/* ============================================
   타이핑데몬헌터 UI 리디자인
   Design System & CSS Variables
   ============================================ */

:root {
    /* 배경색 */
    --bg-gradient-start: #0a0a0f;
    --bg-gradient-mid: #1a1a2e;
    --bg-gradient-end: #16213e;
    --bg-header: linear-gradient(to right, #1a1a2e, #16213e, #0f3460);

    --card-bg-primary: #161b22;
    --card-bg-dark: #0d1117;
    --card-bg-black: #000000;
    --card-border: #30363d;
    --card-border-dark: #21262d;

    /* 텍스트 색상 */
    --text-primary: #c9d1d9;
    --text-bright: #e6edf3;
    --text-muted: #8b949e;
    --text-dimmed: #94a3b8;
    --text-white: #ffffff;

    /* 포인트 색상 (그라데이션) */
    --accent-blue: #60a5fa;
    --accent-purple: #a78bfa;
    --accent-pink: #ec4899;
    --accent-gradient: linear-gradient(to right, #60a5fa, #a78bfa, #ec4899);

    /* 타이머/WPM 박스 테두리 그라데이션 */
    --timer-gradient: linear-gradient(to bottom right, #1e3a8a, #7c3aed, #db2777);

    /* 상태 색상 */
    --success-green: #4ade80;
    --success-green-dark: #22c55e;
    --success-green-darker: #16a34a;

    --error-red: #ff6b6b;
    --error-red-bg: rgba(255, 107, 107, 0.2);

    --warning-yellow: #f0ad4e;
    --warning-yellow-alt: #fbbf24;

    /* 진행률 색상 */
    --progress-low: #60a5fa;
    --progress-mid: #fbbf24;
    --progress-high: #4ade80;

    /* 구문 강조 색상 */
    --syntax-keyword: #C586C0;
    --syntax-string: #CE9178;
    --syntax-function: #DCDCAA;
    --syntax-type: #4EC9B0;
    --syntax-number: #B5CEA8;
    --syntax-boolean: #569CD6;
    --syntax-default: #9cdcfe;
    --syntax-comment: #6A9955;

    /* 폰트 */
    --font-ui: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-code: 'Consolas', 'Monaco', 'Courier New', monospace;

    /* 폰트 크기 */
    --text-xs: 12px;
    --text-sm: 14px;
    --text-base: 16px;
    --text-lg: 18px;
    --text-xl: 20px;
    --text-2xl: 22px;
    --text-3xl: 24px;
    --text-4xl: 32px;
    --text-5xl: 36px;

    /* 폰트 굵기 */
    --font-normal: 400;
    --font-medium: 500;
    --font-semibold: 600;
    --font-bold: 700;

    /* 간격 */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 12px;
    --spacing-lg: 16px;
    --spacing-xl: 20px;
    --spacing-2xl: 24px;
    --spacing-3xl: 32px;
    --spacing-4xl: 48px;

    /* 레이아웃 */
    --max-width-main: 1200px;
    --max-width-header: 1400px;
    --max-width-completion: 900px;

    /* border-radius */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 10px;
    --radius-xl: 12px;
    --radius-full: 9999px;

    /* 그림자 */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 12px 48px rgba(0, 0, 0, 0.6);
    --shadow-inner: inset 0 2px 4px rgba(0, 0, 0, 0.3);

    /* 글로우 효과 */
    --glow-blue: 0 0 12px rgba(96, 165, 250, 0.5);
    --glow-green: 0 0 8px rgba(74, 222, 128, 0.5);
    --glow-purple: 0 0 12px rgba(167, 139, 250, 0.4);
}

/* ============================================
   Reset and Base Styles
   ============================================ */

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

body {
    font-family: var(--font-ui);
    min-height: 100vh;
    background: linear-gradient(to bottom right, var(--bg-gradient-start), var(--bg-gradient-mid), var(--bg-gradient-end));
    color: var(--text-primary);
    transition: background 0.3s ease, color 0.3s ease;
}

/* ============================================
   Dark Theme (Default)
   ============================================ */

body.theme-dark {
    background: linear-gradient(to bottom right, var(--bg-gradient-start), var(--bg-gradient-mid), var(--bg-gradient-end));
    color: var(--text-primary);
}

