {
            display: flex;
            gap: 0.4rem;
            margin-bottom: 0.4rem;
        }

        .preset-btn {
            flex: 1;
            padding: 0.4rem;
            background: var(--sm-surface-muted, #dad8e1);
            color: var(--sm-ink-secondary, #3a4155);
            border: 1px solid var(--sm-border, #c4c2ce);
            border-radius: 6px;
            font-size: 0.7rem;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .preset-btn:hover {
            background: var(--sm-surface-inset, #d0ced8);
            border-color: var(--sm-border-strong, #b2b0bc);
            color: var(--sm-ink, #1a1f2e);
        }

        .preset-btn.active {
            background: var(--sm-ai-highlight, #e8e4f0);
            border-color: var(--sm-ai-border, #b8b4c8);
            color: var(--sm-brand-700, #5a6a9e);
        }

        .timer-custom {
            display: flex;
            gap: 0.4rem;
            padding-top: 0.4rem;
            border-top: 1px solid var(--sm-border, #c4c2ce);
        }

        .custom-time-input {
            flex: 1;
            padding: 0.4rem;
            background: var(--sm-surface-soft, #dbd8e6);
            color: var(--sm-ink, #1a1f2e);
            border: 1px solid var(--sm-border, #c4c2ce);
            border-radius: 6px;
            font-size: 0.75rem;
            outline: none;
            transition: all 0.3s ease;
        }

        .custom-time-input::placeholder {
            color: var(--sm-ink-placeholder, #8b91a3);
        }

        .custom-time-input:focus {
            background: var(--sm-surface-raised, #e8e6ed);
            border-color: var(--sm-border-focus, #bba2ff);
            box-shadow: var(--shadow-focus, 0 0 0 3px color-mix(in srgb, var(--sm-lavender) 25%, transparent));
        }

        .custom-time-input:disabled {
            background: var(--sm-surface-muted, #dad8e1);
            color: var(--sm-ink-muted, #5f6578);
            cursor: not-allowed;
        }

        .custom-time-btn {
            padding: 0.4rem 0.8rem;
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            border: none;
            border-radius: 6px;
            font-weight: 600;
            font-size: 0.75rem;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .custom-time-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .main-content {
                flex-direction: column;
                padding: 1rem;
                gap: 1rem;
            }

            .progress-sidebar {
                flex-direction: row;
                overflow-x: auto;
            }

            .progress-card {
                min-width: 200px;
            }

            .top-nav {
                padding: 1rem;
            }

            .chat-selector {
                flex: 0 0 220px;
            }

            .top-nav .toggle-sidebar-btn {
                width: 34px;
                height: 34px;
                font-size: 1rem;
            }
        }

        /* Modal Styles */
        .modal-overlay {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.7);
            backdrop-filter: blur(5px);
            display: none;
            justify-content: center;
            align-items: center;
            z-index: 10000;
            animation: fadeIn 0.3s ease;
        }

        .modal-overlay.show {
            display: flex;
        }

        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }

        @keyframes slideUp {
            from { 
                transform: translateY(30px);
                opacity: 0;
            }
            to { 
                transform: translateY(0);
                opacity: 1;
            }
        }

        .modal-content {
            background: linear-gradient(135deg, rgba(255, 255, 255, 0.95), rgba(255, 255, 255, 0.9));
            backdrop-filter: blur(20px);
            border-radius: 20px;
            padding: 2rem;
            max-width: 450px;
            width: 90%;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
            animation: slideUp 0.3s ease;
            border: 1px solid rgba(255, 255, 255, 0.3);
        }

        .modal-header {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            margin-bottom: 1rem;
        }

        .modal-icon {
            width: 48px;
            height: 48px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            flex-shrink: 0;
        }

        .modal-icon.success {
            background: linear-gradient(135deg, #4ecdc4, #44a08d);
            box-shadow: 0 4px 15px rgba(78, 205, 196, 0.3);
        }

        .modal-icon.error {
            background: linear-gradient(135deg, #ff6b6b, #ee5a52);
            box-shadow: 0 4px 15px rgba(255, 107, 107, 0.3);
        }

        .modal-icon.warning {
            background: linear-gradient(135deg, #ffd93d, #f4a261);
            box-shadow: 0 4px 15px rgba(255, 217, 61, 0.3);
        }

