:root {
    --dark-bg: #0a0a0a;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --accent: #00f3ff;
    --text-primary: rgba(255, 255, 255, 0.9);
}

body {
    font-family: 'Segoe UI', sans-serif;
    margin: 0;
    padding: 20px;
    background: var(--dark-bg);
    color: var(--text-primary);
    min-height: 100vh;
}

.container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 20px;
    padding: 20px;
}

.chart-box {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    border-radius: 15px;
    padding: 15px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    cursor: pointer;
    transition: transform 0.3s ease;
    min-height: 400px;
}

.chart-box:hover {
    transform: translateY(-5px);
}

.header {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 20px;
    padding: 20px;
    background: var(--glass-bg);
    border-radius: 12px;
}

.upload-btn {
    background: rgba(0, 243, 255, 0.1);
    padding: 12px 25px;
    border-radius: 8px;
    cursor: pointer;
    border: 2px solid var(--accent);
    color: var(--accent);
    font-weight: 600;
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 2000;
}

.loading-bar {
    width: 300px;
    height: 4px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 2px;
    overflow: hidden;
    position: relative;
}

.loading-progress {
    width: 100%;
    height: 100%;
    background: #00f3ff;
    position: absolute;
    left: -100%;
    animation: loading 2s infinite;
}

@keyframes loading {
    0% { left: -100%; }
    100% { left: 100%; }
}

#error-message {
    color: #ff4444;
    padding: 10px;
    display: none;
    background: rgba(255, 68, 68, 0.1);
    border-radius: 8px;
    margin: 20px 0;
}