/* Base Theme System - Windsurf/VSCode Font Stack */
:root {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #e1e5e9;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    
    /* GROUP 1: BACKGROUNDS & SURFACES */
    --bg-primary: #ffffff;      /* Main background */
    --bg-secondary: #f8fafc;    /* Cards, panels */
    --bg-tertiary: #f1f5f9;     /* Hover states, subtle backgrounds */
    
    /* GROUP 2: TEXT & CONTENT */
    --text-primary: #1e293b;    /* Main text, body content */
    --text-secondary: #64748b;  /* Secondary text, descriptions */
    --text-accent: #0f172a;     /* Headings, important text */
    
    /* GROUP 3: NAVIGATION & STRUCTURE */
    --nav-primary: #3b82f6;     /* Active tabs, primary navigation */
    --nav-secondary: #6b7280;   /* Inactive tabs, secondary nav */
    --section-header: #374151;  /* Section titles (Your Progress, Subjects) */
    
    /* GROUP 4: INTERACTIVE ELEMENTS */
    --interactive-primary: #3b82f6;   /* Primary buttons, main actions */
    --interactive-secondary: #8b5cf6; /* Secondary buttons, subject topics */
    --interactive-tertiary: #06b6d4;  /* Tertiary actions */
    
    /* GROUP 5: SEMANTIC COLORS */
    --success: #10b981;         /* Correct answers, success states */
    --error: #ef4444;           /* Incorrect answers, errors */
    --warning: #f59e0b;         /* Streaks, warnings */
    --info: #3b82f6;           /* Information, neutral states */
    
    /* GROUP 6: DATA & STATISTICS */
    --data-primary: #1e293b;    /* Numbers, statistics */
    --data-success: #10b981;    /* Correct count color */
    --data-error: #ef4444;      /* Incorrect count color */
    --data-warning: #f59e0b;    /* Streak count color */
}

/* 1. One Dark Pro - Official VSCode Theme */
[data-theme="one-dark-pro"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #3e4451;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    
    --bg-primary: #282c34;
    --bg-secondary: #21252b;
    --bg-tertiary: #2c313c;
    
    --text-primary: #abb2bf;
    --text-secondary: #5c6370;
    --text-accent: #e5c07b;
    
    --nav-primary: #61afef;
    --nav-secondary: #5c6370;
    --section-header: #c678dd;
    
    --interactive-primary: #61afef;
    --interactive-secondary: #d19a66;
    --interactive-tertiary: #56b6c2;
    
    --success: #98c379;
    --error: #e06c75;
    --warning: #e5c07b;
    --info: #61afef;
    
    --data-primary: #e5c07b;
    --data-success: #98c379;
    --data-error: #e06c75;
    --data-warning: #e5c07b;
}

/* 2. Dracula - Official Dracula Theme */
[data-theme="dracula"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #44475a;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
    
    --bg-primary: #282a36;
    --bg-secondary: #44475a;
    --bg-tertiary: #4e5273;
    
    --text-primary: #f8f8f2;
    --text-secondary: #b8c2e0;
    --text-accent: #ff79c6;
    
    --nav-primary: #bd93f9;
    --nav-secondary: #b8c2e0;
    --section-header: #8be9fd;
    
    --interactive-primary: #bd93f9;
    --interactive-secondary: #ffb86c;
    --interactive-tertiary: #8be9fd;
    
    --success: #50fa7b;
    --error: #ff5555;
    --warning: #f1fa8c;
    --info: #8be9fd;
    
    --data-primary: #ff79c6;
    --data-success: #50fa7b;
    --data-error: #ff5555;
    --data-warning: #f1fa8c;
}

/* 3. GitHub Dark - Official GitHub Theme */
[data-theme="github-dark"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #30363d;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --text-accent: #f0883e;
    
    --nav-primary: #58a6ff;
    --nav-secondary: #8b949e;
    --section-header: #a5a5ff;
    
