:root{--color-bg:#f4f6f8;--color-surface:#fff;--color-border:#e2e5e9;--color-primary:#0088b0;--color-primary-dark:#006786;--color-text:#1a1d23;--color-muted:#6b7280;--color-success:#16a34a;--color-danger:#dc2626;--color-warning:#b45309;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif}*{box-sizing:border-box}body{background:var(--color-bg);color:var(--color-text);margin:0}a{color:var(--color-primary);text-decoration:none}a:hover{text-decoration:underline}button{cursor:pointer;background:var(--color-primary);color:#fff;border:none;border-radius:6px;padding:10px 18px;font-size:14px;font-weight:600}button:hover{background:var(--color-primary-dark)}button:disabled{background:var(--color-muted);cursor:not-allowed}input,textarea{border:1px solid var(--color-border);border-radius:6px;width:100%;padding:10px 12px;font-family:inherit;font-size:14px}.auth-page{justify-content:center;align-items:center;min-height:100vh;padding:16px;display:flex}.auth-card{background:var(--color-surface);border-radius:12px;flex-direction:column;gap:14px;width:100%;max-width:360px;padding:32px;display:flex;box-shadow:0 4px 24px #0000000f}.auth-logo{object-fit:contain;width:56px;height:56px;margin:0 auto 4px;display:block}.auth-card h1{text-align:center;margin:0;font-size:20px}.auth-subtitle{color:var(--color-muted);text-align:center;margin:0 0 8px;font-size:14px}.auth-card label{color:var(--color-muted);flex-direction:column;gap:6px;font-size:13px;font-weight:600;display:flex}.auth-error{color:var(--color-danger);background:#fef2f2;border:1px solid #fecaca;border-radius:6px;padding:10px 12px;font-size:13px}.app-layout{flex-direction:column;min-height:100vh;display:flex}.app-header{background:var(--color-surface);border-bottom:1px solid var(--color-border);align-items:center;gap:24px;padding:14px 24px;display:flex}.app-logo{color:var(--color-text);align-items:center;gap:8px;font-size:15px;font-weight:700;display:flex}.app-logo-img{object-fit:contain;width:28px;height:28px}.app-nav{flex:1;gap:18px;display:flex}.app-nav a{color:var(--color-text);font-weight:500}.app-user{align-items:center;gap:12px;font-size:14px;display:flex}.app-user button{color:var(--color-danger);border:1px solid var(--color-danger);background:0 0;padding:6px 14px}.app-user button:hover{background:#fef2f2}.app-main{flex:1;width:100%;max-width:900px;margin:0 auto;padding:24px 16px 60px}.page-loading,.page-error{text-align:center;color:var(--color-muted);padding:40px}.page-error{color:var(--color-danger)}.dashboard h1{margin-top:0}.course-block{margin-bottom:32px}.month-block{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;margin-bottom:12px;padding:16px 20px}.month-block--current{border-color:var(--color-primary)}.month-header{justify-content:space-between;align-items:center;display:flex}.month-header h3{margin:0}.month-progress{color:var(--color-muted);font-size:13px}.month-locked{color:var(--color-muted);font-size:14px}.lesson-list{flex-direction:column;gap:8px;margin:12px 0 0;padding:0;list-style:none;display:flex}.lesson-list li{font-size:14px}.lesson-item--locked{color:var(--color-muted)}.back-link{margin-bottom:12px;font-size:13px;display:inline-block}.lesson-video{border-radius:10px;margin:16px 0;padding-top:56.25%;position:relative;overflow:hidden}.lesson-video iframe{border:0;width:100%;height:100%;position:absolute;inset:0}.lesson-content{line-height:1.7}.lesson-code{color:#e5e7eb;background:#1a1d23;border-radius:8px;padding:16px;overflow-x:auto}.lesson-attachments ul{padding-left:20px}.lesson-homework-task,.homework-submission,.submission-status{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;margin-top:20px;padding:16px 20px}.homework-submission