/* Light Theme */
body.theme-light {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #24292f;
}

body.theme-light .container {
    background: #ffffff;
}

/* ============================================
   Sticky Header
   ============================================ */

.sticky-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--bg-header);
    border-bottom: 1px solid var(--card-border);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
    padding: var(--spacing-xl) var(--spacing-2xl);
}

.sticky-header.scrolled {
    box-shadow: 0 12px 48px rgba(0, 0, 0, 0.6);
}

.header-container {
    max-width: var(--max-width-header);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-lg);
}

/* Header Left - Title */
.header-left {
    flex-shrink: 0;
}

.header-left .title {
    font-size: var(--text-3xl);
    font-weight: var(--font-bold);
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    white-space: nowrap;
    margin: 0;
}

/* Header Center - Controls */
.header-center {
    display: flex;
    align-items: center;
    gap: 15px;
    flex-wrap: wrap;
    flex: 1;
    justify-content: center;
}

.control-group {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.control-group label {
    font-weight: var(--font-semibold);
    font-size: var(--text-sm);
    color: var(--text-muted);
}

/* Select Dropdowns */
.select {
    height: 44px;
    padding: 0 var(--spacing-lg);
    background: var(--card-bg-primary);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: var(--text-base);
    cursor: pointer;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.select:hover {
    border-color: var(--accent-blue);
}

.select:focus {
    outline: none;
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 4px rgba(96, 165, 250, 0.2);
}

.select option {
    background: var(--card-bg-dark);
    color: var(--text-primary);
}

#language-select { width: 144px; }
#difficulty-select { width: 128px; }
#chapter-select { width: 112px; }

/* Buttons */
.btn {
    height: 44px;
    padding: 0 var(--spacing-xl);
    background: var(--card-bg-primary);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn:hover {
    background: var(--card-border);
}

.btn-restart {
    background: linear-gradient(to right, var(--success-green), var(--success-green-dark));
    border: none;
    color: var(--card-bg-black);
    font-weight: var(--font-bold);
    box-shadow: 0 4px 12px rgba(74, 222, 128, 0.3);
}

.btn-restart:hover {
    background: linear-gradient(to right, var(--success-green-dark), var(--success-green-darker));
    box-shadow: 0 6px 20px rgba(74, 222, 128, 0.5);
}

/* Theme Toggle Button */
.theme-toggle-btn {
    padding: 0 var(--spacing-md);
    min-width: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-icon::before {
    content: '☀️';
    font-size: var(--text-lg);
}

body.theme-light .theme-icon::before {
    content: '🌙';
}

/* Header Right - Timer & WPM */
.header-right {
    flex-shrink: 0;
}

.timer-display {
    position: relative;
    padding: 2px;
    background: var(--timer-gradient);
    border-radius: var(--radius-xl);
    animation: pulse-glow 2s ease-in-out infinite;
}

.timer-display-inner {
    background: #0f172a;
    padding: var(--spacing-lg) var(--spacing-3xl);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-3xl);
}

.timer-item {
    text-align: center;
}

.timer-sublabel {
    font-size: var(--text-xs);
    color: var(--text-dimmed);
    font-weight: var(--font-semibold);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
}

.timer {
    font-size: var(--text-xl);
    font-family: var(--font-code);
    font-weight: var(--font-bold);
    color: var(--text-white);
}

.timer-label {
    font-size: var(--text-xs);
    color: var(--text-dimmed);
    font-weight: var(--font-semibold);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
}

#wpm {
    font-size: var(--text-xl);
    font-family: var(--font-code);
    font-weight: var(--font-bold);
    background: linear-gradient(to right, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.timer-divider {
    width: 1px;
    height: 48px;
    background: linear-gradient(to bottom, transparent, var(--accent-blue), transparent);
}

@keyframes pulse-glow {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/* ============================================
   Header Spacer
   ============================================ */

.header-spacer {
    height: 100px;
}

/* ============================================
   Container
   ============================================ */

.container {
    max-width: var(--max-width-main);
    margin: 0 auto;
    padding: var(--spacing-3xl);
    position: relative;
}