    --interactive-primary: #58a6ff;
    --interactive-secondary: #ffa657;
    --interactive-tertiary: #79c0ff;
    
    --success: #56d364;
    --error: #f85149;
    --warning: #d29922;
    --info: #58a6ff;
    
    --data-primary: #79c0ff;
    --data-success: #56d364;
    --data-error: #f85149;
    --data-warning: #d29922;
}

/* 4. Monokai - Classic Sublime Text Theme */
[data-theme="monokai"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #49483e;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    
    --bg-primary: #272822;
    --bg-secondary: #3e3d32;
    --bg-tertiary: #49483e;
    
    --text-primary: #f8f8f2;
    --text-secondary: #75715e;
    --text-accent: #fd971f;
    
    --nav-primary: #66d9ef;
    --nav-secondary: #75715e;
    --section-header: #f92672;
    
    --interactive-primary: #66d9ef;
    --interactive-secondary: #ae81ff;
    --interactive-tertiary: #a6e22e;
    
    --success: #a6e22e;
    --error: #f92672;
    --warning: #e6db74;
    --info: #66d9ef;
    
    --data-primary: #fd971f;
    --data-success: #a6e22e;
    --data-error: #f92672;
    --data-warning: #e6db74;
}

/* 5. Solarized Dark - Eye-friendly Theme */
[data-theme="solarized-dark"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #073642;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    
    --bg-primary: #002b36;
    --bg-secondary: #073642;
    --bg-tertiary: #586e75;
    
    --text-primary: #839496;
    --text-secondary: #657b83;
    --text-accent: #cb4b16;
    
    --nav-primary: #268bd2;
    --nav-secondary: #657b83;
    --section-header: #d33682;
    
    --interactive-primary: #268bd2;
    --interactive-secondary: #6c71c4;
    --interactive-tertiary: #2aa198;
    
    --success: #859900;
    --error: #dc322f;
    --warning: #b58900;
    --info: #268bd2;
    
    --data-primary: #2aa198;
    --data-success: #859900;
    --data-error: #dc322f;
    --data-warning: #b58900;
}

/* 6. Material Theme - Google Material Design */
[data-theme="material-theme"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #37474f;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    
    --bg-primary: #263238;
    --bg-secondary: #37474f;
    --bg-tertiary: #546e7a;
    
    --text-primary: #eeffff;
    --text-secondary: #b0bec5;
    --text-accent: #ffcb6b;
    
    --nav-primary: #82aaff;
    --nav-secondary: #b0bec5;
    --section-header: #c792ea;
    
    --interactive-primary: #82aaff;
    --interactive-secondary: #f78c6c;
    --interactive-tertiary: #89ddff;
    
    --success: #c3e88d;
    --error: #f07178;
    --warning: #ffcb6b;
    --info: #89ddff;
    
    --data-primary: #89ddff;
    --data-success: #c3e88d;
    --data-error: #f07178;
    --data-warning: #ffcb6b;
}

/* 7. Nord - Arctic Blue Theme */
[data-theme="nord"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #3b4252;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    
    --bg-primary: #2e3440;
    --bg-secondary: #3b4252;
    --bg-tertiary: #434c5e;
    
    --text-primary: #d8dee9;
    --text-secondary: #81a1c1;
    --text-accent: #d08770;
    
    --nav-primary: #88c0d0;
    --nav-secondary: #81a1c1;
    --section-header: #5e81ac;
    
    --interactive-primary: #88c0d0;
    --interactive-secondary: #b48ead;
    --interactive-tertiary: #8fbcbb;
    
    --success: #a3be8c;
    --error: #bf616a;
    --warning: #ebcb8b;
    --info: #88c0d0;
    
    --data-primary: #8fbcbb;
    --data-success: #a3be8c;
    --data-error: #bf616a;
    --data-warning: #ebcb8b;
}

