body {
    font-family: Arial, sans-serif;
    margin: 0;
    background-color: #f4f6f8;
}

nav {
    background-color: #1f2937;
    padding: 15px;
}

nav a {
    color: white;
    margin-right: 20px;
    text-decoration: none;
}

.container {
    padding: 40px;
}

.card {
    background: white;
    padding: 25px;
    border-radius: 10px;
}

/* ===== 미세먼지 실습 ===== */
.dust-row { display: flex; gap: 16px; flex-wrap: wrap; margin: 16px 0; }
.dust-box { flex: 1; min-width: 160px; border: 4px solid #d1d5db; border-radius: 10px; padding: 16px; text-align: center; }
.dust-box .label { color: #6b7280; }
.dust-box .value { font-size: 28px; font-weight: bold; margin: 8px 0; }
.dust-box .grade { font-size: 20px; }
.json { background: #111827; color: #e5e7eb; padding: 16px; border-radius: 8px; overflow-x: auto; font-size: 13px; }
.hint { color: #6b7280; font-size: 14px; }
.error { color: #ef4444; }
.credit { color: #9ca3af; font-size: 12px; margin-top: 12px; }
button { padding: 8px 16px; border: none; border-radius: 6px; background: #1f2937; color: white; cursor: pointer; }

/* ===== GET·POST 실습 ===== */
.form-row { display: flex; gap: 12px; flex-wrap: wrap; margin: 12px 0; }
.form-row input { padding: 6px; border: 1px solid #d1d5db; border-radius: 6px; width: 120px; }
.compare { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 16px; margin-top: 16px; }
.compare .json { max-height: 420px; overflow-y: auto; }

/* ===== 학생 DB 실습 ===== */
.search-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; margin: 16px 0; }
.search-grid label { display: flex; flex-direction: column; gap: 4px; font-size: 14px; color: #374151; }
.search-grid input, .search-grid select { padding: 7px; border: 1px solid #d1d5db; border-radius: 6px; font-size: 14px; }
.search-buttons { display: flex; gap: 8px; align-items: flex-end; }
button.secondary { background: #e5e7eb; color: #111827; }
button:disabled { opacity: 0.4; cursor: default; }
.table-wrap { overflow-x: auto; }
.data-table { width: 100%; border-collapse: collapse; font-size: 14px; white-space: nowrap; }
.data-table th, .data-table td { padding: 8px 10px; border-bottom: 1px solid #e5e7eb; text-align: left; }
.data-table th { background: #f3f4f6; }
.data-table tr:hover td { background: #f9fafb; }
.data-table .empty { text-align: center; color: #6b7280; padding: 24px; }
.pager { display: flex; gap: 12px; align-items: center; justify-content: center; margin: 16px 0; }