:root {
    --bg-color: #0d1117;
    --card-bg: rgba(22, 27, 34, 0.7);
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --accent-color: #58a6ff;
    --success-color: #238636;
    --glass-border: 1px solid rgba(240, 246, 252, 0.1);
}

* {
    box-sizing: border_box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    min-height: 100vh;
    padding: 2rem;
    background-image: radial-gradient(circle at 10% 20%, rgba(88, 166, 255, 0.1) 0%, transparent 20%),
                      radial-gradient(circle at 90% 80%, rgba(35, 134, 54, 0.1) 0%, transparent 20%);
}

.container {
    width: 100%;
    max-width: 1200px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

header {
    text-align: center;
    margin-bottom: 1rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 300;
    margin-bottom: 0.5rem;
    background: linear-gradient(90deg, var(--accent-color), #bc8cff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

input {
    padding: 0.8rem 1.2rem;
    border-radius: 8px;
    border: var(--glass-border);
    background: rgba(13, 17, 23, 0.8);
    color: var(--text-primary);
    font-size: 1rem;
    outline: none;
    transition: border-color 0.3s;
}

input:focus {
    border-color: var(--accent-color);
}

button {
    padding: 0.8rem 1.5rem;
    border-radius: 8px;
    border: none;
    background-color: var(--success-color);
    color: white;
    font-weight: bold;
    cursor: pointer;
    transition: transform 0.2s, opacity 0.2s;
    font-size: 1rem;
}

button:hover {
    transform: translateY(-2px);
    opacity: 0.9;
}

button#btn-btc { background-color: #f7931a; }
button#btn-eth { background-color: #627eea; }

.dashboard {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 1.5rem;
}

.card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border: var(--glass-border);
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
}

.stats h2 {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.price-display {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--text-primary);
}

.price-change {
    margin-top: 0.5rem;
    font-size: 1rem;
}

.chart-container {
    position: relative;
    height: 400px;
    width: 100%;
}

footer {
    text-align: center;
    color: var(--text-secondary);
    margin-top: 2rem;
    font-size: 0.8rem;
}

@media (max-width: 768px) {
    .dashboard {
        grid-template-columns: 1fr;
    }
}