/* ============================================
   Lesson Card (Collapsible)
   ============================================ */

.lesson-section {
    background: linear-gradient(to bottom right, var(--bg-gradient-mid), var(--bg-gradient-end));
    border: 1px solid var(--card-border);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    margin-bottom: var(--spacing-2xl);
    animation: fadeInDown 0.7s ease-out;
}

.lesson-section > h3 {
    padding: var(--spacing-xl) var(--spacing-2xl);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: var(--text-3xl);
    font-weight: var(--font-bold);
    color: var(--text-white);
    margin: 0;
    transition: background 0.2s ease;
}

.lesson-section > h3:hover {
    background: rgba(28, 33, 40, 0.5);
}

#lesson-description {
    padding: 0 var(--spacing-2xl) var(--spacing-2xl);
    color: var(--text-dimmed);
    font-size: var(--text-base);
    line-height: 1.8;
}

/* Subsection boxes within lesson content */
.lesson-intro,
.lesson-why,
.lesson-example,
.lesson-key {
    background-color: rgba(255, 255, 255, 0.05);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--accent-blue);
}

.lesson-intro { border-left-color: var(--accent-blue); }
.lesson-why { border-left-color: var(--warning-yellow); }
.lesson-example { border-left-color: var(--success-green); }
.lesson-key { border-left-color: var(--accent-purple); }

.lesson-section h4 {
    color: var(--text-primary);
    font-size: var(--text-lg);
    font-weight: var(--font-semibold);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.lesson-section p {
    color: var(--text-muted);
    line-height: 1.8;
    font-size: 15px;
    margin: 0;
}

.lesson-example pre {
    background-color: var(--card-bg-primary);
    padding: 15px;
    border-radius: var(--radius-sm);
    overflow-x: auto;
    margin-top: 10px;
}

.lesson-example code {
    color: var(--text-primary);
    font-family: var(--font-code);
    font-size: var(--text-sm);
    line-height: 1.6;
}

.lesson-key ul {
    list-style: none;
    padding: 0;
    margin: 10px 0 0 0;
}

.lesson-key li {
    color: var(--text-muted);
    padding: var(--spacing-sm) 0;
    padding-left: 25px;
    position: relative;
    line-height: 1.6;
}

.lesson-key li::before {
    content: "▸";
    position: absolute;
    left: 0;
    color: var(--accent-blue);
    font-weight: bold;
}

.lesson-key code {
    background-color: rgba(110, 118, 129, 0.4);
    color: #79c0ff;
    padding: 2px 6px;
    border-radius: 3px;
    font-family: var(--font-code);
    font-size: 13px;
}

.lesson-section .hints {
    color: var(--text-muted);
    font-style: italic;
    margin-top: 10px;
    padding: 10px;
    background-color: #1a1a1a;
    border-radius: 4px;
    font-size: var(--text-sm);
    border-left: 3px solid var(--accent-blue);
}

/* ============================================
   Code Display Card
   ============================================ */

.text-container {
    margin-bottom: var(--spacing-2xl);
    position: relative;
}

.section-label {
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    background: linear-gradient(to right, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-xl) var(--spacing-2xl);
    border-bottom: 1px solid var(--card-border);
}

.text-container:first-of-type {
    background: var(--card-bg-primary);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-xl);
    position: relative;
}

/* Left gradient bar */
.text-container:first-of-type::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: linear-gradient(to bottom, var(--accent-blue), var(--accent-purple), var(--accent-pink));
}

.text-display {
    font-family: var(--font-code);
    font-size: var(--text-lg);
    line-height: 1.6;
    white-space: pre-wrap;
    word-wrap: break-word;
    position: relative;
}

.original-text {
    margin: var(--spacing-2xl);
    padding: var(--spacing-3xl);
    background: var(--card-bg-dark);
    border: 1px solid var(--card-border-dark);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-inner);
    overflow-x: auto;
    color: var(--text-primary);
}

/* ============================================
   Input Card
   ============================================ */

.text-container:nth-of-type(2) {
    background: var(--card-bg-primary);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-xl);
    position: relative;
}

