:root {
    --bg-main: #f4f5f7;
    --bg-card: #ffffff;
    --bg-card-hover: #f8f9fa;
    --bg-input: #f7f7f7;
    --border-color: #d9dde3;
    --border-highlight: #b8bec7;

    --accent-blue: #2563eb;
    --accent-green: #16a34a;
    --accent-red: #dc2626;
    --accent-gold: #b7791f;

    --text-main: #1f2937;
    --text-sub: #6b7280;
    --text-muted: #9ca3af;

    --radius-lg: 12px;
    --radius-md: 9px;
    --radius-sm: 6px;

    --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.08);
    --transition: all 0.15s ease;
}

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

body {
    font-family: 'Space Grotesk', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    min-height: 100vh;
    line-height: 1.5;
    overflow-x: hidden;
}

.app-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    min-height: 100vh;
}

/* Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
}

.brand {
    display: flex;
    align-items: center;
    gap: 16px;
}

.brand-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-md);
    background: var(--bg-card);
    border: 1px solid var(--accent-blue);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-blue);
}

h1 {
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text-main);
}

.subtitle {
    font-size: 0.85rem;
    color: var(--text-sub);
}

.header-badges {
    display: flex;
    gap: 12px;
}

.badge {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    padding: 6px 14px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
}

.badge-label {
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
}

.badge-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-blue);
}

.badge-accent .badge-value {
    color: var(--accent-green);
}

/* Main Grid Layout */
.app-main {
    display: grid;
    grid-template-columns: 320px 1fr;
    gap: 24px;
    align-items: start;
}

.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 20px;
    box-shadow: var(--shadow-card);
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-color);
}

.card-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-main);
    letter-spacing: -0.01em;
}

.grid-spec {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Left Panel: Drawing Canvas */
.panel-drawing {
    position: sticky;
    top: 24px;
}

.canvas-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    background: var(--bg-input);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    padding: 12px;
    transition: var(--transition);
}

.canvas-wrapper:hover {
    border-color: var(--border-highlight);
}

#drawing-canvas {
    width: 280px;
    height: 280px;
    border-radius: var(--radius-sm);
    cursor: crosshair;
    touch-action: none;
    image-rendering: pixelated;
    background: #ffffff;
}

.canvas-controls {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.brush-control {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.control-label {
    font-size: 0.8rem;
    color: var(--text-sub);
    display: flex;
    justify-content: space-between;
}

#brush-size-val {
    font-family: 'JetBrains Mono', monospace;
    color: var(--accent-blue);
    font-weight: 600;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    background: #e5e7eb;
    border-radius: 3px;
    outline: none;
    border: 1px solid var(--border-color);
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent-blue);
    border: 1px solid var(--accent-blue);
    cursor: pointer;
    transition: var(--transition);
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.05);
}

.btn {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 0.85rem;
    font-weight: 600;
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    background: var(--bg-input);
    color: var(--text-main);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: var(--transition);
}

.btn-secondary:hover {
    background: #eeeeee;
    border-color: var(--border-highlight);
    color: var(--text-main);
}

/* Right Panel Layout */
.panel-analysis {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

/* Prediction Cards Grid */
.spotlight {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--bg-input);
    padding: 4px 12px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
}

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

.spotlight-digit {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-blue);
}

.spotlight-conf {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    color: var(--accent-green);
}

.output-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 10px;
}

.output-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 12px 8px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.output-card.winner {
    border-color: var(--accent-blue);
    background: #eff6ff;
}

.digit-number {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-sub);
    transition: var(--transition);
}

.output-card.winner .digit-number {
    color: var(--accent-blue);
}

.confidence-track {
    width: 100%;
    height: 6px;
    background: #e5e7eb;
    border-radius: 3px;
    margin: 8px 0 6px;
    overflow: hidden;
}

.confidence-fill {
    height: 100%;
    width: 0%;
    background: var(--text-muted);
    border-radius: 3px;
    transition: width 0.15s ease-out, background-color 0.2s;
}

.output-card.winner .confidence-fill {
    background: var(--accent-blue);
}

.confidence-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.output-card.winner .confidence-value {
    color: var(--accent-blue);
    font-weight: 600;
}

/* Visualization Panel */
.viz-legend {
    display: flex;
    gap: 12px;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 5px;
}

.legend-color {
    width: 8px;
    height: 8px;
    border-radius: 50%;
}

.legend-color.pos {
    background: var(--accent-blue);
}

.legend-color.neg {
    background: var(--accent-red);
}

.viz-wrapper {
    width: 100%;
    height: 280px;
    background: var(--bg-input);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

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

/* Footer */
.app-footer {
    text-align: center;
    padding: 16px;
    font-size: 0.8rem;
    color: var(--text-muted);
    border-top: 1px solid var(--border-color);
}

/* Responsive Breakpoints */
@media (max-width: 960px) {
    .app-main {
        grid-template-columns: 1fr;
    }

    .panel-drawing {
        position: static;
    }

    .output-grid {
        grid-template-columns: repeat(5, 1fr);
    }
}

@media (max-width: 640px) {
    .app-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }

    .header-badges {
        width: 100%;
        justify-content: space-between;
    }

    .output-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}