:root {
    --bg: #f7f7f7;
    --text: #222;
    --accent: #2f4f6f;
    --accent-soft: #e3edf7;
    --card-bg: #ffffff;
    --border: #d0d0d0;
    --max-width: 1100px;
    --radius: 10px;
    --shadow: 0 2px 8px rgba(0,0,0,0.06);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

/* Header */
.site-header {
    background: var(--accent);
    color: white;
    padding: 1.5rem 0;
    box-shadow: var(--shadow);
}

.site-header h1 {
    margin: 0;
    font-family: "Merriweather", serif;
    font-size: 2rem;
    text-align: center;
}

/* Navigation */
.nav {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.nav a {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 999px;
    transition: background 0.2s;
    font-weight: 600;
}

.nav a:hover {
    background: rgba(255,255,255,0.2);
}

.nav a.active {
    background: rgba(255,255,255,0.3);
}

/* Main layout */
.main {
    max-width: var(--max-width);
    margin: 2rem auto;
    padding: 0 1.5rem;
}

/* Section */
.section {
    margin-bottom: 2.5rem;
}

.section-header h2 {
    font-family: "Merriweather", serif;
    font-size: 1.5rem;
    color: var(--accent);
    margin-bottom: 1rem;
}

/*Main Header*/
.main h1 {
    text-align: center;
    font-family: "Merriweather", serif;
    font-size: 2rem;
    color: var(--accent);
    margin-bottom: 1.5rem;
}

/* Lab blocks */
.lab-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
}

.lab-card h3 {
    margin-top: 0;
    color: var(--accent);
    font-size: 1.2rem;
}

.lab-card p {
    margin-bottom: 0.5rem;
}

/* Footer */
.site-footer {
    text-align: center;
    padding: 1.5rem;
    font-size: 0.9rem;
    color: #555;
    border-top: 1px solid var(--border);
    background: #fafafa;
}

/* Lab Menu Card */
.lab-menu-card {
    background: var(--accent-soft);
    border: 1px solid rgba(47, 79, 111, 0.15);
    border-radius: 12px;
    padding: 1.75rem 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 2.5rem;
}

.lab-menu-card p {
    font-size: 1rem;
    margin-bottom: 1.5rem;
    color: var(--text);
}

/* Button container */
.lab-menu-buttons {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

/* Individual buttons */
.lab-menu-button {
    display: block;
    text-align: center;
    background: var(--accent);
    color: #ffffff;
    padding: 0.75rem 1rem;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    transition: background 0.2s ease, transform 0.15s ease;
}

.lab-menu-button:hover {
    background: #3b5f80;
    transform: translateY(-2px);
}

/* Responsive: turn buttons into two columns on larger screens */
@media (min-width: 700px) {
    .lab-menu-buttons {
        grid-template-columns: 1fr 1fr;
    }
}

.lab-button {
    display: inline-block;
    background: var(--accent);
    color: #ffffff;
    padding: 0.6rem 1.1rem;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    margin-top: 0.75rem;
    transition: background 0.2s ease, transform 0.15s ease;
}

.lab-button:hover {
    background: #3b5f80;
    transform: translateY(-2px);
}