/* 8. Tokyo Night - Modern Dark Theme */
[data-theme="tokyo-night"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #24283b;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    
    --bg-primary: #1a1b26;
    --bg-secondary: #24283b;
    --bg-tertiary: #414868;
    
    --text-primary: #c0caf5;
    --text-secondary: #565f89;
    --text-accent: #ff9e64;
    
    --nav-primary: #7aa2f7;
    --nav-secondary: #565f89;
    --section-header: #bb9af7;
    
    --interactive-primary: #7aa2f7;
    --interactive-secondary: #f7768e;
    --interactive-tertiary: #7dcfff;
    
    --success: #9ece6a;
    --error: #f7768e;
    --warning: #e0af68;
    --info: #7aa2f7;
    
    --data-primary: #bb9af7;
    --data-success: #9ece6a;
    --data-error: #f7768e;
    --data-warning: #e0af68;
}

/* 9. Catppuccin Mocha - Pastel Dark Theme */
[data-theme="catppuccin"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #313244;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    
    --bg-primary: #1e1e2e;
    --bg-secondary: #313244;
    --bg-tertiary: #45475a;
    
    --text-primary: #cdd6f4;
    --text-secondary: #6c7086;
    --text-accent: #fab387;
    
    --nav-primary: #89b4fa;
    --nav-secondary: #6c7086;
    --section-header: #cba6f7;
    
    --interactive-primary: #89b4fa;
    --interactive-secondary: #f38ba8;
    --interactive-tertiary: #94e2d5;
    
    --success: #a6e3a1;
    --error: #f38ba8;
    --warning: #f9e2af;
    --info: #89b4fa;
    
    --data-primary: #cba6f7;
    --data-success: #a6e3a1;
    --data-error: #f38ba8;
    --data-warning: #f9e2af;
}

/* 10. Gruvbox Dark - Retro Warm Theme */
[data-theme="gruvbox"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #3c3836;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    
    --bg-primary: #282828;
    --bg-secondary: #3c3836;
    --bg-tertiary: #504945;
    
    --text-primary: #ebdbb2;
    --text-secondary: #a89984;
    --text-accent: #fe8019;
    
    --nav-primary: #83a598;
    --nav-secondary: #a89984;
    --section-header: #d3869b;
    
    --interactive-primary: #83a598;
    --interactive-secondary: #d79921;
    --interactive-tertiary: #8ec07c;
    
    --success: #b8bb26;
    --error: #fb4934;
    --warning: #fabd2f;
    --info: #83a598;
    
    --data-primary: #fe8019;
    --data-success: #b8bb26;
    --data-error: #fb4934;
    --data-warning: #fabd2f;
}

/* 11. Synthwave '84 - Retro Neon Theme */
[data-theme="synthwave"] {
    --font-family: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --code-font: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Source Code Pro', 'Menlo', 'Consolas', monospace;
    --border-color: #ff006e;
    --shadow: 0 4px 20px rgba(255, 0, 110, 0.3);
    
    --bg-primary: #2b213a;
    --bg-secondary: #241b2f;
    --bg-tertiary: #34294f;
    
    --text-primary: #ffffff;
    --text-secondary: #b084cc;
    --text-accent: #ff006e;
    
    --nav-primary: #ff006e;
    --nav-secondary: #b084cc;
    --section-header: #00d9ff;
    
    --interactive-primary: #ff006e;
    --interactive-secondary: #00d9ff;
    --interactive-tertiary: #f92aad;
    
    --success: #72f1b8;
    --error: #ff073a;
    --warning: #ffd319;
    --info: #00d9ff;
    
    --data-primary: #f92aad;
    --data-success: #72f1b8;
    --data-error: #ff073a;
    --data-warning: #ffd319;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    padding: 20px;
    transition: all 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    margin-bottom: 40px;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.header-text {
    text-align: center;
    flex: 1;
    font-family: var(--font-family);
}

h1 {
    color: var(--text-accent);
    margin-bottom: 10px;
    font-family: var(--font-family);
}

