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

:root {
    --color-bg: #f5f7fa;
    --color-surface: #ffffff;
    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-secondary: #64748b;
    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-border: #e2e8f0;
    --color-success: #10b981;
    --color-error: #ef4444;
    --color-loading: #f59e0b;
    --radius: 10px;
    --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ─── Header ──────────────────────────────────────────────── */
.tool-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 24px;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo-link {
    display: flex;
    align-items: center;
    text-decoration: none;
}

.logo-img {
    height: 36px;
    width: auto;
}

nav {
    display: flex;
    gap: 24px;
}

nav a {
    color: var(--color-text-light);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    padding: 4px 0;
    border-bottom: 2px solid transparent;
    transition: color 0.2s, border-color 0.2s;
}

nav a:hover,
nav a.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.lang-switch {
    border: 1px solid var(--color-border) !important;
    border-radius: 4px !important;
    padding: 2px 8px !important;
    font-size: 12px !important;
    font-weight: 600 !important;
    letter-spacing: 0.5px;
    line-height: 1.4;
}

.lang-switch:hover {
    background: var(--color-primary) !important;
    color: #fff !important;
    border-color: var(--color-primary) !important;
}

/* ─── Main Layout ─────────────────────────────────────────── */
.tool-main {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* ─── Control Panel ───────────────────────────────────────── */
.control-panel {
    width: 320px;
    min-width: 320px;
    padding: 24px;
    background: var(--color-surface);
    border-right: 1px solid var(--color-border);
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.control-panel h2 {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-text);
}

.control-panel .desc {
    font-size: 13px;
    color: var(--color-text-light);
    line-height: 1.5;
}

.param-group {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.param-group label {
    font-size: 13px;
    font-weight: 600;
    color: var(--color-text-light);
}

.param-group input[type="number"] {
    padding: 8px 12px;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    font-size: 14px;
    outline: none;
    transition: border-color 0.2s;
}

.param-group input[type="number"]:focus {
    border-color: var(--color-primary);
}

.param-group input[type="range"] {
    width: 100%;
    accent-color: var(--color-primary);
}

.param-group span {
    font-size: 13px;
    font-weight: 600;
    color: var(--color-primary);
    text-align: right;
}

/* ─── Buttons ─────────────────────────────────────────────── */
.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

.btn:active {
    transform: scale(0.97);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-primary {
    background: var(--color-primary);
    color: #fff;
}

.btn-primary:hover:not(:disabled) {
    background: var(--color-primary-hover);
}

.btn-secondary {
    background: var(--color-bg);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--color-border);
}

/* ─── Status Bar ──────────────────────────────────────────── */
.status-bar {
    padding: 8px 12px;
    border-radius: 6px;
    font-size: 12px;
    font-weight: 500;
    background: var(--color-bg);
    color: var(--color-text-light);
    text-align: center;
}

.status-bar.success {
    background: #ecfdf5;
    color: #065f46;
}

.status-bar.error {
    background: #fef2f2;
    color: #991b1b;
}

.status-bar.loading {
    background: #fffbeb;
    color: #92400e;
}

/* ─── Stats Panel ─────────────────────────────────────────── */
.stats-panel {
    background: var(--color-bg);
    border-radius: var(--radius);
    padding: 16px;
}

.stats-panel.hidden {
    display: none;
}

.stats-panel h3 {
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--color-text);
}

.stats-panel table {
    width: 100%;
    font-size: 13px;
}

.stats-panel td {
    padding: 4px 0;
}

.stats-panel td:first-child {
    color: var(--color-text-light);
}

.stats-panel td:last-child {
    text-align: right;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

/* ─── Viewer Panel ────────────────────────────────────────── */
.viewer-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    position: relative;
}

#viewer-container {
    flex: 1;
    width: 100%;
}

#viewer-container canvas {
    display: block;
    width: 100% !important;
    height: 100% !important;
}

.viewer-hint {
    position: absolute;
    bottom: 16px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 12px;
    color: var(--color-text-light);
    background: rgba(255,255,255,0.8);
    padding: 4px 12px;
    border-radius: 20px;
    pointer-events: none;
}

/* ─── Responsive ──────────────────────────────────────────── */
@media (max-width: 768px) {
    .tool-main {
        flex-direction: column;
    }
    .control-panel {
        width: 100%;
        min-width: unset;
        border-right: none;
        border-bottom: 1px solid var(--color-border);
    }
    .viewer-panel {
        min-height: 400px;
    }
}

/* ─── Method Selector ───────────────────────────────────────── */
.method-desc {
    font-size: 12px;
    color: var(--color-text-light);
    line-height: 1.5;
    padding: 6px 10px;
    background: #f0f7ff;
    border-left: 3px solid var(--color-primary);
    border-radius: 0 6px 6px 0;
}

.param-group select {
    padding: 8px 12px;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    font-size: 14px;
    outline: none;
    background: var(--color-surface);
    color: var(--color-text);
    cursor: pointer;
    transition: border-color 0.2s;
    appearance: auto;
}

.param-group select:focus {
    border-color: var(--color-primary);
}

.method-params.hidden {
    display: none;
}

/* ─── Layer Stats ─────────────────────────────────────────────── */
.layer-stats {
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--color-border);
}

.layer-stats.hidden {
    display: none;
}

.layer-stats h4 {
    font-size: 13px;
    font-weight: 700;
    margin-bottom: 6px;
    color: var(--color-text);
}

.layer-stats table {
    width: 100%;
    font-size: 12px;
}

.layer-stats td {
    padding: 3px 0;
}

.layer-stats td:first-child {
    color: var(--color-text-light);
    font-size: 11px;
}

.layer-stats td:last-child {
    text-align: right;
    font-weight: 600;
}

/* ─── Fuller Legend ───────────────────────────────────────────── */
.fuller-legend {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 12px;
    background: var(--color-bg);
    border-radius: var(--radius);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    color: var(--color-text-light);
}

.legend-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    flex-shrink: 0;
}