/* ── Design Tokens ─────────────────────────────────── */
:root {
    --bg:           #0a0e14;
    --bg-card:      #111820;
    --bg-glass:     rgba(17, 24, 32, 0.72);
    --border:       rgba(0,180,216,0.18);
    --border-hover: rgba(0,180,216,0.45);
    --accent:       #00b4d8;
    --accent-glow:  rgba(0,180,216,0.35);
    --accent-dim:   #008da6;
    --text:         #d0d8e0;
    --text-muted:   #6b7a8d;
    --text-bright:  #f0f4f8;
    --radius:       10px;
    --transition:   0.25s ease;
    --font:         'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 16px 20px 40px;
    -webkit-font-smoothing: antialiased;
}

/* ── Back Button ───────────────────────────────────── */
#backBtn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--bg-glass);
    border: 1px solid var(--border);
    color: var(--accent);
    font: 600 0.82rem var(--font);
    padding: 7px 16px;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    backdrop-filter: blur(12px);
}
#backBtn:hover {
    background: rgba(0,180,216,0.12);
    border-color: var(--border-hover);
    box-shadow: 0 0 14px var(--accent-glow);
}

/* ── Header ────────────────────────────────────────── */
#appHeader {
    text-align: center;
    margin: 20px auto 24px;
    max-width: 680px;
}
#appHeader h1 {
    font-size: 1.65rem;
    font-weight: 700;
    color: var(--text-bright);
    letter-spacing: -0.3px;
}
#appHeader .accent { color: var(--accent); }
.subtitle {
    margin-top: 6px;
    font-size: 0.84rem;
    color: var(--text-muted);
    line-height: 1.45;
}

/* ── Controls ──────────────────────────────────────── */
#controls {
    display: flex;
    flex-wrap: wrap;
    gap: 14px 20px;
    justify-content: center;
    max-width: 960px;
    margin: 0 auto 28px;
    padding: 18px 22px;
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    backdrop-filter: blur(14px);
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 5px;
    min-width: 160px;
}
.control-group label {
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.6px;
    color: var(--text-muted);
}

select, input[type="file"] {
    background: var(--bg);
    border: 1px solid var(--border);
    color: var(--text);
    font: 500 0.82rem var(--font);
    padding: 7px 10px;
    border-radius: 6px;
    outline: none;
    transition: var(--transition);
}
select:focus { border-color: var(--accent); box-shadow: 0 0 8px var(--accent-glow); }

/* Range Slider */
input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    background: #1a2230;
    border-radius: 3px;
    outline: none;
    margin-top: 4px;
}
input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px; height: 16px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    box-shadow: 0 0 8px var(--accent-glow);
    transition: var(--transition);
}
input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.25);
    box-shadow: 0 0 14px var(--accent-glow);
}
input[type="range"]::-moz-range-thumb {
    width: 16px; height: 16px;
    border: none;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    box-shadow: 0 0 8px var(--accent-glow);
}

/* Buttons */
.btn-group { justify-content: flex-end; align-self: flex-end; }
#reconstructBtn {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    font: 600 0.84rem var(--font);
    padding: 10px 22px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    color: #fff;
    background: linear-gradient(135deg, var(--accent), var(--accent-dim));
    box-shadow: 0 2px 12px var(--accent-glow);
    transition: var(--transition);
}
#reconstructBtn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 22px var(--accent-glow);
}
#reconstructBtn:active { transform: translateY(0); }
#reconstructBtn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* ── Display Grid ──────────────────────────────────── */
#display {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 24px;
    max-width: 960px;
    margin: 0 auto 24px;
}

.panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px;
    text-align: center;
    position: relative;
    transition: var(--transition);
}
.panel:hover {
    border-color: var(--border-hover);
    box-shadow: 0 0 20px rgba(0,180,216,0.08);
}
.panel h2 {
    font-size: 0.78rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    color: var(--accent);
    margin-bottom: 10px;
}
.panel canvas {
    width: 100%;
    height: auto;
    border-radius: 4px;
    image-rendering: pixelated;
    background: #000;
}

#downloadBtn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin-top: 12px;
    padding: 6px 14px;
    font: 600 0.75rem var(--font);
    color: var(--accent);
    background: rgba(0, 180, 216, 0.1);
    border: 1px solid var(--border);
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition);
}
#downloadBtn:hover {
    background: rgba(0, 180, 216, 0.2);
    border-color: var(--accent);
    box-shadow: 0 0 8px var(--accent-glow);
}
#downloadBtn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Arrows between panels (desktop only) */
.arrow-right::before {
    content: '→';
    position: absolute;
    left: -18px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.3rem;
    color: var(--accent);
    opacity: 0.5;
}

/* ── Metrics ───────────────────────────────────────── */
#metrics {
    display: flex;
    gap: 16px;
    justify-content: center;
    max-width: 960px;
    margin: 0 auto 32px;
}
.metric-card {
    flex: 1;
    max-width: 200px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px 18px;
    text-align: center;
    transition: var(--transition);
}
.metric-card:hover { border-color: var(--border-hover); }
.metric-label {
    display: block;
    font-size: 0.68rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-muted);
    margin-bottom: 4px;
}
.metric-value {
    display: block;
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
}

/* ── Progress Overlay ──────────────────────────────── */
#progressOverlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.65);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(4px);
}
#progressOverlay.hidden { display: none; }
#progressBox {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 36px;
    text-align: center;
    min-width: 280px;
}
#progressBarTrack {
    width: 100%;
    height: 6px;
    background: #1a2230;
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 12px;
}
#progressBarFill {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--accent), #00e5ff);
    border-radius: 3px;
    transition: width 0.15s ease;
}
#progressText {
    font-size: 0.82rem;
    color: var(--text-muted);
}

/* ── Responsive ────────────────────────────────────── */
@media (max-width: 768px) {
    body { padding: 12px 10px 32px; }
    #appHeader h1 { font-size: 1.25rem; }
    #controls { padding: 14px; gap: 12px; }
    .control-group { min-width: 100%; }

    #display {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    .arrow-right::before { display: none; }

    #metrics { flex-direction: column; align-items: center; }
    .metric-card { max-width: 100%; width: 100%; }
}

/* ── Animations ────────────────────────────────────── */
@keyframes borderPulse {
    0%, 100% { border-color: var(--border); }
    50% { border-color: var(--accent); }
}
.panel.computing {
    animation: borderPulse 1.2s ease infinite;
}