.category h3 {
    margin-bottom: 10px;
}

/* Mathematics header */
.category:first-child h3 {
    color: var(--section-header);
}

/* Physics header */
.category:last-child h3 {
    color: var(--section-header);
}

/* Buttons */
button, .btn, #hint-btn, #back-btn, #next-btn, .back-to-subjects, .subject-btn {
    padding: 10px 20px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-width: 100px;
    text-decoration: none;
}

/* Secondary buttons (back, hint, etc.) */
.secondary-btn {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 10px 20px;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
}

.secondary-btn:hover:not(:disabled) {
    background-color: var(--interactive-primary);
    color: var(--bg-primary);
    border-color: var(--interactive-primary);
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.secondary-btn:active:not(:disabled) {
    transform: translateY(0);
    box-shadow: none;
    background-color: var(--interactive-primary);
    color: var(--bg-primary);
}

.secondary-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
}

/* Primary button (submit, next) */
.primary-btn, #submit-answer {
    background-color: var(--interactive-primary);
    color: var(--bg-primary);
    border: 1px solid var(--interactive-primary);
}

.primary-btn:hover:not(:disabled),
#submit-answer:hover:not(:disabled) {
    background-color: var(--interactive-secondary);
    border-color: var(--interactive-secondary);
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.primary-btn:active:not(:disabled),
#submit-answer:active:not(:disabled) {
    transform: translateY(0);
    box-shadow: none;
}

.primary-btn:disabled,
#submit-answer:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    background-color: var(--bg-tertiary);
    border-color: var(--border-color);
    color: var(--text-secondary);
}

/* Specific button styles */
#hint-btn {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

#next-btn {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.back-to-subjects {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    margin-top: 10px;
}

.back-to-subjects:hover {
    background: var(--interactive-primary);
    color: var(--bg-primary);
}

/* Subject topic buttons (algebra, calculus, mechanics, etc.) */
.subject-btn {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 12px 20px;
    margin: 5px;
    border-radius: 6px;
    transition: all 0.2s ease;
}

.subject-btn:hover {
    background: var(--interactive-primary);
    color: var(--bg-primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.subject-selection h2 {
    color: var(--section-header);
    margin-bottom: 10px;
}

/* Theme Selector */
.theme-selector {
    position: relative;
}

.theme-selector select {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 8px 12px;
    font-family: var(--font-family);
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s ease;
    min-width: 150px;
}

.theme-selector select:hover {
    border-color: var(--primary-color);
}

.theme-selector select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.1);
}

/* Subject Selection */
.subject-selection {
    background: var(--bg-secondary);
    border-radius: 8px;
    padding: 20px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.subject-categories {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.category {
    background: var(--bg-tertiary);
    padding: 15px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
}

.category h3 {
    margin-bottom: 10px;
    font-weight: 600;
}

/* Mathematics section */
.category:first-child h3 {
    color: var(--math-color);
}

/* Physics section */
.category:last-child h3 {
    color: var(--physics-color);
}

.subject-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 10px;
}

button, .subject-btn {
    background-color: var(--interactive-primary);
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    font-family: var(--font-family);
    transition: all 0.2s;
}

button:hover {
    opacity: 0.8;
}


/* Problem Container */
.problem-container {
    background: var(--card-background);
    border-radius: 8px;
    padding: 25px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.problem-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}

.problem-text {
    font-size: 18px;
    margin: 25px 0;
    min-height: 100px;
    line-height: 1.8;
}

/* Answer Section */
.answer-section {
    display: flex;
    gap: 10px;
    margin: 25px 0;
}

#answer-input {
    flex: 1;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    font-size: 16px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-family: var(--font-family);
    transition: all 0.2s ease;
}

#answer-input:focus {
    outline: none;
    border-color: var(--interactive-primary);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

/* Feedback */
.feedback {
    padding: 15px 20px;
    border-radius: 6px;
    margin: 20px 0;
    font-size: 16px;
    transition: all 0.3s ease;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
}

