@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800&family=Inter:wght@300;400;500;600;700&display=swap');

:root {
    /* Color Palette */
    --primary-hue: 220;
    --primary: hsl(var(--primary-hue), 90%, 56%);
    --primary-light: hsl(var(--primary-hue), 95%, 65%);
    --primary-glow: hsla(var(--primary-hue), 90%, 56%, 0.15);
    
    --success: hsl(145, 80%, 45%);
    --success-light: hsl(145, 90%, 55%);
    --success-glow: hsla(145, 80%, 45%, 0.15);
    
    --error: hsl(355, 85%, 55%);
    --error-light: hsl(355, 95%, 65%);
    --error-glow: hsla(355, 85%, 55%, 0.15);
    
    --warning: hsl(38, 95%, 50%);
    
    /* Dark Theme Variables (Default) */
    --bg: #0b0f19;
    --card-bg: rgba(17, 24, 39, 0.7);
    --border-color: rgba(255, 255, 255, 0.08);
    --text-main: #f3f4f6;
    --text-muted: #9ca3af;
    --input-bg: rgba(31, 41, 55, 0.5);
    --shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5), 
              0 1px 3px rgba(255, 255, 255, 0.05) inset;
    --glass-blur: blur(12px);
    
    /* Font Families */
    --font-heading: 'Outfit', 'Inter', sans-serif;
    --font-body: 'Inter', sans-serif;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Light Theme Variables */
[data-theme="light"] {
    --bg: #f3f4f6;
    --card-bg: rgba(255, 255, 255, 0.85);
    --border-color: rgba(0, 0, 0, 0.08);
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --input-bg: rgba(255, 255, 255, 0.9);
    --shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.08), 
              0 1px 3px rgba(255, 255, 255, 0.8) inset;
}

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

body {
    background-color: var(--bg);
    color: var(--text-main);
    font-family: var(--font-body);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
    overflow-x: hidden;
    transition: background-color var(--transition-normal), color var(--transition-normal);
    background-image: 
        radial-gradient(at 0% 0%, hsla(220, 90%, 56%, 0.12) 0px, transparent 50%),
        radial-gradient(at 100% 100%, hsla(280, 80%, 50%, 0.08) 0px, transparent 50%);
    background-attachment: fixed;
}

/* Container & Layout */
.app-container {
    width: 100%;
    max-width: 800px;
    z-index: 10;
}

/* Header & Navigation */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.logo {
    font-family: var(--font-heading);
    font-weight: 800;
    font-size: 1.5rem;
    background: linear-gradient(135deg, var(--primary-light), #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.5px;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* Theme Toggle */
.theme-toggle-btn {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    width: 42px;
    height: 42px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow);
}

.theme-toggle-btn:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

/* Cards & Glassmorphism */
.glass-card {
    background: var(--card-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    padding: 2.5rem;
    box-shadow: var(--shadow);
    transition: transform var(--transition-normal), opacity var(--transition-normal);
    position: relative;
    overflow: hidden;
}

/* Screens */
.screen {
    display: none;
    animation: fadeIn var(--transition-normal) forwards;
}

.screen.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Welcome Screen */
.welcome-header {
    text-align: center;
    margin-bottom: 2.5rem;
}

.welcome-badge {
    background: var(--primary-glow);
    color: var(--primary-light);
    border: 1px solid rgba(59, 130, 246, 0.2);
    padding: 0.5rem 1rem;
    border-radius: 9999px;
    font-size: 0.85rem;
    font-weight: 600;
    display: inline-block;
    margin-bottom: 1rem;
    letter-spacing: 0.5px;
    font-family: var(--font-heading);
}

.welcome-title {
    font-family: var(--font-heading);
    font-size: 2.2rem;
    font-weight: 800;
    line-height: 1.25;
    margin-bottom: 1rem;
    letter-spacing: -0.5px;
}

.welcome-desc {
    color: var(--text-muted);
    font-size: 1.05rem;
    line-height: 1.6;
    max-width: 600px;
    margin: 0 auto;
}

/* Mode Selection */
.mode-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 2.5rem;
}

@media (max-width: 600px) {
    .mode-grid {
        grid-template-columns: 1fr;
    }
}

.mode-card {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 2rem;
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    text-align: left;
}

.mode-card:hover {
    border-color: var(--primary);
    transform: translateY(-5px);
    box-shadow: 0 10px 25px -5px var(--primary-glow);
}

.mode-card.selected {
    border-color: var(--primary);
    background: var(--primary-glow);
}

.mode-icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.mode-name {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.25rem;
}

.mode-desc {
    color: var(--text-muted);
    font-size: 0.9rem;
    line-height: 1.5;
}

/* Options / Configuration */
.config-section {
    background: rgba(0, 0, 0, 0.15);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 2.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.config-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.config-label {
    font-weight: 500;
    font-size: 0.95rem;
}

