/* ═══════════════════════════════════════════════════════
   2D Basis Explorer – Dark Glassmorphism Theme
   ═══════════════════════════════════════════════════════ */

:root {
    --bg-deep: #0b0e17;
    --bg-card: rgba(17, 21, 35, 0.85);
    --bg-card-hover: rgba(25, 30, 50, 0.92);
    --border: rgba(100, 120, 200, 0.12);
    --border-accent: rgba(108, 140, 255, 0.35);
    --text-primary: #e8ecf4;
    --text-secondary: #8a94a8;
    --text-muted: #5a6378;
    --accent: #6c8cff;
    --accent-glow: rgba(108, 140, 255, 0.25);
    --accent2: #a78bfa;
    --positive: #4ade80;
    --warning: #fbbf24;
    --negative: #ff6b8a;
    --radius: 12px;
    --radius-sm: 8px;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.35);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

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

html {
    font-size: 15px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-deep);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.5;
}

/* ─── Navigation ─── */
#top-nav {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.5rem;
    background: rgba(11, 14, 23, 0.92);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
}

#back-btn {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    background: none;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 0.4rem 0.75rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.85rem;
    transition: all 0.2s;
}

#back-btn:hover {
    color: var(--text-primary);
    border-color: var(--border-accent);
    background: var(--accent-glow);
}

#nav-title {
    font-size: 1.1rem;
    font-weight: 600;
    background: linear-gradient(135deg, var(--accent), var(--accent2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

#image-selector {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

#image-selector label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    white-space: nowrap;
}

#image-selector select {
    min-width: 160px;
}

/* ─── Pages ─── */
.page {
    display: none;
    padding: 1.5rem;
    max-width: 1400px;
    margin: 0 auto;
    animation: fadeIn 0.35s ease;
}

.page.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

.page-header {
    text-align: center;
    margin-bottom: 1.5rem;
}

.page-header h2 {
    font-size: 1.6rem;
    font-weight: 700;
    margin-bottom: 0.3rem;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ─── Cards ─── */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem;
    box-shadow: var(--shadow);
    backdrop-filter: blur(8px);
}

.card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.tag {
    font-size: 0.7rem;
    font-weight: 500;
    background: var(--accent-glow);
    color: var(--accent);
    padding: 0.15rem 0.5rem;
    border-radius: 999px;
    border: 1px solid rgba(108, 140, 255, 0.2);
}

/* ─── Top Row ─── */
#top-row {
    display: grid;
    grid-template-columns: auto auto 1fr;
    gap: 1.25rem;
    margin-bottom: 1.25rem;
    align-items: start;
}

#source-card {
    width: fit-content;
}

#image-canvas-wrap {
    position: relative;
    width: 256px;
    height: 256px;
    border-radius: var(--radius-sm);
    overflow: hidden;
    border: 1px solid var(--border);
}

#image-canvas-wrap canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    cursor: crosshair;
}

#block-card {
    width: fit-content;
    text-align: center;
}

#canvas-block {
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    image-rendering: pixelated;
}

.block-coords {
    margin-top: 0.5rem;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* ─── Controls Card ─── */
#controls-card {
    min-width: 240px;
}

.control-row {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.control-row label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    white-space: nowrap;
}

select {
    flex: 1;
    background: rgba(20, 25, 45, 0.8);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: 0.85rem;
    cursor: pointer;
    transition: border-color 0.2s;
}

select:hover,
select:focus {
    border-color: var(--border-accent);
    outline: none;
}

#canvas-recon {
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    image-rendering: pixelated;
    width: 200px;
    height: 200px;
}

#canvas-coeffs {
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    width: 200px;
    height: 200px;
}

/* ─── Stats ─── */
.stat-row {
    display: flex;
    gap: 0.75rem;
    margin-top: 0.75rem;
    flex-wrap: wrap;
}

.stat-chip {
    display: flex;
    flex-direction: column;
    padding: 0.5rem 0.75rem;
    background: rgba(15, 18, 30, 0.6);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    min-width: 90px;
}

.stat-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 500;
}

.stat-value {
    font-family: var(--font-mono);
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--accent);
}

/* ─── Basis Grid ─── */
#basis-card {
    margin-bottom: 1.25rem;
}

.basis-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.basis-header h3 {
    margin-bottom: 0;
}

.basis-actions {
    display: flex;
    gap: 0.5rem;
}

.btn {
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 500;
    padding: 0.4rem 0.9rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-accent);
    background: var(--accent-glow);
    color: var(--accent);
    cursor: pointer;
    transition: all 0.2s;
}

.btn:hover {
    background: rgba(108, 140, 255, 0.35);
}

.btn-sm {
    font-size: 0.75rem;
    padding: 0.3rem 0.6rem;
}

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

.btn-secondary:hover {
    border-color: var(--negative);
    color: var(--negative);
    background: rgba(255, 107, 138, 0.1);
}

#basis-grid {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    gap: 4px;
}

.basis-cell {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: rgba(15, 18, 30, 0.5);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 4px;
    transition: all 0.2s;
    position: relative;
}

.basis-cell.deselected {
    opacity: 0.35;
    border-color: transparent;
}

.basis-cell canvas {
    width: 100%;
    aspect-ratio: 1;
    border-radius: 4px;
    image-rendering: pixelated;
    cursor: pointer;
}

.basis-cell .coeff-label {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    color: var(--text-secondary);
    margin-top: 2px;
    text-align: center;
    line-height: 1.2;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    width: 100%;
}

.basis-cell .basis-cb {
    position: absolute;
    top: 2px;
    right: 2px;
    width: 14px;
    height: 14px;
    accent-color: var(--accent);
    cursor: pointer;
    z-index: 2;
}

/* ─── Full Image Reconstruction ─── */
#full-stats-card {
    margin-bottom: 2rem;
}

#full-recon-panels {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
}

.full-recon-item {
    text-align: center;
}

.full-recon-label {
    display: block;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.4rem;
}

.full-recon-item canvas {
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    width: 256px;
    height: 256px;
    image-rendering: pixelated;
}

/* ─── Responsive ─── */
@media (max-width: 1100px) {
    #top-row {
        grid-template-columns: 1fr 1fr;
    }

    #controls-card {
        grid-column: 1 / -1;
    }
}

@media (max-width: 750px) {
    #top-row {
        grid-template-columns: 1fr;
    }

    #source-card,
    #block-card {
        width: 100%;
    }

    #image-canvas-wrap {
        width: 100%;
        height: auto;
        aspect-ratio: 1;
    }

    #basis-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (max-width: 480px) {
    .page {
        padding: 1rem 0.75rem;
    }

    #basis-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: 3px;
    }

    .basis-cell .coeff-label {
        font-size: 0.5rem;
    }
}