.feedback-message {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.feedback-message.correct {
    color: var(--success);
    animation: correctAnswer 0.5s ease;
}

.feedback-message.incorrect {
    color: var(--error);
}

.correct-answer {
    margin: 12px 0;
    padding: 12px 15px;
    background: var(--bg-secondary);
    border-radius: 4px;
    border-left: 4px solid var(--border-color);
    color: var(--text-primary);
}

.correct-answer .answer {
    font-weight: 600;
    color: var(--success);
}

.solution {
    margin-top: 15px;
    padding: 15px;
    background: var(--bg-secondary);
    border-radius: 6px;
    border-left: 4px solid var(--interactive-secondary);
    color: var(--text-primary);
}

.solution-title {
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-accent);
}

.solution-content {
    line-height: 1.7;
    color: var(--text-primary);
}

.solution-content .katex {
    font-size: 1.1em;
}

@keyframes correctAnswer {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* Answer input styles */
#answer-input {
    flex: 1;
    padding: 12px 15px;
    border: 2px solid #ced4da;
    border-radius: 4px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

#answer-input:focus {
    outline: none;
    border-color: #80bdff;
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
}

#answer-input:disabled {
    background-color: #e9ecef;
    cursor: not-allowed;
}

.latex-display {
    display: block;
    margin: 1em 0;
    text-align: center;
}

/* Navigation Buttons */
.navigation-buttons {
    display: flex;
    justify-content: space-between;
    margin-top: 25px;
    gap: 15px;
}

.nav-group {
    display: flex;
    gap: 10px;
}

.primary-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.primary-btn:hover {
    background-color: #2980b9;
}

.secondary-btn {
    background-color: #f8f9fa;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
    padding: 9px 15px;
    border-radius: 4px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s;
}

.secondary-btn:hover {
    background-color: #e9ecef;
}

#submit-answer {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.2s;
    margin-left: 10px;
}

#submit-answer:hover {
    background-color: #2980b9;
}

#submit-answer:disabled {
    background-color: #bdc3c7;
    cursor: not-allowed;
}

/* Difficulty Meter */
.difficulty-meter {
    display: flex;
    align-items: center;
    gap: 10px;
}

.difficulty-bar {
    width: 150px;
    height: 10px;
    background-color: #e9ecef;
    border-radius: 5px;
    overflow: hidden;
}

.difficulty-level {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, #2ecc71, #f1c40f, #e74c3c);
    transition: width 0.3s ease;
}

/* Progress Container */
.progress-container {
    background: var(--bg-secondary);
    border-radius: 8px;
    padding: 20px;
    box-shadow: var(--shadow);
}

.progress-container h3 {
    color: var(--section-header);
    margin-bottom: 15px;
}

#progress-stats {
    display: flex;
    justify-content: space-around;
    margin-top: 15px;
    text-align: center;
}

#progress-stats > div {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
}

/* Progress stat labels */
#progress-stats > div:first-child {
    color: var(--data-success);
}

#progress-stats > div:nth-child(2) {
    color: var(--data-error);
}

#progress-stats > div:last-child {
    color: var(--data-warning);
}

/* Progress stat numbers */
#correct-count {
    color: var(--data-primary);
    font-weight: bold;
    font-size: 1.2em;
}

#incorrect-count {
    color: var(--data-primary);
    font-weight: bold;
    font-size: 1.2em;
}

#streak-count {
    color: var(--data-primary);
    font-weight: bold;
    font-size: 1.2em;
}

/* Tab Navigation */
.tab-navigation {
    display: flex;
    background: var(--bg-secondary);
    border-radius: 8px 8px 0 0;
    box-shadow: var(--shadow);
    margin-bottom: 0;
}

.tab-btn {
    flex: 1;
    padding: 15px 20px;
    background: var(--bg-secondary);
    border: none;
    color: var(--text-primary);
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: center;
    opacity: 0.9;
    border-bottom: 3px solid transparent;
    font-weight: 400;
}