.config-select {
    background: var(--input-bg);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    padding: 0.6rem 1.2rem;
    border-radius: 12px;
    font-family: var(--font-body);
    font-size: 0.9rem;
    cursor: pointer;
    outline: none;
    transition: border-color var(--transition-fast);
}

.config-select:focus {
    border-color: var(--primary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    background: var(--primary);
    color: #fff;
    border: none;
    padding: 1rem 2rem;
    border-radius: 14px;
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.05rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    width: 100%;
    box-shadow: 0 4px 14px 0 var(--primary-glow);
}

.btn:hover {
    background: var(--primary-light);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px 0 var(--primary-glow);
}

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

/* Quiz Screen Top Bar */
.quiz-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    gap: 1rem;
}

.badge-info {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 10px;
    font-size: 0.85rem;
    font-weight: 600;
}

.timer {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--warning);
    font-family: var(--font-heading);
    font-weight: 700;
}

/* Progress bar container */
.progress-container {
    width: 100%;
    height: 6px;
    background: var(--border-color);
    border-radius: 9999px;
    margin-bottom: 2rem;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--primary-light));
    width: 0%;
    transition: width var(--transition-normal);
}

/* Question Area */
.question-box {
    margin-bottom: 2rem;
}

.question-text {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.35rem;
    line-height: 1.45;
    margin-bottom: 1.5rem;
}

/* Options List */
.options-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.option-btn {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 1.1rem 1.5rem;
    text-align: left;
    font-family: var(--font-body);
    font-size: 1rem;
    color: var(--text-main);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 1rem;
    width: 100%;
}

.option-btn:hover:not(.disabled) {
    border-color: var(--primary);
    background: rgba(59, 130, 246, 0.05);
    transform: translateX(4px);
}

.option-letter {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    background: var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 0.95rem;
    transition: background var(--transition-fast);
}

.option-btn:hover:not(.disabled) .option-letter {
    background: var(--primary);
    color: white;
}

/* Question Feedback States */
.option-btn.correct {
    border-color: var(--success);
    background: var(--success-glow);
}

.option-btn.correct .option-letter {
    background: var(--success);
    color: white;
}

.option-btn.incorrect {
    border-color: var(--error);
    background: var(--error-glow);
}

.option-btn.incorrect .option-letter {
    background: var(--error);
    color: white;
}

.option-btn.disabled {
    cursor: not-allowed;
    opacity: 0.6;
}

/* Explanation Accordion */
.explanation-box {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow);
    background: rgba(0, 0, 0, 0.15);
    border-radius: 16px;
}

.explanation-box.active {
    max-height: 400px;
    margin-bottom: 2rem;
    border: 1px solid var(--border-color);
}

.explanation-content {
    padding: 1.5rem;
}

.explanation-title {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.05rem;
    color: var(--success-light);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.explanation-text {
    font-size: 0.92rem;
    line-height: 1.6;
    color: var(--text-muted);
}

/* Quiz Actions Footer */
.quiz-actions {
    display: flex;
    justify-content: flex-end;
}

.quiz-actions .btn {
    width: auto;
    padding: 0.9rem 2.5rem;
}

/* Results Screen Dashboard */
.results-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2.5rem;
}

@media (max-width: 600px) {
    .results-grid {
        grid-template-columns: 1fr;
    }
}

.score-panel {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 2.5rem;
    background: rgba(0, 0, 0, 0.15);
    border-radius: 20px;
    border: 1px solid var(--border-color);
}

.score-circle {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), #a855f7);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
    box-shadow: 0 10px 30px rgba(59, 130, 246, 0.3);
}

.score-num {
    font-family: var(--font-heading);
    font-size: 3.2rem;
    font-weight: 800;
    color: white;
    line-height: 1;
}

.score-total {
    font-size: 0.95rem;
    color: rgba(255, 255, 255, 0.7);
    font-weight: 500;
}

.score-message {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.3rem;
    text-align: center;
    margin-bottom: 0.5rem;
}

.score-submessage {
    color: var(--text-muted);
    font-size: 0.85rem;
    text-align: center;
}

.stats-panel {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 1rem;
}

.stat-item {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 1.2rem;
    display: flex;
    align-items: center;
    gap: 1.2rem;
}

.stat-icon {
    font-size: 1.8rem;
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.05);
    display: flex;
    align-items: center;
    justify-content: center;
}

.stat-info {
    display: flex;
    flex-direction: column;
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.8rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.2rem;
    margin-top: 0.15rem;
}

.results-footer {
    display: flex;
    gap: 1.5rem;
}

@media (max-width: 480px) {
    .results-footer {
        flex-direction: column;
    }
}

.btn-secondary {
    background: var(--input-bg);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    box-shadow: none;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--text-muted);
    box-shadow: none;
}

/* Animations and transitions */
.card-slide-out {
    animation: slideOut var(--transition-normal) forwards;
}

.card-slide-in {
    animation: slideIn var(--transition-normal) forwards;
}

@keyframes slideOut {
    to {
        opacity: 0;
        transform: translateX(-50px);
    }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}