/* ═══════════════════════════════════════════════════════════
   MNIST Digit Recognizer — Minimal Black & White
   ═══════════════════════════════════════════════════════════ */

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

:root {
    --bg: #0a0a0a;
    --fg: #ffffff;
    --gray-100: #1a1a1a;
    --gray-200: #2a2a2a;
    --gray-400: #666666;
    --gray-500: #888888;
    --gray-600: #aaaaaa;
    --border: #333333;
    --border-dark: #ffffff;
    --transition: 200ms ease;
}

/* ─── Base ─── */
html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: 'Roboto Mono', monospace;
    background: var(--bg);
    color: var(--fg);
    min-height: 100vh;
    overflow-x: hidden;
}

/* ─── Container ─── */
.container {
    max-width: 1060px;
    margin: 0 auto;
    padding: 3rem 2rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ─── Header ─── */
.header {
    text-align: center;
    margin-bottom: 3rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border);
}

.header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    text-transform: uppercase;
}

.header .accent {
    font-weight: 400;
}

.subtitle {
    color: var(--gray-500);
    font-size: 0.8rem;
    font-weight: 400;
    margin-top: 0.5rem;
    letter-spacing: 0.02em;
}

/* ─── Main Grid ─── */
.main-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    flex: 1;
}

/* ─── Section Shared ─── */
.canvas-section,
.prediction-section {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.section-header h2 {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.12em;
}

/* ─── Buttons ─── */
.canvas-controls {
    display: flex;
    gap: 0.5rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.35rem 0.7rem;
    border: 1px solid var(--border);
    border-radius: 0;
    background: var(--bg);
    color: var(--gray-600);
    font-family: 'Roboto Mono', monospace;
    font-size: 0.7rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.btn:hover {
    background: var(--fg);
    color: var(--bg);
    border-color: var(--fg);
}

/* ─── Canvas ─── */
.canvas-wrapper {
    position: relative;
    background: var(--fg);
    border: 1px solid var(--border-dark);
    overflow: hidden;
    aspect-ratio: 1;
    transition: border-color var(--transition);
}

.canvas-wrapper.drawing {
    border-color: var(--gray-400);
}

#draw-canvas {
    display: block;
    width: 100%;
    height: 100%;
    cursor: crosshair;
    touch-action: none;
}

.canvas-hint {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.6rem;
    color: var(--gray-500);
    font-size: 0.75rem;
    pointer-events: none;
    transition: opacity 400ms ease;
    letter-spacing: 0.05em;
}

.canvas-hint.hidden {
    opacity: 0;
}

.canvas-hint svg {
    opacity: 0.4;
}

/* ─── Brush Control ─── */
.brush-control {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.5rem 0;
    border-top: 1px solid var(--border);
}

.brush-control label {
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    white-space: nowrap;
}

.brush-control input[type="range"] {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    height: 1px;
    background: var(--fg);
    border-radius: 0;
    outline: none;
}

.brush-control input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 12px;
    height: 12px;
    background: var(--fg);
    border-radius: 0;
    cursor: pointer;
    transition: transform var(--transition);
}

.brush-control input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.3);
}

.brush-control input[type="range"]::-moz-range-thumb {
    width: 12px;
    height: 12px;
    background: var(--fg);
    border: none;
    border-radius: 0;
    cursor: pointer;
}

.brush-size-value {
    font-size: 0.7rem;
    color: var(--gray-500);
    min-width: 2.5rem;
    text-align: right;
}

/* ─── Prediction Card ─── */
.prediction-card {
    border: 1px solid var(--border);
    padding: 2rem;
    text-align: center;
    transition: border-color var(--transition);
}

.prediction-card.active {
    border-color: var(--fg);
}

.prediction-label {
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--gray-500);
    margin-bottom: 0.75rem;
}

.prediction-digit {
    font-size: 5rem;
    font-weight: 700;
    line-height: 1;
    color: var(--fg);
    margin-bottom: 0.75rem;
    transition: transform 200ms ease;
}

.prediction-digit.bounce {
    animation: digit-bounce 250ms ease;
}

@keyframes digit-bounce {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

.prediction-confidence {
    font-size: 0.75rem;
    color: var(--gray-500);
    font-weight: 400;
}

.prediction-confidence .confidence-value {
    color: var(--fg);
    font-weight: 600;
}

/* ─── Probability Bars ─── */
.probability-container {
    flex: 1;
    border: 1px solid var(--border);
    padding: 1.25rem;
}

.probability-container h2 {
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--gray-500);
    margin-bottom: 1rem;
}

.probability-bars {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.prob-row {
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

.prob-digit {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--gray-400);
    width: 1.2rem;
    text-align: center;
    transition: color var(--transition);
}

.prob-digit.highlight {
    color: var(--fg);
    font-weight: 700;
}

.prob-bar-track {
    flex: 1;
    height: 18px;
    background: var(--gray-100);
    border: 1px solid var(--gray-200);
    overflow: hidden;
    position: relative;
}

.prob-bar-fill {
    height: 100%;
    width: 0%;
    background: var(--fg);
    transition: width 350ms cubic-bezier(0.4, 0, 0.2, 1);
}


.prob-value {
    font-size: 0.7rem;
    font-weight: 400;
    color: var(--gray-400);
    min-width: 2.8rem;
    text-align: right;
    transition: color var(--transition);
}

.prob-value.highlight {
    color: var(--fg);
    font-weight: 700;
}

/* ─── Footer ─── */
.footer {
    text-align: center;
    padding: 3rem 0 0.5rem;
    color: var(--gray-400);
    font-size: 0.7rem;
    border-top: 1px solid var(--border);
    margin-top: 3rem;
    letter-spacing: 0.03em;
}

/* ─── Responsive ─── */
@media (max-width: 768px) {
    .container {
        padding: 2rem 1.25rem;
    }

    .header h1 {
        font-size: 1.25rem;
    }

    .main-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .prediction-digit {
        font-size: 4rem;
    }

    .canvas-wrapper {
        max-width: 400px;
        margin: 0 auto;
        width: 100%;
    }
}

@media (max-width: 480px) {
    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .prediction-card {
        padding: 1.25rem;
    }

    .prediction-digit {
        font-size: 3rem;
    }
}