:root {
    color-scheme: light dark;
    --page-max-width: 960px;
    --surface-color: rgba(255, 255, 255, 0.9);
    --accent-color: #005596;
    --border-color: rgba(0, 0, 0, 0.1);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: linear-gradient(135deg, #e6f0ff, #f5f9ff);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 3rem 1rem;
    color: #1f2d3d;
}

main {
    width: 100%;
    max-width: var(--page-max-width);
    background: var(--surface-color);
    backdrop-filter: blur(6px);
    border-radius: 16px;
    border: 1px solid var(--border-color);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.08);
    padding: 2.5rem 3rem;
}

h1 {
    margin-top: 0;
    font-size: 2rem;
    color: var(--accent-color);
    letter-spacing: 0.02em;
}

p.description {
    margin-top: 0.5rem;
    margin-bottom: 2rem;
    color: rgba(31, 45, 61, 0.8);
}

.student-section {
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.25rem 1.5rem;
    margin-bottom: 1.5rem;
    background: rgba(255, 255, 255, 0.85);
}

.student-section h2 {
    margin: 0 0 0.75rem;
    font-size: 1.3rem;
    color: var(--accent-color);
}

.student-section table {
    width: 100%;
    border-collapse: collapse;
}

.student-section th,
.student-section td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

.student-section tbody tr:nth-child(even) {
    background: rgba(0, 0, 0, 0.02);
}

.student-section td.empty {
    color: rgba(31, 45, 61, 0.4);
    font-style: italic;
}

.student-section .empty-message {
    margin: 0.5rem 0 0;
    color: rgba(31, 45, 61, 0.6);
    font-style: italic;
}

@media (max-width: 640px) {
    main {
        padding: 1.75rem;
    }

    h1 {
        font-size: 1.5rem;
    }

    .student-section th,
    .student-section td {
        padding: 0.7rem 0.5rem;
        font-size: 0.95rem;
    }
}