/* =========================================================================
   Gradient Descent — FunSlop.com
   Self-contained neon reskin of a gravity-slingshot physics puzzle.
   ========================================================================= */

:root {
    --bg-dark: #090b10;
    --bg-deep: #0c0716;
    --neon-green: #39ff14;
    --neon-purple: #bd00ff;
    --accent-cyan: #05d9e8;
    --accent-pink: #ff2a6d;
    --accent-gold: #ffd54a;
    --text-primary: #f0f4f8;
    --text-muted: #8b9bb4;
    --glass-border: rgba(255, 255, 255, 0.08);
    --radius-sm: 8px;
}

* {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    overflow: hidden;
    font-family: 'Outfit', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
}

.game-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    user-select: none;
    -webkit-user-select: none;
    touch-action: none;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    background: linear-gradient(180deg, rgba(12, 7, 22, 0.92) 0%, rgba(9, 11, 16, 0.4) 100%);
    border-bottom: 1px solid var(--glass-border);
}

.title {
    margin: 0;
    font-family: 'Space Grotesk', system-ui, sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--neon-green);
    text-shadow: 0 0 12px rgba(57, 255, 20, 0.5);
    letter-spacing: 0.02em;
}

.stats {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.stat-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.1rem;
}

.stat-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.stat-value {
    font-family: 'Space Grotesk', system-ui, sans-serif;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
}

#strokes {
    color: var(--accent-cyan);
    text-shadow: 0 0 10px rgba(5, 217, 232, 0.4);
}

#par {
    color: var(--neon-green);
    text-shadow: 0 0 10px rgba(57, 255, 20, 0.35);
}

.game-area {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: radial-gradient(ellipse at center, #0c0716 0%, #090b10 100%);
}

#canvas {
    display: block;
    width: 100%;
    height: 100%;
}

.controls-block {
    padding: 0.75rem 1rem 3.5rem;
    text-align: center;
    background: rgba(9, 11, 16, 0.4);
}

.controls-row {
    display: flex;
    justify-content: center;
}

.control-pill {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    padding: 0.35rem 0.9rem;
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    background: rgba(189, 0, 255, 0.06);
}

.control-pill .touch {
    width: 0.7rem;
    height: 0.7rem;
    border-radius: 50%;
    background: var(--accent-cyan);
    box-shadow: 0 0 8px rgba(5, 217, 232, 0.7);
}

.restart-btn {
    margin-top: 0.5rem;
    background: rgba(255, 255, 255, 0.06);
    color: var(--text-muted);
    border: 1px solid var(--glass-border);
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
    font-family: 'Outfit', system-ui, sans-serif;
    font-weight: 500;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: none;
    -webkit-tap-highlight-color: transparent;
}

.restart-btn:hover {
    background: rgba(189, 0, 255, 0.18);
    border-color: var(--neon-purple);
    color: var(--text-primary);
}

.restart-btn:active {
    transform: scale(0.98);
}

.state-playing .restart-btn {
    display: inline-block;
}

/* Overlay */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(9, 7, 16, 0.97);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
    backdrop-filter: blur(6px);
}

.overlay.visible {
    opacity: 1;
    pointer-events: auto;
}

.overlay-content {
    text-align: center;
    padding: 2rem;
    max-width: 420px;
}

.overlay-title {
    font-family: 'Space Grotesk', system-ui, sans-serif;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--neon-green);
    text-shadow: 0 0 20px rgba(57, 255, 20, 0.5);
    margin: 0 0 1rem;
}

.overlay-text {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin: 0 0 1.5rem;
    line-height: 1.5;
}

.overlay-score {
    font-family: 'Space Grotesk', system-ui, sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--neon-green);
    margin: 0 0 0.5rem;
}

.overlay-best {
    font-size: 1rem;
    color: var(--text-muted);
    margin: 0 0 1rem;
}

