:root {
    --primary-color: #e74c3c;
    --secondary-color: #2c3e50;
    --accent-color: #3498db;
    --bg-color: #f4f7f6;
    --card-bg: #ffffff;
    --text-color: #2d3436;
    --font-main: 'Noto Sans TC', sans-serif;
}

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

body {
    font-family: var(--font-main);
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    min-height: 100vh;
    padding: 20px;
}

.app-container {
    width: 100%;
    max-width: 100%; /* Changed from 900px to 100% for full width */
    display: flex;
    flex-direction: column;
    gap: 20px;
    padding: 0 20px; /* Add some padding */
}

header {
    text-align: center;
    margin-bottom: 10px;
}

h1 {
    font-size: 2rem;
    color: var(--secondary-color);
    margin-bottom: 5px;
}

.subtitle {
    color: #7f8c8d;
    font-size: 1rem;
}

.visualization-card {
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.svg-container {
    width: 100%;
    background: #fff0f0; /* Light blood bg */
    border-bottom: 1px solid #eee;
    position: relative;
}

svg {
    display: block;
    width: 100%;
    height: auto;
    max-height: 400px;
}

.controls {
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background: #eee;
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary-color);
    width: 20%; /* Initial step 1/5 */
    transition: width 0.3s ease;
}

.step-buttons {
    display: flex;
    justify-content: space-between;
    gap: 10px;
    flex-wrap: wrap;
}

.step-btn {
    flex: 1;
    padding: 10px 5px;
    border: none;
    background: #f1f2f6;
    color: #7f8c8d;
    border-radius: 8px;
    cursor: pointer;
    font-family: var(--font-main);
    font-weight: 600;
    font-size: 0.9rem;
    transition: all 0.2s ease;
    min-width: 120px;
}

.step-btn:hover {
    background: #e1e2e6;
}

.step-btn.active {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 4px 12px rgba(231, 76, 60, 0.3);
}

.info-panel {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 12px;
    border-left: 5px solid var(--primary-color);
}

.info-panel h2 {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: var(--secondary-color);
}

.info-panel p {
    line-height: 1.6;
    color: #57606f;
}

/* Animation Classes */
.pulse {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.1); opacity: 0.8; }
    100% { transform: scale(1); opacity: 1; }
}