/* Left gradient bar (animated) */
.text-container:nth-of-type(2)::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: linear-gradient(to bottom, var(--success-green), #22d3ee, var(--accent-blue));
    animation: pulse 2s ease-in-out infinite;
}

.text-container:nth-of-type(2) .section-label {
    background: linear-gradient(to right, var(--success-green), #22d3ee);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.user-input {
    margin: var(--spacing-2xl);
    padding: var(--spacing-3xl);
    background: var(--card-bg-dark);
    border: 2px solid var(--card-border);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-inner);
    min-height: 192px;
    transition: all 0.2s ease;
}

.user-input:focus-within {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 4px rgba(96, 165, 250, 0.3);
}

/* ============================================
   Progress Display
   ============================================ */

.progress-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 0 var(--spacing-2xl) var(--spacing-lg);
}

.progress-label {
    font-size: var(--text-base);
    color: var(--text-muted);
    font-weight: var(--font-medium);
}

.progress-percentage {
    font-size: var(--text-3xl);
    font-weight: var(--font-bold);
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.3));
}

.progress-percentage.low { color: var(--progress-low); }
.progress-percentage.mid { color: var(--progress-mid); }
.progress-percentage.high { color: var(--progress-high); }

.char-count {
    font-size: var(--text-lg);
    color: var(--text-muted);
    font-weight: var(--font-medium);
}

.char-count .current {
    color: var(--accent-blue);
    font-weight: var(--font-bold);
}

.progress-bar-container {
    margin: 0 var(--spacing-2xl) var(--spacing-2xl);
    height: 12px;
    background: var(--card-bg-dark);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-full);
    overflow: hidden;
    box-shadow: var(--shadow-inner);
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(to right, var(--accent-blue), var(--accent-purple), var(--accent-pink));
    border-radius: var(--radius-full);
    transition: width 0.3s ease;
    box-shadow: var(--glow-blue);
}

/* ============================================
   Character Styles
   ============================================ */

.char {
    position: relative;
}

.char.current {
    background: linear-gradient(to right, var(--accent-blue), var(--accent-purple));
    color: var(--text-white);
    border-radius: 2px;
    box-shadow: var(--glow-blue);
    animation: pulse 1s ease-in-out infinite;
}

.char.completed {
    color: var(--text-muted);
    opacity: 0.6;
}

.char.correct {
    color: var(--success-green);
}

.char.incorrect {
    color: var(--error-red);
    background: var(--error-red-bg);
    border-radius: 2px;
}

.char-input {
    color: var(--text-primary);
}

.char-input.correct {
    color: var(--success-green);
}

.char-input.incorrect {
    color: var(--error-red);
    background: var(--error-red-bg);
    font-weight: var(--font-bold);
}

/* Typed text and cursor container */
.typed-text {
    display: inline;
    white-space: pre-wrap;
    word-wrap: break-word;
}

/* Cursor */
.cursor {
    display: inline-block;
    width: 2px;
    height: var(--text-xl);
    background: linear-gradient(to bottom, var(--accent-blue), var(--accent-purple));
    animation: blink 1s ease-in-out infinite;
    box-shadow: var(--glow-blue);
    vertical-align: text-bottom;
    margin-left: 1px;
    pointer-events: none;
}

@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/* Hidden Input */
.hidden-input {
    position: absolute;
    opacity: 0;
    z-index: -1;
    pointer-events: none;
}

/* ============================================
   Expected Output / Terminal Card
   ============================================ */

.output-section {
    background: var(--card-bg-primary);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    margin-top: var(--spacing-xl);
    animation: slideInUp 0.3s ease-out;
}

.output-section h4 {
    padding: var(--spacing-xl) var(--spacing-2xl);
    border-bottom: 1px solid var(--card-border);
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    background: linear-gradient(to right, var(--warning-yellow-alt), #f59e0b);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin: 0;
}

.terminal-output {
    margin: var(--spacing-2xl);
    padding: var(--spacing-3xl);
    background: var(--card-bg-black);
    border: 1px solid #1a1a1a;
    border-radius: var(--radius-xl);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.8);
}