/* Score result colors */
.overlay-score.under-par { color: var(--neon-green); text-shadow: 0 0 16px rgba(57, 255, 20, 0.5); }
.overlay-score.on-par { color: var(--accent-cyan); text-shadow: 0 0 16px rgba(5, 217, 232, 0.5); }
.overlay-score.over-par { color: var(--accent-pink); text-shadow: 0 0 16px rgba(255, 42, 109, 0.5); }

/* Level Select Grid */
.level-select {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.5rem;
    margin: 1rem auto;
    max-width: 280px;
}

.level-btn {
    width: 48px;
    height: 48px;
    border: 2px solid var(--glass-border);
    background: rgba(255, 255, 255, 0.04);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: 'Space Grotesk', system-ui, sans-serif;
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    -webkit-tap-highlight-color: transparent;
}

.level-btn:hover {
    background: rgba(189, 0, 255, 0.12);
    border-color: var(--neon-purple);
}

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

.level-btn:focus-visible {
    outline: 2px solid rgba(5, 217, 232, 0.6);
    outline-offset: 2px;
}

.level-btn.current {
    border-color: var(--accent-cyan);
    background: rgba(5, 217, 232, 0.18);
    box-shadow: 0 0 12px rgba(5, 217, 232, 0.3);
}

.level-btn.completed {
    border-color: var(--neon-green);
}

.level-btn .score {
    font-size: 0.5rem;
    color: var(--text-muted);
}

.level-btn .score.good {
    color: var(--neon-green);
}

.share-container {
    margin: 1rem 0;
}

.start-btn {
    background: linear-gradient(135deg, var(--neon-green), var(--accent-cyan));
    color: #04110a;
    border: none;
    padding: 1rem 2.5rem;
    font-family: 'Space Grotesk', system-ui, sans-serif;
    font-size: 1.25rem;
    font-weight: 700;
    border-radius: 50px;
    cursor: pointer;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
    -webkit-tap-highlight-color: transparent;
}

.start-btn:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 24px rgba(57, 255, 20, 0.45);
}

.start-btn:active {
    transform: scale(0.98);
}

.start-btn:focus-visible {
    outline: 3px solid rgba(57, 255, 20, 0.5);
    outline-offset: 2px;
}

.home-link {
    position: fixed;
    bottom: 1rem;
    left: 50%;
    transform: translateX(-50%);
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--glass-border);
    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
    z-index: 200;
}

.home-link:hover {
    background: rgba(189, 0, 255, 0.15);
    border-color: var(--neon-purple);
    color: var(--text-primary);
}

/* SEO content - visually hidden but accessible to crawlers */
.seo-content {
    position: absolute;
    left: -9999px;
    width: 1px;
    height: 1px;
    overflow: hidden;
}

/* State-based visibility */
.state-playing .controls-block {
    opacity: 0.4;
}

.state-idle .level-select {
    display: grid;
}

.state-playing .overlay {
    opacity: 0;
    pointer-events: none;
}

/* Convergence celebration */
.overlay-title.hole-complete {
    animation: celebrate 0.5s ease;
}

@keyframes celebrate {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); color: var(--accent-cyan); }
}

/* Responsive */
@media (max-width: 600px) {
    .header {
        padding: 0.75rem 1rem;
    }

    .title {
        font-size: 1.25rem;
    }

    .stats {
        gap: 0.75rem;
    }

    .stat-label {
        font-size: 0.6rem;
    }

    .stat-value {
        font-size: 1rem;
    }

    .overlay-title {
        font-size: 2rem;
    }

    .overlay-text {
        font-size: 1rem;
    }

    .controls-block {
        padding: 0.5rem 1rem 3rem;
    }

    .level-select {
        max-width: 240px;
    }

    .level-btn {
        width: 42px;
        height: 42px;
        font-size: 1rem;
    }
}

@media (max-height: 600px) {
    .header {
        padding: 0.5rem 1rem;
    }

    .overlay-content {
        padding: 1rem;
    }

    .overlay-title {
        font-size: 1.75rem;
        margin-bottom: 0.5rem;
    }
}