        .modal-icon.info {
            background: linear-gradient(135deg, #667eea, #764ba2);
            box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
        }

        .modal-title {
            font-size: 1.5rem;
            font-weight: 700;
            color: #2d3748;
            margin: 0;
        }

        .modal-body {
            color: #4a5568;
            font-size: 1rem;
            line-height: 1.6;
            margin-bottom: 1.5rem;
        }

        .modal-buttons {
            display: flex;
            gap: 1rem;
            justify-content: flex-end;
        }

        .modal-btn {
            padding: 0.75rem 1.5rem;
            border-radius: 12px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            border: none;
            font-size: 1rem;
        }

        .modal-btn-primary {
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
        }

        .modal-btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
        }

        .modal-btn-danger {
            background: linear-gradient(135deg, #ff6b6b, #ee5a52);
            color: white;
            box-shadow: 0 4px 15px rgba(255, 107, 107, 0.3);
        }

        .modal-btn-danger:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(255, 107, 107, 0.4);
        }

        .modal-btn-secondary {
            background: rgba(0, 0, 0, 0.05);
            color: #4a5568;
        }

        .modal-btn-secondary:hover {
            background: rgba(0, 0, 0, 0.1);
        }

/* Legacy theme overrides (prefer studymate-shell.css) */

html {
  height: 100%;
  overflow: hidden;
}

body {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: var(--sm-font);
  font-size: var(--sm-text-base);
  line-height: var(--sm-leading-normal);
  color: var(--sm-ink);
  background: var(--sm-bg);
  background-image:
    radial-gradient(ellipse 70% 50% at 0% 0%, rgba(248, 168, 232, 0.08), transparent 55%),
    radial-gradient(ellipse 60% 45% at 100% 100%, rgba(152, 184, 248, 0.1), transparent 50%);
  height: 100vh;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

body *,
body *::before,
body *::after {
  box-sizing: border-box;
}

.app-container {
  backdrop-filter: none;
}

.top-nav {
  background: var(--sm-surface);
  backdrop-filter: none;
  border-bottom: 1px solid var(--sm-border);
  padding: var(--space-3) var(--space-6);
  box-shadow: var(--shadow-xs);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--sm-text-lg);
  font-weight: var(--sm-weight-bold);
  color: var(--sm-ink);
  text-shadow: none;
  letter-spacing: -0.02em;
}

.logo::before {
  content: '';
  width: 32px;
  height: 32px;
  flex-shrink: 0;
  background: url('../assets/logo.png') center / contain no-repeat;
}

.profile-btn {
  background: var(--sm-gradient-subtle);
  border: 1px solid var(--sm-border);
  box-shadow: var(--shadow-xs);
}

.profile-btn:hover {
  border-color: var(--sm-ai-border);
  box-shadow: var(--shadow-sm);
}

.logout-btn {
  background: var(--sm-surface-muted);
  border: 1px solid var(--sm-border);
  color: var(--sm-ink-secondary);
  box-shadow: none;
}

.logout-btn:hover {
  background: var(--sm-danger-bg);
  border-color: rgba(220, 76, 76, 0.35);
  color: var(--sm-danger);
  transform: none;
  box-shadow: none;
}

.top-nav .toggle-sidebar-btn {
  background: var(--sm-surface-muted);
  border: 1px solid var(--sm-border);
  color: var(--sm-ink-secondary);
}

.top-nav .toggle-sidebar-btn:hover {
  background: var(--sm-surface-inset);
  color: var(--sm-ink);
}

.chat-selector,
.chat-container,
.progress-card {
  background: var(--sm-surface);
  backdrop-filter: none;
  border: 1px solid var(--sm-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.chat-selector-header,
.chat-header {
  color: var(--sm-ink);
  border-bottom-color: var(--sm-border);
}

.chat-search-input {
  background: var(--sm-surface-muted);
  border-color: var(--sm-border);
  color: var(--sm-ink);
  border-radius: var(--radius-full);
}

.chat-search-input::placeholder {
  color: var(--sm-ink-placeholder);
}

.chat-search-input:focus {
  border-color: var(--sm-border-focus);
  background: var(--sm-surface);
  box-shadow: var(--shadow-focus);
}

.chat-item {
  background: var(--sm-surface-muted);
  border-color: var(--sm-border);
  color: var(--sm-ink);
}