.tab-btn:hover {
    background: var(--bg-tertiary);
    color: var(--nav-primary);
    opacity: 0.9;
}

.tab-btn.active {
    background: var(--bg-secondary);
    color: var(--nav-primary);
    border-bottom: 3px solid var(--nav-primary);
}

/* Tab Content */
.tab-content {
    background: var(--bg-secondary);
    border-radius: 0 0 8px 8px;
    box-shadow: var(--shadow);
    min-height: 500px;
}

.tab-panel {
    padding: 30px;
    display: none;
}

.tab-panel.active {
    display: block;
}

.tab-panel h2 {
    color: var(--section-header);
    margin-bottom: 20px;
    font-weight: 600;
}

/* Form Styles */
.question-form, .login-form {
    max-width: 600px;
    margin: 20px 0;
}

/* Question Type Toggle */
#question-type {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 15px;
}

/* Multiple Choice Inputs */
.mc-option-input {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
    padding: 8px 12px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    transition: all 0.2s ease;
}

.mc-option-input:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--nav-primary);
}

.mc-option-input input[type="radio"] {
    margin-right: 10px;
    width: 18px;
    height: 18px;
    min-width: 18px;
    cursor: pointer;
}

.mc-option-input input[type="text"] {
    flex: 1;
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color 0.2s ease;
}

.mc-option-input input[type="text"]:focus {
    outline: none;
    border-color: var(--nav-primary);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

/* Form group specific styles */
#short-answer-group,
#multiple-choice-group {
    margin-bottom: 20px;
    transition: all 0.3s ease;
}

/* Hide/show form sections based on question type */
#question-type[value="short-answer"] ~ #short-answer-group {
    display: block;
}

#question-type[value="multiple-choice"] ~ #multiple-choice-group {
    display: block;
}

/* Multiple Choice Styles */
.mc-section {
    margin: 20px 0;
}

.mc-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin: 20px 0;
}

.mc-option {
    display: flex;
    align-items: center;
    padding: 14px 18px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.mc-option:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--nav-primary);
}

.mc-option input[type="radio"] {
    margin-right: 12px;
    cursor: pointer;
    width: 18px;
    height: 18px;
    min-width: 18px;
}

.mc-option label {
    cursor: pointer;
    flex-grow: 1;
    margin: 0;
    font-size: 1rem;
    color: var(--text-primary);
    line-height: 1.5;
}

.mc-option input[type="radio"]:checked + label {
    font-weight: 500;
    color: var(--nav-primary);
}

.mc-option input[type="radio"]:checked {
    accent-color: var(--nav-primary);
}

/* Selected state */
.mc-option.selected {
    background-color: var(--bg-tertiary);
    border-color: var(--nav-primary);
    box-shadow: 0 0 0 1px var(--nav-primary);
}

/* Correct/Incorrect feedback */
.mc-option.correct {
    background-color: rgba(16, 185, 129, 0.1);
    border-color: var(--success);
}

.mc-option.incorrect {
    background-color: rgba(239, 68, 68, 0.1);
    border-color: var(--error);
}

.mc-submit-btn {
    display: block;
    width: 100%;
    padding: 14px 20px;
    background-color: var(--nav-primary);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    margin-top: 10px;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.mc-submit-btn:hover:not(:disabled) {
    background-color: var(--nav-primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.mc-submit-btn:active:not(:disabled) {
    transform: translateY(0);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.mc-submit-btn:disabled {
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    cursor: not-allowed;
    opacity: 0.7;
}

/* Dark theme adjustments */
[data-theme*="dark"] .mc-option {
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

[data-theme*="dark"] .mc-option:hover {
    background-color: var(--bg-tertiary);
}

[data-theme*="dark"] .mc-option input[type="radio"] {
    filter: brightness(1.2);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
    color: var(--text-color);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 14px;
    font-family: var(--font-family);
    background: var(--input-background);
    color: var(--text-color);
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.1);
}