.terminal-output pre {
    font-family: var(--font-code);
    font-size: var(--text-lg);
    line-height: 1.6;
    margin: 0;
}

.terminal-prompt {
    color: #58a6ff;
    font-weight: bold;
}

.terminal-command {
    color: var(--text-primary);
    margin-left: 5px;
}

.terminal-result {
    color: var(--success-green);
    text-shadow: 0 0 4px rgba(74, 222, 128, 0.3);
}

/* ============================================
   Syntax Highlighting
   ============================================ */

body.theme-dark .syntax-keyword { color: var(--syntax-keyword); }
body.theme-dark .syntax-function { color: var(--syntax-function); }
body.theme-dark .syntax-string { color: var(--syntax-string); }
body.theme-dark .syntax-number { color: var(--syntax-number); }
body.theme-dark .syntax-type { color: var(--syntax-type); }
body.theme-dark .syntax-comment { color: var(--syntax-comment); }
body.theme-dark .syntax-operator { color: #D4D4D4; }

body.theme-light .syntax-keyword,
body.theme-light .syntax-function,
body.theme-light .syntax-string,
body.theme-light .syntax-number,
body.theme-light .syntax-type,
body.theme-light .syntax-comment,
body.theme-light .syntax-operator {
    color: inherit;
}

/* ============================================
   Completion Screen
   ============================================ */

.completion-screen {
    min-height: 100vh;
    background: linear-gradient(to bottom right, #1e1e1e, var(--card-bg-dark));
    color: var(--text-primary);
    padding: var(--spacing-3xl) var(--spacing-lg);
}

.completion-screen > * {
    max-width: var(--max-width-completion);
    margin-left: auto;
    margin-right: auto;
}

/* Completion Header */
.completion-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
    animation: fadeInDown 0.7s ease-out;
}

/* Success Icon Wrapper */
.success-icon-wrapper {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
    background: rgba(74, 222, 128, 0.1);
    border-radius: 50%;
    margin-bottom: var(--spacing-sm);
    animation: pulse 2s ease-in-out infinite;
}

.success-icon {
    width: 48px;
    height: 48px;
    color: var(--success-green);
}

.completion-header h1 {
    font-size: var(--text-5xl);
    font-weight: var(--font-bold);
    color: var(--success-green);
    letter-spacing: -0.02em;
    animation: shimmer 2s ease-in-out infinite;
    margin-bottom: var(--spacing-sm);
}

.completion-header h2 {
    font-size: var(--text-xl);
    color: var(--text-muted);
    font-weight: var(--font-normal);
    margin-top: var(--spacing-md);
}

@keyframes shimmer {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-16px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(16px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* Stats Card */
.stats-card {
    background: linear-gradient(to bottom right, #1f6feb, #8b5cf6);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-3xl);
    margin-bottom: var(--spacing-2xl);
    box-shadow: var(--shadow-xl);
    animation: fadeInUp 0.7s ease-out 0.1s both;
}

.stats-card h3 {
    font-size: var(--text-3xl);
    font-weight: var(--font-bold);
    color: var(--text-white);
    margin-bottom: var(--spacing-2xl);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-2xl);
}

.stat-item {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(8px);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    text-align: center;
}

.stat-value {
    font-size: var(--text-4xl);
    font-family: var(--font-code);
    font-weight: var(--font-bold);
    color: var(--text-white);
    margin-bottom: var(--spacing-sm);
}

.stat-value.excellent {
    color: var(--success-green);
    text-shadow: var(--glow-green);
}

.stat-sublabel {
    font-size: var(--text-xs);
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: var(--spacing-sm);
}

.stat-label {
    font-size: var(--text-sm);
    color: rgba(255, 255, 255, 0.8);
}

/* Learning Card */
.learning-card {
    background: var(--card-bg-primary);
    border: 1px solid var(--card-border);
    border-left: 4px solid var(--warning-yellow);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
    box-shadow: var(--shadow-lg);
    animation: fadeInUp 0.7s ease-out 0.2s both;
}

.learning-card h3 {
    font-size: var(--text-xl);
    font-weight: var(--font-bold);
    color: var(--text-white);
    margin-bottom: var(--spacing-2xl);
}