.chat-item:hover {
  background: var(--sm-surface-inset);
  border-color: var(--sm-border-strong);
  transform: translateX(4px);
}

.chat-item.active {
  background: var(--sm-ai-highlight);
  border-color: var(--sm-ai-border);
  box-shadow: var(--shadow-xs);
}

.new-chat-btn,
.send-btn {
  background: var(--sm-gradient-cta);
  box-shadow: var(--shadow-brand);
}

.new-chat-btn:hover,
.send-btn:hover {
  background: var(--sm-gradient-cta-hover);
  transform: scale(1.05);
}

.message.ai {
  background: var(--sm-surface-muted);
  color: var(--sm-ink);
  border-color: var(--sm-border);
}

.message.student {
  background: var(--sm-gradient-cta);
  color: var(--sm-ink-inverse);
  box-shadow: var(--shadow-brand);
}

.welcome-message {
  color: var(--sm-ink-secondary);
}

.welcome-message h2 {
  color: var(--sm-ink);
  text-shadow: none;
}

.welcome-message p {
  color: var(--sm-ink-muted);
}

.chat-input {
  background: var(--sm-surface-muted);
  border-color: var(--sm-border);
  color: var(--sm-ink);
}

.chat-input::placeholder {
  color: var(--sm-ink-placeholder);
}

.chat-input:focus {
  border-color: var(--sm-border-focus);
  box-shadow: var(--shadow-focus);
}

.typing-indicator {
  background: var(--sm-surface-muted);
  color: var(--sm-ink-muted);
}

.typing-dot {
  background: var(--sm-lavender);
}

.card-title,
.timer-display,
.stat-number {
  color: var(--sm-ink);
  text-shadow: none;
}

.progress-text,
.stat-label,
.pref-slider-labels,
.task-text {
  color: var(--sm-ink-muted);
}

.export-btn,
.advanced-reasoning-toggle,
.step-by-step-toggle,
.attach-btn,
.preset-btn {
  background: var(--sm-surface-muted);
  border-color: var(--sm-border);
  color: var(--sm-ink-secondary);
}

.export-btn:hover,
.advanced-reasoning-toggle:hover,
.step-by-step-toggle:hover {
  background: var(--sm-surface-inset);
  color: var(--sm-ink);
}

.advanced-reasoning-toggle.active {
  background: var(--sm-ai-highlight);
  border-color: var(--sm-ai-border);
  color: var(--sm-ink);
}

.step-by-step-toggle.active {
  background: var(--sm-success-bg);
  border-color: rgba(13, 159, 110, 0.35);
  color: var(--sm-success);
}

.toggle-switch.active {
  background: var(--sm-lavender);
}

.entitlements-chip {
  background: var(--sm-surface-muted);
  border-color: var(--sm-border);
  color: var(--sm-ink-secondary);
}

.classes-panel {
  background: var(--sm-surface-inset);
  border-bottom-color: var(--sm-border);
}

.classes-panel-title,
.sidebar-section-label {
  color: var(--sm-ink-muted);
}

.class-project-header {
  color: var(--sm-ink);
}

.class-project-header:hover {
  background: var(--sm-surface-muted);
}

.class-project-header.active {
  background: var(--sm-ai-highlight);
}

.academic-profile-banner {
  background: var(--sm-ai-highlight);
  border-color: var(--sm-ai-border);
  color: var(--sm-ink-secondary);
}

.academic-profile-banner strong {
  color: var(--sm-ink);
}

.class-context-badge {
  background: var(--sm-ai-highlight);
  color: var(--sm-brand-700);
}

.sm-quota-card {
  background: var(--sm-surface);
  border-color: var(--sm-border);
  color: var(--sm-ink);
  box-shadow: var(--shadow-lg);
}

.sm-quota-card p {
  color: var(--sm-ink-muted);
}

.sm-quota-btn {
  background: var(--sm-surface-muted);
  border-color: var(--sm-border);
  color: var(--sm-ink);
}

.sm-quota-btn.primary {
  background: var(--sm-gradient-cta);
  color: var(--sm-ink-inverse);
}

.progress-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.pref-slider::-webkit-slider-thumb,
.pref-slider::-moz-range-thumb,
.refresh-quote-btn,
.custom-time-btn,
.modal-btn-primary {
  background: var(--sm-gradient-cta);
}