.form-group textarea {
    min-height: 100px;
    resize: vertical;
}

/* Rating Info */
.rating-info {
    background: var(--hover-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 20px;
    margin-bottom: 25px;
}

.rating-info h3 {
    color: var(--section-header-color);
    margin-bottom: 15px;
}

.rating-info ul {
    list-style: none;
    padding: 0;
}

.rating-info li {
    padding: 5px 0;
    border-bottom: 1px solid #e9ecef;
}

.rating-info li:last-child {
    border-bottom: none;
}

/* Tags Selector */
.tags-selector-container {
    position: relative;
}

.tags-search-box {
    position: relative;
}

.tags-dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: white;
    border: 1px solid var(--border-color);
    border-top: none;
    border-radius: 0 0 4px 4px;
    max-height: 200px;
    overflow-y: auto;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.tag-option {
    padding: 8px 12px;
    cursor: pointer;
    border-bottom: 1px solid #f0f0f0;
    font-size: 14px;
    transition: background-color 0.2s;
}

.tag-option:hover {
    background-color: #f8f9fa;
}

.tag-option:last-child {
    border-bottom: none;
}

.tag-option.selected {
    background-color: var(--primary-color);
    color: white;
}

.selected-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px;
    min-height: 32px;
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: #f8f9fa;
}

.selected-tag {
    display: inline-flex;
    align-items: center;
    background: var(--primary-color);
    color: white;
    padding: 4px 8px;
    border-radius: 16px;
    font-size: 12px;
    gap: 6px;
}

.selected-tag .remove-tag {
    cursor: pointer;
    font-weight: bold;
    font-size: 14px;
    line-height: 1;
    padding: 0 2px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transition: background-color 0.2s;
}

.selected-tag .remove-tag:hover {
    background: rgba(255, 255, 255, 0.5);
}

.no-tags-message {
    color: #6c757d;
    font-style: italic;
    font-size: 14px;
    padding: 4px;
}

/* Pending Questions */
.question-card {
    background: var(--hover-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 20px;
    margin-bottom: 20px;
}

.question-card h4 {
    color: var(--section-header-color);
    margin-bottom: 10px;
}

.question-meta {
    display: flex;
    gap: 20px;
    margin: 10px 0;
    font-size: 14px;
    color: #6c757d;
}

.question-actions {
    display: flex;
    gap: 10px;
    margin-top: 15px;
}

.approve-btn {
    background-color: var(--secondary-color);
}

.approve-btn:hover {
    background-color: #27ae60;
}

.deny-btn {
    background-color: var(--error-color);
}

.deny-btn:hover {
    background-color: #c0392b;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* Responsive Design */
@media (max-width: 768px) {
    .subject-categories {
        grid-template-columns: 1fr;
    }
    
    .answer-section {
        flex-direction: column;
    }
    
    button, #answer-input, .subject-btn {
        width: 100%;
    }
    
    .navigation-buttons {
        flex-direction: column;
        gap: 10px;
    }
    
    .tab-navigation {
        flex-direction: column;
    }
    
    .tab-btn {
        border-radius: 0;
        border-bottom: 1px solid var(--border-color);
    }
    
    .tab-btn:first-child {
        border-radius: 8px 8px 0 0;
    }
    
    .tab-btn:last-child {
        border-bottom: none;
    }
    
    .tab-btn.active {
        border-bottom: 3px solid var(--primary-color);
    }
    
    .question-meta {
        flex-direction: column;
        gap: 5px;
    }
    
    .question-actions {
        flex-direction: column;
    }
    
    .selected-tags {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .selected-tag {
        margin-bottom: 4px;
    }
    
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    
    .theme-selector {
        order: -1;
        margin-bottom: 20px;
    }
    
    .theme-selector select {
        min-width: 120px;
        font-size: 12px;
    }
}