/**
 * Let's Go Bounce — DDR Rhythm Game Styles
 */

/* ===== Reset & Variables ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --color-bg-dark: #0a0a1a;
    --color-bg-card: #12122a;
    --color-bg-elevated: #1a1a3a;
    --color-primary: #00d4ff;
    --color-primary-glow: rgba(0, 212, 255, 0.4);
    --color-secondary: #ff6b9d;
    --color-accent: #7c3aed;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-text: #ffffff;
    --color-text-muted: #a0a0c0;
    --color-text-dim: #606080;
    --gradient-primary: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    --gradient-energetic: linear-gradient(135deg, #ff6b9d, #ff8a5c, #ffd93d);
    --gradient-bg: radial-gradient(ellipse at top, #1a1a4a 0%, #0a0a1a 100%);
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --radius-sm: 0.375rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;
    --shadow-glow: 0 0 30px var(--color-primary-glow);
    --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.3);
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

html, body {
    height: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--gradient-bg);
    background-attachment: fixed;
    color: var(--color-text);
    line-height: 1.5;
    overflow: hidden;
}

/* ===== Layout ===== */
.app-container {
    height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-sm) var(--space-lg);
    background: rgba(10, 10, 26, 0.9);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    z-index: 10;
}

.back-link {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

.back-link:hover {
    color: var(--color-primary);
}

.title {
    font-size: 1.125rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.main-content {
    flex: 1;
    display: flex;
    min-height: 0;
    position: relative;
}

/* ===== Screens ===== */
.screen {
    display: none;
    width: 100%;
}

.screen.active {
    display: flex;
}

/* Setup & Summary: centered card */
#setup-screen,
#summary-screen {
    justify-content: center;
    align-items: center;
    padding: var(--space-lg);
    animation: fadeIn var(--transition-normal);
}

/* Game: column layout filling space */
#game-screen {
    flex-direction: column;
}

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

/* ===== Setup Screen ===== */
.setup-card {
    max-width: 460px;
    width: 100%;
    padding: var(--space-2xl);
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: var(--shadow-card);
    text-align: center;
}

.setup-card h2 {
    font-size: 1.75rem;
    margin-bottom: var(--space-sm);
    background: var(--gradient-energetic);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.intro-text {
    color: var(--color-text-muted);
    margin-bottom: var(--space-xl);
}

.setup-steps {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    margin-bottom: var(--space-xl);
    text-align: left;
}

.step {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-sm) var(--space-md);
    background: var(--color-bg-elevated);
    border-radius: var(--radius-md);
}

.step-number {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    font-weight: 700;
    font-size: 0.8rem;
    flex-shrink: 0;
}

.step-text {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

/* ===== Song Select ===== */
.song-select {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    margin-bottom: var(--space-xl);
    text-align: left;
}

.song-option {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-sm) var(--space-md);
    background: var(--color-bg-elevated);
    border-radius: var(--radius-md);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.song-option:hover {
    border-color: rgba(0, 212, 255, 0.3);
}

.song-option.selected {
    border-color: var(--color-primary);
    background: rgba(0, 212, 255, 0.1);
}

.song-info {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.song-title {
    font-weight: 600;
    font-size: 0.9375rem;
}

.song-artist {
    font-size: 0.75rem;
    color: var(--color-text-muted);
}

.song-meta {
    display: flex;
    gap: var(--space-sm);
    align-items: center;
}

.song-bpm, .song-difficulty {
    font-size: 0.75rem;
    padding: 2px 8px;
    border-radius: var(--radius-full);
    font-weight: 600;
}

.song-bpm {
    background: rgba(255, 255, 255, 0.1);
    color: var(--color-text-muted);
}

.song-difficulty {
    color: white;
}

.diff-easy { background: var(--color-success); }
.diff-normal { background: var(--color-primary); }
.diff-hard { background: var(--color-secondary); }
.diff-free { background: var(--color-accent); }

.camera-note {
    margin-top: var(--space-xl);
    font-size: 0.75rem;
    color: var(--color-text-dim);
}

/* ===== Beat Timeline Bar ===== */
.beat-timeline {
    flex-shrink: 0;
    height: 32px;
    background: rgba(10, 10, 26, 0.95);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    position: relative;
    overflow: hidden;
}

.timeline-progress {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    background: rgba(0, 212, 255, 0.1);
    transition: width 100ms linear;
}

.timeline-playhead {
    position: absolute;
    top: 0;
    left: 33%;
    width: 2px;
    height: 100%;
    background: rgba(0, 212, 255, 0.6);
}

/* ===== Buttons ===== */
.primary-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    background: var(--gradient-primary);
    border: none;
    border-radius: var(--radius-full);
    color: white;
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
    box-shadow: var(--shadow-glow);
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 40px var(--color-primary-glow);
}

