/* ============ Reset & Base ============ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-primary: #001633;
    --bg-secondary: #0A2540;
    --bg-card: #0E2A47;
    --text-primary: #FFFFFF;
    --text-secondary: #78909C;
    --accent: #FFAB40;
    --accent-glow: rgba(255, 171, 64, 0.25);
    --accent2: #85D5E6;
    --success: #0097A7;
    --border: #1A3A5C;
    --bar-bg: #0E2A47;
}

body {
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: Arial, 'Segoe UI', system-ui, -apple-system, sans-serif;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ============ Header ============ */
.back-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s;
}

.back-link:hover {
    color: var(--accent);
}

header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 32px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    gap: 16px;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.header-logo {
    width: 32px;
    height: 32px;
    object-fit: contain;
}

header h1 {
    font-size: 1.3rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.mode-switch {
    display: flex;
    align-items: center;
    gap: 12px;
}

.mode-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: color 0.3s;
    font-weight: 500;
}

.mode-label.active {
    color: var(--accent);
    font-weight: 700;
}

/* Toggle switch */
.switch {
    position: relative;
    display: inline-block;
    width: 52px;
    height: 28px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    inset: 0;
    background-color: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: 28px;
    transition: 0.3s;
}

.slider::before {
    content: "";
    position: absolute;
    height: 20px;
    width: 20px;
    left: 2px;
    bottom: 2px;
    background-color: var(--accent);
    border-radius: 50%;
    transition: 0.3s;
}

.switch input:checked + .slider::before {
    transform: translateX(24px);
}

/* ============ Main Layout ============ */
main {
    display: grid;
    grid-template-columns: 300px 1fr 280px;
    gap: 20px;
    padding: 20px 24px;
    height: calc(100vh - 61px);
    min-height: 600px;
}

.panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 20px;
    overflow: hidden;
}

.panel h2 {
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.panel h3 {
    font-size: 0.8rem;
    font-weight: 600;
    margin: 16px 0 10px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* ============ Input Panel ============ */
.input-panel {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.canvas-wrapper {
    border: 2px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
    width: 262px;
    height: 262px;
    background: #000;
}

#draw-canvas {
    display: block;
    width: 260px;
    height: 260px;
    cursor: crosshair;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
}

.btn-group {
    display: flex;
    gap: 8px;
    margin-top: 16px;
    width: 100%;
}

.btn-group button {
    flex: 1;
    padding: 10px 8px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 0.82rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-group button:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--bg-primary);
    box-shadow: 0 0 12px var(--accent-glow);
}

#btn-predict {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--bg-primary);
    font-weight: 700;
}

#btn-predict:hover {
    filter: brightness(1.15);
    box-shadow: 0 0 16px var(--accent-glow);
}

.info-label {
    margin-top: 12px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    min-height: 1.2em;
}

/* ============ Visualization Panel ============ */
.viz-panel {
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

#viz-container {
    flex: 1;
    overflow: auto;
    display: flex;
    align-items: center;
    justify-content: center;
}

#network-svg {
    width: 100%;
    height: 100%;
}

/* ============ Output Panel ============ */
.output-panel {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.prediction-number {
    font-size: 5rem;
    font-weight: 800;
    color: var(--accent);
    text-align: center;
    line-height: 1;
    margin: 8px 0;
    text-shadow: 0 0 20px var(--accent-glow);
    min-height: 80px;
}

/* Probability bars */
.prob-chart {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.prob-row {
    display: flex;
    align-items: center;
    gap: 8px;
}

.prob-label {
    width: 18px;
    text-align: right;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    flex-shrink: 0;
}

.prob-bar-bg {
    flex: 1;
    height: 22px;
    background: var(--bar-bg);
    border-radius: 4px;
    overflow: hidden;
    position: relative;
}

.prob-bar {
    height: 100%;
    background: var(--accent);
    border-radius: 4px;
    transition: width 0.5s ease;
    min-width: 0;
}

.prob-bar.top {
    background: var(--success);
    box-shadow: 0 0 8px rgba(0, 151, 167, 0.4);
}

.prob-value {
    width: 42px;
    text-align: right;
    font-size: 0.78rem;
    color: var(--text-secondary);
    flex-shrink: 0;
    font-variant-numeric: tabular-nums;
}

/* ============ SVG styles ============ */
.layer-label {
    fill: var(--text-secondary);
    font-size: 11px;
    font-family: Arial, 'Segoe UI', system-ui, sans-serif;
    text-anchor: middle;
}

.layer-sublabel {
    fill: var(--text-secondary);
    font-size: 9px;
    font-family: Arial, 'Segoe UI', system-ui, sans-serif;
    text-anchor: middle;
    opacity: 0.7;
}

.node {
    stroke: var(--border);
    stroke-width: 1;
}

.connection {
    stroke: var(--accent);
    stroke-width: 0.7;
    opacity: 0.12;
}

.connection.active {
    opacity: 0.8;
    stroke: var(--accent);
}

/* Loading spinner */
.loading {
    display: none;
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

.loading.show {
    display: block;
}

/* ============ Responsive ============ */
@media (max-width: 1100px) {
    main {
        grid-template-columns: 1fr;
        grid-template-rows: auto 1fr auto;
        height: auto;
    }

    .viz-panel {
        min-height: 500px;
    }
}