.concepts-section,
.cando-section {
    margin-bottom: var(--spacing-2xl);
}

.concepts-section:last-child,
.cando-section:last-child {
    margin-bottom: 0;
}

.concepts-section h4 {
    font-size: var(--text-lg);
    font-weight: var(--font-semibold);
    color: var(--warning-yellow);
    margin-bottom: var(--spacing-md);
}

.cando-section h4 {
    font-size: var(--text-lg);
    font-weight: var(--font-semibold);
    color: var(--success-green);
    margin-bottom: var(--spacing-md);
}

.learning-card ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.learning-card li {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    padding: var(--spacing-sm) 0;
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--text-bright);
}

.learning-card li::before {
    content: "•";
    color: var(--accent-blue);
    font-weight: bold;
    flex-shrink: 0;
}

.concepts-section li::before {
    color: var(--warning-yellow);
}

.cando-section li::before {
    color: var(--success-green);
}

/* Code Result Card */
.code-card {
    background: var(--card-bg-dark);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
    box-shadow: var(--shadow-lg);
    animation: fadeInUp 0.7s ease-out 0.3s both;
}

.code-card h3 {
    font-size: var(--text-lg);
    font-weight: var(--font-bold);
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
}

.code-card pre {
    background: rgba(0, 0, 0, 0.5);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    overflow-x: auto;
    font-family: var(--font-code);
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--text-primary);
    margin: 0;
    white-space: pre-wrap;
    word-wrap: break-word;
}

/* Result Card (Terminal) */
.result-card {
    background: var(--card-bg-black);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
    box-shadow: var(--shadow-lg);
    animation: fadeInUp 0.7s ease-out 0.4s both;
}

.result-card h3 {
    font-size: var(--text-lg);
    font-weight: var(--font-bold);
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
}

.completion-terminal {
    font-family: var(--font-code);
    font-size: var(--text-base);
    line-height: 1.6;
}

.completion-terminal .terminal-prompt {
    color: #58a6ff;
    font-weight: bold;
}

.completion-terminal .terminal-command {
    color: var(--text-primary);
    margin-left: 5px;
}

.completion-terminal .terminal-result {
    color: var(--success-green);
    text-shadow: 0 0 4px rgba(74, 222, 128, 0.3);
}

/* Completion Buttons */
.completion-buttons {
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    animation: fadeInUp 0.7s ease-out 0.5s both;
}

.btn-retry,
.btn-next,
.btn-home {
    padding: var(--spacing-md) var(--spacing-2xl);
    font-size: var(--text-base);
    font-weight: var(--font-bold);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all 0.2s ease;
}

/* Ghost Buttons */
.btn-retry,
.btn-home {
    background: transparent;
    border: 1px solid var(--card-border);
    color: var(--text-primary);
}

.btn-retry:hover,
.btn-home:hover {
    background: var(--card-bg-primary);
    box-shadow: 0 0 12px rgba(88, 166, 255, 0.2);
}

/* Primary Button */
.btn-next {
    background: linear-gradient(to right, #238636, #2ea043);
    border: none;
    color: var(--text-white);
    transform: scale(1.05);
    box-shadow: 0 4px 16px rgba(35, 134, 54, 0.4);
}

.btn-next:hover {
    background: linear-gradient(to right, #2ea043, #238636);
    box-shadow: 0 6px 24px rgba(46, 160, 67, 0.5);
}

.btn-next:disabled {
    background: #21262d;
    color: #484f58;
    cursor: not-allowed;
    transform: scale(1);
    box-shadow: none;
}