form{flex-direction:column;gap:12px;margin-top:12px;display:flex}.homework-submission button{align-self:flex-start}.ai-comment{border-left:3px solid var(--color-primary);background:#eff6ff;border-radius:6px;margin-top:12px;padding:12px}.grades-average{align-items:baseline;gap:10px;margin-bottom:24px;display:flex}.grades-average-value{font-size:40px;font-weight:700}.grades-average-label{color:var(--color-muted)}.grades-table{border-collapse:collapse;background:var(--color-surface);border-radius:10px;width:100%;overflow:hidden}.grades-table th,.grades-table td{border-bottom:1px solid var(--color-border);text-align:left;padding:10px 14px;font-size:14px}.grades-value{font-weight:700}.exam-card{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;justify-content:space-between;align-items:center;gap:16px;margin-bottom:12px;padding:16px 20px;display:flex}.exam-card h3{margin:0 0 4px}.exam-card-meta{color:var(--color-muted);margin:0;font-size:13px}.exam-card-hint{color:var(--color-warning);margin:6px 0 0;font-size:13px}.exam-card-hint--danger{color:var(--color-danger)}.exam-take{max-width:760px;margin:0 auto;padding:24px 16px 80px}.exam-take--privacy-blur{filter:blur(12px);pointer-events:none;-webkit-user-select:none;user-select:none}.exam-overlay{z-index:1000;background:#0f1115eb;justify-content:center;align-items:center;padding:16px;display:flex;position:fixed;inset:0}.exam-overlay-card{background:var(--color-surface);text-align:center;border-radius:12px;max-width:420px;padding:32px}.exam-overlay-card h2{margin-top:0}.exam-overlay-card button{margin-top:12px}.exam-overlay--lock{z-index:1100}.exam-header{background:var(--color-bg);z-index:10;justify-content:space-between;align-items:center;gap:16px;padding:8px 0;display:flex;position:sticky;top:0}.exam-header h1{margin:0;font-size:20px}.exam-timer{font-variant-numeric:tabular-nums;background:var(--color-surface);border:1px solid var(--color-border);border-radius:8px;padding:6px 14px;font-size:22px;font-weight:700}.exam-progress-label{color:var(--color-muted);margin:4px 0 20px;font-size:13px}.exam-question{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;margin-bottom:14px;padding:18px 20px}.exam-question h3{margin-top:0;font-size:16px}.exam-choices{flex-direction:column;gap:10px;margin-top:10px;display:flex}.exam-choice{cursor:pointer;align-items:center;gap:10px;font-size:14px;font-weight:400;display:flex}.exam-choice input{width:auto}.exam-submit{width:100%;margin-top:12px;padding:14px;font-size:16px}.exam-result-score{border-radius:12px;flex-direction:column;align-items:center;gap:6px;margin:20px 0;padding:32px;display:flex}.exam-result-score--passed{color:var(--color-success);background:#f0fdf4}.exam-result-score--failed{color:var(--color-danger);background:#fef2f2}.exam-result-percentage{font-size:48px;font-weight:700}.exam-result-pending{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;margin:20px 0;padding:24px}.pending-badge{color:var(--color-warning);vertical-align:middle;background:#fffbeb;border:1px solid #fde68a;border-radius:6px;margin-left:12px;padding:3px 10px;font-size:13px;font-weight:600;display:inline-block}.group-card-grid{grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:14px;margin-bottom:28px;display:grid}.group-card{background:var(--color-surface);border:1px solid var(--color-border);color:var(--color-text);border-left:4px solid #888;border-radius:10px;padding:16px 18px;display:block}.group-card:hover{text-decoration:none;box-shadow:0 2px 10px #0000000f}.group-card-top{justify-content:space-between;align-items:center;margin-bottom:6px;display:flex}.group-card-direction{color:var(--color-muted);text-transform:uppercase;letter-spacing:.02em;font-size:12px}.group-card h3{margin:0 0 