:root {
    --bg-color: #f5f3ef;
    --card-bg: #ffffff;
    --text-primary: #1a1a2e;
    --text-secondary: #555566;
    --accent-primary: #8a1b3d;
    /* Sapienza Red */
    --accent-secondary: #b8922e;
    /* Warm Gold (slightly deeper for light bg) */
    --success: #0d9668;
    --gradient-main: linear-gradient(135deg, #8a1b3d 0%, #c9a84c 100%);
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
    --border-color: rgba(0, 0, 0, 0.1);
    --shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
}

body {
    margin: 0;
    font-family: var(--font-main);
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
}

/* Header */
header {
    padding: 2rem 5%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    backdrop-filter: blur(10px);
    background: rgba(245, 243, 239, 0.9);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
}

.logo {
    font-weight: 800;
    font-size: 1.5rem;
    background: var(--gradient-main);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 8rem 2rem;
    position: relative;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('images/hero_bg.png');
    background-size: cover;
    background-position: center;
    opacity: 0.08;
    z-index: 0;
    mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 1) 50%, rgba(0, 0, 0, 0));
    -webkit-mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 1) 50%, rgba(0, 0, 0, 0));
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 4rem;
    font-weight: 900;
    margin-bottom: 1rem;
    background: var(--gradient-main);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: fadeIn 1s ease-out;
}

.hero p {
    font-size: 1.5rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto;
}

/* Google Classroom Banner */
.classroom-banner {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem 2.5rem;
    box-shadow: var(--shadow);
    margin-bottom: 1rem;
}

.classroom-icon {
    flex-shrink: 0;
    width: 64px;
    height: 64px;
    border-radius: 14px;
    background: rgba(138, 27, 61, 0.08);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-primary);
}

.classroom-info {
    flex: 1;
}

.classroom-info h3 {
    margin: 0 0 0.25rem 0;
    font-size: 1.25rem;
    color: var(--text-primary);
}

.classroom-info p {
    margin: 0 0 0.5rem 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.classroom-code {
    font-size: 0.85rem;
    color: var(--text-secondary);
    background: rgba(138, 27, 61, 0.06);
    padding: 0.2rem 0.6rem;
    border-radius: 6px;
}

.classroom-code strong {
    color: var(--accent-primary);
    font-family: 'SF Mono', 'Fira Code', monospace;
    letter-spacing: 0.05em;
}

.classroom-btn {
    flex-shrink: 0;
    display: inline-block;
    background: var(--accent-primary);
    color: #ffffff;
    text-decoration: none;
    padding: 0.75rem 1.75rem;
    border-radius: 10px;
    font-weight: 700;
    font-size: 0.95rem;
    transition: background 0.2s ease, transform 0.2s ease;
}

.classroom-btn:hover {
    background: #a02248;
    transform: translateY(-2px);
}

@media (max-width: 700px) {
    .classroom-banner {
        flex-direction: column;
        text-align: center;
    }
}

/* Course Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 3rem;
    text-align: center;
}

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

.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow);
}

.card-image {
    width: 100%;
    height: auto;
    overflow: hidden;
    position: relative;
    border-bottom: 1px solid var(--border-color);
}

.card-image img {
    width: 100%;
    height: auto;
    display: block;
    transition: transform 0.3s ease;
}

.card:hover .card-image img {
    transform: scale(1.05);
}

.card-content {
    padding: 2rem;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.card h3 {
    font-size: 1.5rem;
    margin-top: 0;
    color: var(--accent-primary);
}

.card .hours {
    display: inline-block;
    background: rgba(138, 27, 61, 0.1);
    color: var(--accent-primary);
    padding: 0.25rem 0.75rem;
    border-radius: 999px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.topic-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.topic-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.exercise-highlight {
    margin-top: 1.5rem;
    padding: 1rem;
    background: rgba(13, 150, 104, 0.06);
    border-radius: 8px;
    border-left: 3px solid var(--success);
}

.exercise-highlight h4 {
    margin: 0 0 0.5rem 0;
    color: var(--success);
    font-size: 1rem;
}

footer {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
    margin-top: 4rem;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Team Section */
.team-grid {
    display: flex;
    justify-content: center;
    gap: 4rem;
    flex-wrap: nowrap;
    margin-top: 2rem;
}

@media (max-width: 600px) {
    .team-grid {
        flex-direction: column;
        align-items: center;
        gap: 2rem;
    }
}

.team-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2.5rem;
    text-align: center;
    width: 250px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    box-shadow: var(--shadow);
}

.team-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    border-color: var(--accent-primary);
}

.team-avatar {
    width: 100px;
    height: 100px;
    margin: 0 auto 1.5rem auto;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    padding: 3px;
    /* border width */
    display: flex;
    align-items: center;
    justify-content: center;
}

.avatar-placeholder {
    width: 100%;
    height: 100%;
    background: var(--bg-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
}

.team-card h3 {
    margin: 0.5rem 0;
    color: var(--text-primary);
    font-size: 1.25rem;
}

.role {
    color: var(--accent-primary);
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.bio-link {
    display: inline-block;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.3s ease, border-color 0.3s ease;
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 99px;
}

.bio-link:hover {
    color: var(--accent-primary);
    border-color: var(--accent-primary);
}

/* Schedule Section */
.schedule-container {
    overflow-x: auto;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    background: var(--card-bg);
    margin-top: 2rem;
    box-shadow: var(--shadow);
}

.schedule-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 600px;
}

.schedule-table th,
.schedule-table td {
    padding: 1.25rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.schedule-table th {
    background: rgba(0, 0, 0, 0.03);
    color: var(--text-secondary);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 0.05em;
}

.schedule-table tr:last-child td {
    border-bottom: none;
}

.schedule-table tr:hover {
    background: rgba(138, 27, 61, 0.02);
}

.part-header td {
    background: rgba(138, 27, 61, 0.06);
    color: var(--accent-primary);
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    padding: 1rem 1.25rem;
    font-size: 0.9rem;
}

.tag {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 99px;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
}

.tag.lecture {
    background: rgba(138, 27, 61, 0.1);
    color: #8a1b3d;
    border: 1px solid rgba(138, 27, 61, 0.25);
}

.tag.lab {
    background: rgba(184, 146, 46, 0.1);
    color: #96780f;
    border: 1px solid rgba(184, 146, 46, 0.25);
}

.tag.holiday {
    background: rgba(220, 60, 60, 0.08);
    color: #c0392b;
    border: 1px solid rgba(220, 60, 60, 0.2);
}

.tag.exercise {
    background: rgba(13, 150, 104, 0.1);
    color: #0d9668;
    border: 1px solid rgba(13, 150, 104, 0.25);
}

.holiday td {
    opacity: 0.6;
    font-style: italic;
}