/* ============================================
   Light Theme Overrides
   ============================================ */

body.theme-light .sticky-header {
    background: linear-gradient(135deg, #f6f8fa 0%, #ffffff 100%);
    border-bottom-color: #d0d7de;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

body.theme-light .header-left .title {
    background: linear-gradient(to right, #0969da, #8250df);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

body.theme-light .control-group label {
    color: #57606a;
}

body.theme-light .select {
    background: white;
    border-color: #d0d7de;
    color: #24292f;
}

body.theme-light .select:hover {
    border-color: #0969da;
}

body.theme-light .select:focus {
    border-color: #0969da;
    box-shadow: 0 0 0 3px rgba(9, 105, 218, 0.1);
}

body.theme-light .select option {
    background: white;
    color: #24292f;
}

body.theme-light .btn {
    background: #f6f8fa;
    border-color: #d0d7de;
    color: #24292f;
}

body.theme-light .btn:hover {
    background: #eaeef2;
}

body.theme-light .btn-restart {
    background: linear-gradient(to right, #2da44e, #238636);
}

body.theme-light .timer-display {
    background: linear-gradient(135deg, #0969da 0%, #0550ae 100%);
}

body.theme-light .timer-display-inner {
    background: #f0f6fc;
}

body.theme-light .timer {
    color: #24292f;
}

body.theme-light #wpm {
    background: linear-gradient(to right, #0969da, #8250df);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

body.theme-light .section-label {
    color: #0969da;
}

body.theme-light .text-container:first-of-type,
body.theme-light .text-container:nth-of-type(2) {
    background: #ffffff;
    border-color: #d0d7de;
}

body.theme-light .original-text,
body.theme-light .user-input {
    background: #f6f8fa;
    border-color: #d0d7de;
    color: #24292f;
}

body.theme-light .char.current {
    background: rgba(9, 105, 218, 0.2);
    color: #0969da;
}

body.theme-light .char.completed {
    color: #8c959f;
}

body.theme-light .char.correct {
    color: #1a7f37;
}

body.theme-light .char.incorrect {
    color: #cf222e;
    background: rgba(207, 34, 46, 0.1);
}

body.theme-light .cursor {
    background: linear-gradient(to bottom, #0969da, #8250df);
}

body.theme-light .lesson-section {
    background: linear-gradient(135deg, #f6f8fa 0%, #ffffff 100%);
    border-left-color: #0969da;
}

body.theme-light .lesson-section > h3 {
    color: #24292f;
}

body.theme-light #lesson-description {
    color: #57606a;
}

body.theme-light .output-section {
    background-color: #ffffff;
    border-color: #d0d7de;
}

body.theme-light .terminal-output {
    background-color: #f6f8fa;
    color: #24292f;
}

body.theme-light .terminal-result {
    color: #0969da;
}

/* Light Theme - Completion Screen */
body.theme-light .completion-screen {
    background: linear-gradient(135deg, #f6f8fa 0%, #ffffff 100%);
    color: #24292f;
}

body.theme-light .completion-header h1 {
    color: #1a7f37;
}

body.theme-light .completion-header h2 {
    color: #57606a;
}

body.theme-light .stats-card {
    background: linear-gradient(135deg, #0969da 0%, #8250df 100%);
}

body.theme-light .learning-card {
    background: #ffffff;
    border-color: #d0d7de;
}

body.theme-light .learning-card h3,
body.theme-light .code-card h3,
body.theme-light .result-card h3 {
    color: #24292f;
}

body.theme-light .learning-card li {
    color: #57606a;
}

body.theme-light .code-card {
    background: #f6f8fa;
    border-color: #d0d7de;
}

body.theme-light .code-card pre {
    background: #ffffff;
    color: #24292f;
}

body.theme-light .result-card {
    background: #f6f8fa;
    border-color: #d0d7de;
}

body.theme-light .completion-terminal .terminal-result {
    color: #0969da;
    text-shadow: none;
}

body.theme-light .btn-retry,
body.theme-light .btn-home {
    background: #f6f8fa;
    border-color: #d0d7de;
    color: #24292f;
}

body.theme-light .btn-retry:hover,
body.theme-light .btn-home:hover {
    background: #eaeef2;
}

body.theme-light .btn-next {
    background: linear-gradient(to right, #2da44e, #238636);
}

body.theme-light .btn-next:hover {
    background: linear-gradient(to right, #238636, #1a7f37);
}

body.theme-light .btn-next:disabled {
    background: #f6f8fa;
    color: #8c959f;
    border: 1px solid #d0d7de;
}

/* ============================================
   Responsive Design
   ============================================ */

/* 태블릿 (1024px 이하) */
@media (max-width: 1024px) {
    .header-container {
        flex-wrap: wrap;
        gap: 15px;
    }

