/* CSS Variables for Theming */
:root {
    --primary-color: #4F46E5; /* Indigo 600 */
    --primary-hover: #4338CA; /* Indigo 700 */
    --primary-light: #EEF2FF; /* Indigo 50 */
    
    --secondary-color: #0D9488; /* Teal 600 */
    
    --bg-color: #F8FAFC; /* Slate 50 */
    --card-bg: #FFFFFF;
    --text-main: #1E293B; /* Slate 800 */
    --text-muted: #64748B; /* Slate 500 */
    
    --success-color: #10B981;
    --error-color: #EF4444;
    --warning-color: #F59E0B;

    --border-color: #E2E8F0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);

    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-full: 9999px;

    --font-en: 'Nunito', sans-serif;
    --font-ko: 'Pretendard', sans-serif;
}

/* Dark Mode Theme */
.dark-theme {
    --primary-color: #6366F1;
    --primary-hover: #818CF8;
    --primary-light: #3730A3;
    
    --bg-color: #0F172A; /* Slate 900 */
    --card-bg: #1E293B; /* Slate 800 */
    --text-main: #F1F5F9; /* Slate 100 */
    --text-muted: #94A3B8; /* Slate 400 */
    
    --border-color: #334155;
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

/* High Contrast Mode (Accessibility) */
.high-contrast-theme {
    --primary-color: #000000;
    --primary-hover: #333333;
    --primary-light: #E0E0E0;
    --bg-color: #FFFFFF;
    --card-bg: #FFFFFF;
    --text-main: #000000;
    --text-muted: #222222;
    --border-color: #000000;
}

/* Reset & Base Styles */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-ko);
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
    -webkit-font-smoothing: antialiased;
}

.en-text {
    font-family: var(--font-en);
}

/* Layout */
.app-container {
    max-width: 600px; /* Mobile first, tablet size max */
    margin: 0 auto;
    min-height: 100vh;
    background-color: var(--bg-color);
    position: relative;
    overflow-x: hidden;
    box-shadow: var(--shadow-xl);
}

header {
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 10;
}

header h1 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.header-actions button {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--text-muted);
    cursor: pointer;
    padding: 8px;
    border-radius: var(--radius-full);
    transition: background 0.2s;
}

.header-actions button:hover {
    background-color: var(--primary-light);
    color: var(--primary-color);
}

main {
    padding: 20px;
    padding-bottom: 100px;
}

/* Typography & Accessibility */
h1, h2, h3 { color: var(--text-main); }
.text-lg { font-size: 1.125rem; }
.text-xl { font-size: 1.25rem; font-weight: 700; }
.text-2xl { font-size: 1.5rem; font-weight: 700; }
.text-muted { color: var(--text-muted); font-size: 0.9rem; }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    border-radius: var(--radius-lg);
    font-family: var(--font-ko);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    gap: 8px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-primary:active {
    transform: translateY(1px);
}

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

.btn-secondary:hover {
    background-color: #E0E7FF;
}

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-main);
}

.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.btn-play {
    background-color: var(--primary-color);
    color: white;
    width: 64px;
    height: 64px;
    border-radius: var(--radius-full);
    font-size: 2rem;
    box-shadow: 0 4px 14px rgba(79, 70, 229, 0.4);
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn-play:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 20px rgba(79, 70, 229, 0.6);
}

.btn-play:active {
    transform: scale(0.95);
}

/* Cards */
.card {
    background-color: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: 20px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    margin-bottom: 20px;
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

/* Grid Layouts */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}

/* Question Options */
.option-btn {
    width: 100%;
    text-align: left;
    padding: 16px 20px;
    background-color: var(--card-bg);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    margin-bottom: 12px;
    font-size: 1rem;
    color: var(--text-main);
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
}

.option-btn:hover {
    border-color: var(--primary-color);
    background-color: var(--primary-light);
}

.option-btn.selected {
    border-color: var(--primary-color);
    background-color: var(--primary-light);
    font-weight: 600;
}

.option-btn.correct {
    border-color: var(--success-color);
    background-color: #ECFDF5;
    color: #065F46;
}

