:root {
    /* Light Mode */
    --background: #ffffff;
    --primary-text: #1a1a1a;
    --secondary-text: #57606a;
    --card-bg: #f6f8fa;
    --border: #d0d7de;
    --link-accent: #0969da;
    
    /* Price Colors (High Contrast) */
    --price-cheap: #22c55e;
    --price-moderate: #eab308;
    --price-expensive: #f97316;
    --price-very-expensive: #ef4444;
}

[data-theme="dark"] {
    /* Dark Mode (High Contrast) */
    --background: #0d1117;
    --primary-text: #e6edf3;
    --secondary-text: #b0bec5;
    --card-bg: #161b22;
    --border: #30363d;
    --link-accent: #58a6ff;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    background-color: var(--background);
    color: var(--primary-text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    line-height: 1.5;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 1200px; /* Slightly wider for larger charts */
    margin: 0 auto;
    padding: 0 16px;
}

header {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border);
    padding: 12px 0;
    margin-bottom: 24px;
}

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

.logo { font-size: 1.25rem; font-weight: 600; }
.header-controls { display: flex; align-items: center; gap: 12px; }

.theme-btn {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--primary-text);
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1.2rem;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 24px;
    margin-bottom: 24px;
}

.card-header {
    font-size: 0.875rem;
    color: var(--secondary-text);
    margin-bottom: 12px;
    font-weight: 500;
    text-transform: uppercase;
}

.current-price-card { text-align: center; }

.price-value {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 8px;
    color: var(--link-accent);
}

.price-time {
    font-size: 1.1rem;
    color: var(--secondary-text);
}

.heatmap-wrapper {
    overflow-x: auto;
    background: var(--card-bg);
    padding: 15px;
    border: 1px solid var(--border);
    border-radius: 8px;
    margin-top: 10px;
}

.heatmap-grid {
    display: grid;
    gap: 4px;
    min-width: 1100px;
}

.heatmap-header-cell {
    text-align: center;
    font-size: 0.85rem;
    font-weight: bold;
    padding: 10px 0;
    color: var(--primary-text);
    border-bottom: 2px solid var(--border);
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 4px;
}

.reliability-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    font-weight: 800;
    color: var(--secondary-text);
}

.reliability-label .rel-actual { color: #58a6ff !important; }
.reliability-label .rel-high { color: #22c55e !important; }
.reliability-label .rel-med { color: #eab308 !important; }
.reliability-label .rel-low { color: #ef4444 !important; }

.heatmap-row-label {
    font-size: 0.75rem;
    color: var(--secondary-text);
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding-right: 12px;
    font-weight: 600;
    transition: background-color 0.2s;
    border-radius: 4px 0 0 4px;
}

/* Row Label Zone Shading (Greyscale) */
.heatmap-row-label.zone-night { background-color: rgba(0, 0, 0, 0.03); color: var(--secondary-text); }
.heatmap-row-label.zone-morning { background-color: rgba(0, 0, 0, 0.08); color: var(--primary-text); }
.heatmap-row-label.zone-day { background-color: rgba(0, 0, 0, 0.03); color: var(--secondary-text); }
.heatmap-row-label.zone-evening { background-color: rgba(0, 0, 0, 0.08); color: var(--primary-text); }

[data-theme="dark"] .heatmap-row-label.zone-night { background-color: rgba(255, 255, 255, 0.03); }
[data-theme="dark"] .heatmap-row-label.zone-morning { background-color: rgba(255, 255, 255, 0.08); }
[data-theme="dark"] .heatmap-row-label.zone-day { background-color: rgba(255, 255, 255, 0.03); }
[data-theme="dark"] .heatmap-row-label.zone-evening { background-color: rgba(255, 255, 255, 0.08); }

.heatmap-cell {
    height: 42px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.95rem; /* Large and readable */
    font-weight: 800;
    color: #000;
    border: 1px solid rgba(0,0,0,0.1);
    transition: transform 0.1s;
    box-shadow: inset 0 0 10px rgba(255,255,255,0.2);
}

.heatmap-cell:hover {
    transform: scale(1.05);
    z-index: 50;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

/* Prediction Distinction */
.heatmap-cell.forecast {
    opacity: 0.75;
    border: 2px dashed rgba(0,0,0,0.3);
    /* Subtle diagonal stripes for forecast */
    background-image: linear-gradient(135deg, rgba(255,255,255,0.1) 25%, transparent 25%, transparent 50%, rgba(255,255,255,0.1) 50%, rgba(255,255,255,0.1) 75%, transparent 75%, transparent);
    background-size: 8px 8px;
}

.heatmap-cell.current {
    box-shadow: 0 0 0 4px var(--background), 0 0 0 8px #00ffff, 0 0 20px #00ffff;
    position: relative;
    z-index: 20;
}

.legend-gradient {
    height: 12px;
    width: 250px;
    background: linear-gradient(to right, #22c55e, #eab308, #f97316, #ef4444);
    margin: 0 12px;
    border-radius: 6px;
}

.heatmap-legend { display: flex; align-items: center; font-size: 0.9rem; margin-top: 15px; font-weight: 600; }

.chart-container {
    width: 100%;
    height: 500px;
}

@media (max-width: 600px) {
    .chart-container { height: 350px; }
}

.chart-controls {
    display: flex;
    gap: 8px;
    margin-bottom: 12px;
}

.chart-controls button {
    background: var(--card-bg);
    border: 1px solid var(--border);
    color: var(--primary-text);
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
}

.window-table { width: 100%; border-collapse: collapse; margin-top: 10px; table-layout: auto; }
.window-table th { text-align: left; color: var(--secondary-text); font-size: 0.8rem; padding-bottom: 8px; padding-right: 8px; }
.window-table td { padding: 12px 8px 12px 0; border-top: 1px solid var(--border); font-weight: 500; white-space: nowrap; }
.window-table td:last-child { padding-right: 0; }
.window-table tr.active { background: rgba(0, 200, 255, 0.15); font-weight: 700; }

@media (max-width: 600px) {
    .chart-container { height: 350px; }
    .window-table th, .window-table td { font-size: 0.85rem; }
    .window-table td { padding: 10px 4px 10px 0; }
}

.confidence-box {
    text-align: center;
    padding: 15px;
    border-radius: 8px;
    font-weight: 700;
}

.confidence-box.green { background: #22c55e33; color: #22c55e; }
.confidence-box.yellow { background: #eab30833; color: #eab308; }
.confidence-box.red { background: #ef444433; color: #ef4444; }

.disclaimer { font-size: 0.85rem; color: var(--secondary-text); margin-bottom: 16px; }

.bullet-list { margin-left: 20px; font-size: 0.9rem; }
.bullet-list li { margin-bottom: 6px; }

.pricing-formula {
    background: var(--background);
    padding: 15px;
    border-radius: 8px;
    margin: 10px 0;
    font-size: 0.95rem;
    border: 1px dashed var(--border);
}

.pricing-formula code {
    color: var(--link-accent);
    font-weight: bold;
}

.footer {
    text-align: center;
    color: var(--secondary-text);
    font-size: 0.85rem;
    padding: 40px 0;
}