/* General Styling */
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; background-color: #f4f7f6; color: #333; margin: 0; line-height: 1.6; }
.container { max-width: 1400px; margin: 20px auto; padding: 20px; background-color: #fff; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.05); }
h1, h2, h3 { color: #2c3e50; }
a { color: #3498db; text-decoration: none; }
a:hover { text-decoration: underline; }
button, .btn { background-color: #3498db; color: #fff; border: none; padding: 10px 15px; border-radius: 4px; cursor: pointer; font-size: 1em; transition: background-color 0.2s; }
button:hover { background-color: #2980b9; }
button.danger { background-color: #e74c3c; }
button.danger:hover { background-color: #c0392b; }
input[type="text"], input[type="password"], input[type="date"], input[type="month"], select, textarea { width: 100%; padding: 10px; margin-bottom: 10px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; }
form { margin-bottom: 20px; }

/* Header and Navigation */
header { background-color: #2c3e50; color: #fff; padding: 10px 0; }
header nav { display: flex; align-items: center; }
header nav a { color: #fff; padding: 10px 15px; border-radius: 4px; }
header nav a:hover, header nav a.active { background-color: #34495e; }
.user-info { margin-left: auto; padding-right: 15px; }
.logout-btn { background-color: #e74c3c; } .logout-btn:hover { background-color: #c0392b; }

/* Messages */
.message { padding: 15px; margin-bottom: 20px; border-radius: 4px; border: 1px solid; }
.message.success { background-color: #d4edda; color: #155724; border-color: #c3e6cb; }
.message.error { background-color: #f8d7da; color: #721c24; border-color: #f5c6cb; }

/* Login Container */
.login-container { max-width: 400px; margin: 100px auto; padding: 30px; background-color: #fff; border-radius: 8px; box-shadow: 0 4px 15px rgba(0,0,0,0.1); }

/* Class List */
.class-list { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 20px; }
.class-item { background-color: #ecf0f1; padding: 10px 20px; border-radius: 20px; transition: background-color 0.2s; }
.class-item:hover { background-color: #bdc3c7; }
.class-item.active { background-color: #3498db; color: #fff; }

/* Attendance Table */
.attendance-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 15px; }
.table-container { overflow-x: auto; }
.attendance-table { width: 100%; border-collapse: collapse; font-size: 0.9em; }
.attendance-table th, .attendance-table td { border: 1px solid #ddd; padding: 5px; text-align: center; min-width: 60px; }
.attendance-table th { background-color: #f2f2f2; }
.attendance-table tbody tr:nth-child(even) { background-color: #f9f9f9; }
.attendance-table tbody td:first-child, .attendance-table th:first-child { text-align: left; position: sticky; left: 0; background: #fff; z-index: 1; min-width: 150px; }
.attendance-table th.weekend { background-color: #fbeaea; }
.attendance-table th.holiday { background-color: #fff0b3; border: 2px solid #e74c3c; }
.attendance-table tfoot .summary-row td { font-weight: bold; background-color: #ecf0f1; }
.attendance-table tfoot .summary-label { text-align: right; padding-right: 10px; }
.controls { margin-bottom: 15px; display: flex; gap: 10px; align-items: center; }
.controls.bottom-controls { margin-top: 15px; justify-content: flex-end; }
.save-btn { background-color: #27ae60; } .save-btn:hover { background-color: #229954; }

/* Admin Panel */
.admin-nav { display: flex; border-bottom: 2px solid #ddd; margin-bottom: 20px; }
.admin-nav a { padding: 10px 20px; color: #333; border-bottom: 2px solid transparent; }
.admin-nav a.active { border-bottom-color: #3498db; font-weight: bold; }
.list-item { display: flex; justify-content: space-between; align-items: center; padding: 15px; border-bottom: 1px solid #eee; }
.list-item:nth-child(even) { background-color: #f9f9f9; }
.list-item .actions { display: flex; gap: 10px; }
.list-item .actions form { margin: 0; }
.student-list { padding-left: 30px; border-left: 2px solid #3498db; margin: 10px 0 20px 10px; }
.sub-item { padding: 10px; }
.inline-form { display: flex; gap: 10px; align-items: center; margin-bottom: 15px; }
.inline-form input { width: auto; flex-grow: 1; }
.message-item { flex-direction: column; align-items: flex-start; }

/* Export and Filter Form */
.filter-form { display: flex; gap: 15px; align-items: center; padding: 15px; background: #f9f9f9; border-radius: 8px; margin-bottom: 20px; }
.filter-form label { font-weight: bold; }
.filter-form input, .filter-form select { width: auto; }
.report-table { width: 100%; border-collapse: collapse; margin-top: 20px; }
.report-table th, .report-table td { border: 1px solid #ddd; padding: 12px; text-align: left; }
.report-table th { background-color: #2c3e50; color: #fff; }

/* Modal */
.modal { display: none; position: fixed; z-index: 100; left: 0; top: 0; width: 100%; height: 100%; overflow: auto; background-color: rgba(0,0,0,0.5); }
.modal-content { background-color: #fefefe; margin: 15% auto; padding: 20px; border: 1px solid #888; width: 80%; max-width: 500px; border-radius: 8px; }
.modal-content textarea { height: 120px; }
.close { color: #aaa; float: right; font-size: 28px; font-weight: bold; }
.close:hover, .close:focus { color: black; text-decoration: none; cursor: pointer; }