.option-btn.wrong {
    border-color: var(--error-color);
    background-color: #FEF2F2;
    color: #991B1B;
}

.dark-theme .option-btn.correct {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--success-color);
}

.dark-theme .option-btn.wrong {
    background-color: rgba(239, 68, 68, 0.1);
    color: var(--error-color);
}

/* Player UI */
.player-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    padding: 30px 20px;
    background: linear-gradient(to bottom, var(--primary-light), var(--bg-color));
    border-radius: var(--radius-lg);
    margin-bottom: 24px;
}

.dark-theme .player-container {
    background: linear-gradient(to bottom, var(--card-bg), var(--bg-color));
}

.player-controls {
    display: flex;
    align-items: center;
    gap: 16px;
}

.speed-control {
    display: flex;
    gap: 8px;
    background-color: var(--card-bg);
    padding: 4px;
    border-radius: var(--radius-full);
    border: 1px solid var(--border-color);
}

.speed-btn {
    padding: 6px 12px;
    border: none;
    background: none;
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
}

.speed-btn.active {
    background-color: var(--primary-color);
    color: white;
}

/* Badge */
.badge {
    display: inline-block;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.badge-elem { background-color: #FEF08A; color: #854D0E; }
.badge-mid { background-color: #A7F3D0; color: #065F46; }
.badge-high { background-color: #BFDBFE; color: #1E40AF; }
.dark-theme .badge-elem { background-color: #854D0E; color: #FEF08A; }
.dark-theme .badge-mid { background-color: #065F46; color: #A7F3D0; }
.dark-theme .badge-high { background-color: #1E40AF; color: #BFDBFE; }

/* Progress Bar */
.progress-container {
    width: 100%;
    height: 8px;
    background-color: var(--border-color);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin-bottom: 20px;
}

.progress-bar {
    height: 100%;
    background-color: var(--primary-color);
    width: 0%;
    transition: width 0.3s ease;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-in {
    animation: fadeIn 0.4s ease-out forwards;
}

/* Utility */
.text-center { text-align: center; }
.mt-2 { margin-top: 8px; }
.mt-4 { margin-top: 16px; }
.mb-2 { margin-bottom: 8px; }
.mb-4 { margin-bottom: 16px; }
.flex { display: flex; }
.justify-between { justify-content: space-between; }
.align-center { align-items: center; }
.gap-2 { gap: 8px; }
.gap-4 { gap: 16px; }
.hidden { display: none !important; }

/* Bottom Nav */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 600px;
    background-color: var(--card-bg);
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-around;
    padding: 12px 0 20px 0;
    box-shadow: 0 -4px 6px -1px rgba(0, 0, 0, 0.05);
    z-index: 10;
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    color: var(--text-muted);
    background: none;
    border: none;
    cursor: pointer;
    font-size: 0.75rem;
}

.nav-item.active {
    color: var(--primary-color);
    font-weight: 700;
}

.nav-item svg {
    width: 24px;
    height: 24px;
    fill: currentColor;
}

/* Loader */
.loader {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
}
.spinner {
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
}
@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }

/* Screen Views */
.view {
    display: none;
}
.view.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

/* Settings modal */
.modal-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 50;
    backdrop-filter: blur(4px);
}
.modal {
    background: var(--card-bg);
    width: 90%;
    max-width: 400px;
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-lg);
    max-height: 85vh;
    overflow-y: auto;
}

/* --- PHASE 2 업그레이드 스타일 --- */
.blind-active {
    filter: blur(8px);
    pointer-events: none;
    user-select: none;
    opacity: 0.5;
    transition: filter 0.5s ease, opacity 0.5s ease;
}

.script-line {
    padding: 6px 10px;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s;
    margin-bottom: 4px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.script-line:hover {
    background-color: var(--primary-light);
    color: var(--primary-color);
}

.dark-theme .script-line:hover {
    background-color: rgba(99, 102, 241, 0.15);
}

.script-line::before {
    content: '▶';
    font-size: 0.8rem;
    opacity: 0.5;
}