.progress-bar,
.upload-progress-fill {
  background: var(--sm-gradient-cta);
}

.timer-btn-start {
  background: var(--sm-success);
}

.timer-btn-pause {
  background: var(--sm-warning);
}

.progress-sidebar .pref-slider {
  background: var(--sm-surface-inset);
}

.progress-sidebar .pref-slider-value,
.progress-sidebar .pref-detail-value {
  background: var(--sm-ai-highlight);
  border: 1px solid var(--sm-ai-border);
  color: var(--sm-brand-700);
}

.progress-sidebar .timer-btn-reset {
  background: var(--sm-surface-soft);
  color: var(--sm-ink);
  border: 1px solid var(--sm-border);
}

.progress-sidebar .timer-btn-reset:hover:not(:disabled) {
  background: var(--sm-ai-highlight);
  border-color: var(--sm-ai-border);
  color: var(--sm-brand-700);
}

.progress-sidebar .timer-btn-reset:disabled {
  background: var(--sm-surface-muted);
  color: var(--sm-ink-muted);
  border-color: var(--sm-border);
  opacity: 0.9;
  cursor: not-allowed;
}

.progress-sidebar .custom-time-input {
  background: var(--sm-surface-soft);
  color: var(--sm-ink);
  border: 1px solid var(--sm-border);
}

.progress-sidebar .custom-time-input::placeholder {
  color: var(--sm-ink-placeholder);
}

.progress-sidebar .custom-time-input:focus {
  background: var(--sm-surface-raised);
  border-color: var(--sm-border-focus);
  box-shadow: var(--shadow-focus);
}

.progress-sidebar .timer-custom {
  border-top-color: var(--sm-border);
}

.selection-tooltip-btn {
  background: var(--sm-ink);
  color: var(--sm-ink-inverse);
  border-color: transparent;
}

.reply-quote-box {
  background: var(--sm-surface-inset);
  border-left-color: var(--sm-lavender);
}

.reply-quote-header {
  color: var(--sm-ink-muted);
}

.reply-quote-content {
  color: var(--sm-ink-secondary);
}

.sbs-btn,
.sbs-followup-btn {
  background: var(--sm-surface-muted);
  border-color: var(--sm-border);
  color: var(--sm-ink);
}

.sbs-followup-btn {
  border-color: var(--sm-ai-border);
  background: var(--sm-ai-highlight);
}

.sbs-state-hint {
  color: var(--sm-ink-muted);
}

.main-content::-webkit-scrollbar-track,
.chat-messages::-webkit-scrollbar-track {
  background: var(--sm-surface-inset);
}

.main-content::-webkit-scrollbar-thumb,
.chat-messages::-webkit-scrollbar-thumb {
  background: var(--sm-border-strong);
}

@media (max-width: 1024px) {
  .progress-sidebar {
    display: none;
  }
}

@media (max-width: 768px) {
  .main-content {
    padding: var(--space-3);
  }

  .chat-selector {
    position: fixed;
    left: 0;
    top: var(--topnav-height);
    bottom: 0;
    z-index: var(--z-sticky);
    height: calc(100vh - var(--topnav-height));
    box-shadow: var(--shadow-lg);
  }

  .chat-selector.hidden {
    transform: translateX(-110%);
  }
}

@media (min-width: 769px) and (max-width: 1100px) {
  .chat-selector {
    flex: 0 0 240px;
  }
  .progress-sidebar {
    flex: 0 0 240px;
    max-width: 240px;
  }
}

.message.new {
  animation: messageSlide var(--duration-normal) var(--ease-out);
}

.chat-item {
  animation: chatItemIn var(--duration-normal) var(--ease-out) backwards;
}

.chat-list .chat-item:nth-child(1) { animation-delay: 0ms; }
.chat-list .chat-item:nth-child(2) { animation-delay: 40ms; }
.chat-list .chat-item:nth-child(3) { animation-delay: 80ms; }
.chat-list .chat-item:nth-child(4) { animation-delay: 120ms; }
.chat-list .chat-item:nth-child(5) { animation-delay: 160ms; }

@keyframes chatItemIn {
  from {
    opacity: 0;
    transform: translateX(-8px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.send-btn:active,
.new-chat-btn:active {
  transform: scale(0.96);
}

/* Focus visible for keyboard users */
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--sm-lavender);
  outline-offset: 2px;
}