    .header-left {
        flex: 0 0 auto;
    }

    .header-left .title {
        font-size: var(--text-lg);
    }

    .header-center {
        flex: 1 1 auto;
        justify-content: flex-start;
        order: 3;
        width: 100%;
    }

    .header-right {
        flex: 0 0 auto;
        margin-left: auto;
    }

    .timer-display-inner {
        padding: var(--spacing-md) var(--spacing-xl);
        gap: var(--spacing-xl);
    }

    .timer-divider {
        height: 32px;
    }

    .header-spacer {
        height: 130px;
    }
}

/* 모바일 (768px 이하) */
@media (max-width: 768px) {
    .sticky-header {
        padding: var(--spacing-md) var(--spacing-lg);
    }

    .header-container {
        flex-wrap: wrap;
        gap: var(--spacing-md);
    }

    .header-left {
        flex: 1 1 auto;
    }

    .header-left .title {
        font-size: var(--text-base);
    }

    .header-center {
        flex: 1 1 100%;
        order: 3;
        justify-content: flex-start;
        gap: var(--spacing-sm);
    }

    .control-group label {
        display: none;
    }

    .select {
        height: 36px;
        padding: 0 var(--spacing-md);
        font-size: var(--text-sm);
    }

    #language-select { width: 120px; }
    #difficulty-select { width: 100px; }
    #chapter-select { width: 80px; }

    .btn {
        height: 36px;
        padding: 0 var(--spacing-md);
        font-size: var(--text-sm);
    }

    .timer-display-inner {
        padding: var(--spacing-sm) var(--spacing-lg);
        gap: var(--spacing-lg);
    }

    .timer, #wpm {
        font-size: var(--text-base);
    }

    .timer-sublabel, .timer-label {
        font-size: 10px;
    }

    .timer-divider {
        height: 24px;
    }

    .header-spacer {
        height: 110px;
    }

    .container {
        padding: var(--spacing-xl);
    }

    .original-text,
    .user-input {
        margin: var(--spacing-lg);
        padding: var(--spacing-xl);
        font-size: var(--text-base);
    }

    .section-label {
        font-size: var(--text-lg);
        padding: var(--spacing-lg);
    }

    .stats-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .completion-buttons {
        flex-direction: column;
    }

    .completion-buttons button {
        width: 100%;
    }

    .completion-header h1 {
        font-size: var(--text-3xl);
    }

    .completion-header h2 {
        font-size: var(--text-base);
    }
}

/* 소형 모바일 (480px 이하) */
@media (max-width: 480px) {
    .sticky-header {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .header-left .title {
        font-size: var(--text-sm);
    }

    .header-center {
        gap: var(--spacing-xs);
    }

    .select {
        height: 32px;
        padding: 0 var(--spacing-sm);
        font-size: var(--text-xs);
    }

    #language-select { width: 100px; }
    #difficulty-select { width: 80px; }
    #chapter-select { width: 60px; }

    .btn {
        height: 32px;
        padding: 0 var(--spacing-sm);
        font-size: var(--text-xs);
    }

    .timer-display-inner {
        padding: var(--spacing-xs) var(--spacing-md);
        gap: var(--spacing-md);
    }

    .timer, #wpm {
        font-size: var(--text-sm);
    }

    .header-spacer {
        height: 100px;
    }

    .container {
        padding: var(--spacing-lg);
    }

    .original-text,
    .user-input {
        margin: var(--spacing-md);
        padding: var(--spacing-lg);
        font-size: var(--text-sm);
    }

    .section-label {
        font-size: var(--text-base);
        padding: var(--spacing-md);
    }

    .completion-header h1 {
        font-size: var(--text-3xl);
    }

    .stat-value {
        font-size: var(--text-3xl);
    }

    .code-card pre,
    .completion-terminal {
        font-size: var(--text-xs);
    }

    .learning-card,
    .code-card,
    .result-card,
    .stats-card {
        padding: var(--spacing-lg);
    }
}

/* ============================================
   Completion Message (Legacy - hidden)
   ============================================ */

.completion-message {
    display: none;
}