:root {
    --bg-color: #ffffff;
    --text-color: #333333;
    --card-bg: #f5f5f5;
    --accent-color: #007bff;
    --border-color: #dddddd;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #e0e0e0;
    --card-bg: #2d2d2d;
    --accent-color: #4dabf7;
    --border-color: #444444;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.btn-icon {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-color);
    padding: 8px;
    border-radius: 50%;
}

.btn-icon:hover {
    background-color: var(--card-bg);
}

.icon-sun { display: none; }
.icon-moon { display: block; }

[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }

.controls {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
    align-items: center;
}

#symbol-select {
    padding: 8px;
    border-radius: 4px;
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    color: var(--text-color);
}

.time-ranges {
    display: flex;
    gap: 5px;
    flex-wrap: wrap;
}

.time-ranges button {
    padding: 6px 12px;
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    color: var(--text-color);
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
}

.time-ranges button:hover {
    background-color: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.time-ranges button.active {
    background-color: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.chart-container {
    height: 600px;
    width: 100%;
    background-color: var(--card-bg);
    border-radius: 8px;
    padding: 10px;
    box-sizing: border-box;
}

#price-chart {
    width: 100%;
    height: 100%;
}

@media (max-width: 768px) {
    .chart-container {
        height: 400px;
    }
    
    .controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .time-ranges {
        justify-content: space-between;
    }
    
    .time-ranges button {
        flex: 1;
        text-align: center;
    }
}