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

.secondary-btn {
    padding: var(--space-md) var(--space-xl);
    background: transparent;
    border: 2px solid var(--color-text-muted);
    border-radius: var(--radius-full);
    color: var(--color-text-muted);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.secondary-btn:hover {
    border-color: var(--color-text);
    color: var(--color-text);
}

/* ===== Game Screen ===== */
.game-area {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    background: #000;
    overflow: hidden;
    min-height: 0;
}

.video-wrapper {
    position: relative;
    width: 100%;
    max-height: 100%;
    aspect-ratio: 4 / 3;
    overflow: hidden;
}

#webcam {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transform: scaleX(-1);
}

#game-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    transform: scaleX(-1);
    z-index: 1;
}

/* ===== Overlays ===== */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 5;
}

.calibration-overlay {
    background: rgba(10, 10, 26, 0.75);
    backdrop-filter: blur(4px);
}

.overlay-card {
    text-align: center;
    padding: var(--space-2xl);
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    border: 1px solid rgba(255, 255, 255, 0.15);
    box-shadow: var(--shadow-card);
    max-width: 400px;
    width: 90%;
}

.overlay-card h2 {
    font-size: 1.5rem;
    margin-bottom: var(--space-md);
    color: var(--color-primary);
}

.overlay-card p {
    color: var(--color-text-muted);
    margin-bottom: var(--space-lg);
    line-height: 1.6;
}

/* ===== Countdown ===== */
.countdown-overlay {
    background: rgba(10, 10, 26, 0.6);
}

.countdown-number {
    font-size: 8rem;
    font-weight: 800;
    color: var(--color-primary);
    text-shadow: 0 0 60px var(--color-primary-glow), 0 0 120px var(--color-primary-glow);
    animation: countPulse 1s ease-in-out infinite;
}

@keyframes countPulse {
    0%, 100% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.1); opacity: 0.8; }
}

/* ===== Game HUD ===== */
.game-hud {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 3;
}

.hud-top-left {
    position: absolute;
    top: var(--space-md);
    left: var(--space-md);
}

.hud-score {
    font-size: 2rem;
    font-weight: 800;
    color: var(--color-text);
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.8);
    font-variant-numeric: tabular-nums;
}

.hud-top-right {
    position: absolute;
    top: var(--space-md);
    right: var(--space-md);
}

.hud-combo {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--color-warning);
    text-shadow: 0 0 20px rgba(245, 158, 11, 0.6), 0 2px 8px rgba(0, 0, 0, 0.8);
    font-variant-numeric: tabular-nums;
    transition: transform 150ms ease-out;
}

.grade-display {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 3rem;
    font-weight: 800;
    text-shadow: 0 0 30px currentColor, 0 2px 8px rgba(0, 0, 0, 0.8);
    opacity: 0;
    transition: opacity 0.15s ease;
    pointer-events: none;
}

/* ===== Game Controls ===== */
.game-controls {
    flex-shrink: 0;
    display: flex;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    background: rgba(10, 10, 26, 0.9);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    z-index: 10;
}

.control-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-md);
    background: var(--color-bg-elevated);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    color: var(--color-text-muted);
    font-size: 0.8125rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.control-btn.active {
    background: rgba(255, 107, 157, 0.2);
    border-color: var(--color-secondary);
    color: var(--color-secondary);
}

.control-btn.stop {
    margin-left: auto;
    background: rgba(239, 68, 68, 0.15);
    border-color: rgba(239, 68, 68, 0.3);
    color: var(--color-danger);
}

.control-btn.stop:hover {
    background: rgba(239, 68, 68, 0.3);
    border-color: var(--color-danger);
}

/* ===== Summary Screen ===== */
.summary-card {
    max-width: 460px;
    width: 100%;
    padding: var(--space-2xl);
    background: var(--color-bg-card);
    border-radius: var(--radius-xl);
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: var(--shadow-card);
    text-align: center;
}

.summary-header h2 {
    font-size: 1.75rem;
    margin-bottom: var(--space-xs);
    background: var(--gradient-energetic);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.summary-message {
    color: var(--color-text-muted);
    margin-bottom: var(--space-xl);
}

.summary-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
}

.summary-stat {
    padding: var(--space-md);
    background: var(--color-bg-elevated);
    border-radius: var(--radius-md);
}

.summary-value {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--space-xs);
    font-variant-numeric: tabular-nums;
}

.summary-label {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.summary-grades {
    margin-bottom: var(--space-xl);
    text-align: left;
}

.grade-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-sm) var(--space-md);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    font-variant-numeric: tabular-nums;
}

.grade-label {
    font-weight: 600;
    font-size: 0.875rem;
}

.grade-label.perfect { color: #ffd700; }
.grade-label.great { color: var(--color-primary); }
.grade-label.good { color: var(--color-text); }
.grade-label.miss { color: var(--color-danger); }

.summary-actions {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

/* ===== Utilities ===== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}