:root {
    --primary-color: #0056b3;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --text-color: #333;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Navigation */
nav {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

nav h1 {
    margin: 0;
    font-size: 1.5rem;
}

.nav-links {
    display: flex;
    gap: 10px;
}

.nav-links button {
    background: none;
    border: 1px solid rgba(255,255,255,0.5);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    margin-left: 10px;
    font-size: 0.9rem;
}
.nav-links button:hover {
    background: rgba(255,255,255,0.1);
}

/* Container */
.container {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem; /* Reduced top/bottom padding */
    width: 100%;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
}

/* Views */
.view {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}
.view.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Welcome Page */
.welcome-hero {
    text-align: center;
    margin-bottom: 3rem;
    margin-top: 2rem;
}
.welcome-hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}
.welcome-hero p {
    font-size: 1.2rem;
    color: #666;
    max-width: 600px;
    margin: 0 auto;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform 0.2s, box-shadow 0.2s;
    cursor: pointer;
    border: 1px solid #eee;
    text-decoration: none;
    color: inherit;
    display: block;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 12px rgba(0,0,0,0.1);
    border-color: var(--primary-color);
}

.card h3 {
    margin-top: 0;
    color: var(--primary-color);
}

/* Simulation Controls */
.controls-panel {
    background: var(--card-bg);
    padding: 1rem 1.5rem; /* Reduced padding */
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    margin-bottom: 0.5rem; /* REDUCED SPACE between controls and plot */
    border: 1px solid #e0e0e0;
}

.controls-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem; /* Reduced gap */
}

.control-group {
    display: flex;
    flex-direction: column;
}

.control-group label {
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.3rem;
    color: #555;
}

.control-group input, .control-group select {
    padding: 0.4rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 0.95rem;
}

.control-group input:focus, .control-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(0,86,179,0.1);
}

.play-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 4px;
    transition: background-color 0.2s;
}

.play-btn:hover {
    background-color: #004494;
}

/* Plot Area */
#plot-container {
    background: var(--card-bg);
    border-radius: 8px;
    padding: 0; /* Removed padding */
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    /* min-height removed to allow hugging the content */
    position: relative;
    overflow: hidden;
}

/* Make sure the pyodide plot fills the container */
#plot-container div {
    width: 100%;
    display: flex;
    justify-content: center;
}

/* Status Bar */
#status-bar {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: #333;
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1000;
}

.spinner {
    display: inline-block;
    width: 10px;
    height: 10px;
    border: 2px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
    margin-right: 10px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.hidden { display: none !important; }