10px}.group-card-badge{border-radius:5px;padding:3px 8px;font-size:11px;font-weight:700}.group-card-badge--accent{color:var(--color-primary);background:#eff6ff}.group-card-badge--ok{color:var(--color-success);background:#f0fdf4}.group-card-badge--warn{color:var(--color-warning);background:#fffbeb}.group-card-badge--neutral{color:var(--color-muted);background:#f3f4f6}.group-card-progress-bar{background:#eee;border-radius:4px;height:6px;overflow:hidden}.group-card-progress-fill{background:var(--color-primary);height:100%}.group-card-detail{color:var(--color-muted);margin:8px 0 0;font-size:13px}.group-detail-header{flex-wrap:wrap;align-items:center;gap:16px;display:flex}.group-detail-header h1{flex:1;margin:4px 0}.attendance-board-link{background:var(--color-surface);border:1px solid var(--color-border);border-radius:8px;padding:8px 14px;font-size:14px;font-weight:600}.group-info-grid{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:14px;margin:16px 0 24px;padding:18px 20px;display:grid}.group-info-grid>div{flex-direction:column;gap:3px;display:flex}.group-info-label{text-transform:uppercase;letter-spacing:.03em;color:var(--color-muted);font-size:11px}.group-tabs{border-bottom:1px solid var(--color-border);gap:4px;margin-bottom:16px;display:flex}.group-tabs button{color:var(--color-muted);background:0 0;border-radius:0;padding:10px 16px;font-weight:600}.group-tabs button.active{color:var(--color-primary);border-bottom:2px solid var(--color-primary)}.group-students-table{border-collapse:collapse;background:var(--color-surface);border-radius:10px;width:100%;overflow:hidden}.group-students-table th,.group-students-table td{border-bottom:1px solid var(--color-border);text-align:left;padding:10px 14px;font-size:14px}.balance-due{color:var(--color-danger);font-weight:600}.balance-ok{color:var(--color-success)}.attendance-board-header{align-items:center;gap:16px;margin-bottom:12px;display:flex}.attendance-board-header h1{flex:1;margin:0}.attendance-board-header select{width:auto}.attendance-legend{color:var(--color-muted);flex-wrap:wrap;gap:16px;margin-bottom:16px;font-size:13px;display:flex}.attendance-legend-item{align-items:center;gap:6px;display:flex}.att-dot{border-radius:50%;width:10px;height:10px;display:inline-block}.attendance-table-wrap{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;overflow-x:auto}.attendance-table{border-collapse:collapse;font-size:13px}.attendance-table th,.attendance-table td{border-bottom:1px solid var(--color-border);text-align:center;white-space:nowrap;padding:8px 10px}.attendance-sticky-col{background:var(--color-surface);z-index:1;position:sticky;left:0;text-align:left!important}.att-dot-btn{border:1px solid var(--color-border);color:#fff;background:#f3f4f6;border-radius:50%;width:28px;height:28px;padding:0;font-size:12px;font-weight:700}.att-dot-btn--future{opacity:.3;cursor:not-allowed}.cell-popup{background:var(--color-surface);border-radius:12px;width:100%;max-width:360px;padding:24px}.cell-popup h3{margin-top:0}.cell-popup-statuses{flex-direction:column;gap:8px;margin-bottom:14px;display:flex}.status-choice{background:var(--color-bg);border:2px solid var(--color-border);color:var(--color-text);border-radius:8px;align-items:center;gap:8px;padding:8px 12px;font-size:14px;font-weight:500;display:flex}.status-choice--active{background:#eff6ff}.cell-popup-grades{gap:8px;margin-bottom:10px;display:flex}.grade-choice{background:var(--color-bg);color:var(--color-text);border:1px solid var(--color-border);flex:1;padding:8px 0;font-weight:700}.grade-choice--active{background:var(--color-primary);color:#fff}.grade-choice:disabled{opacity:.4}.cell-popup-hint{color:var(--color-muted);margin:0 0 10px;font-size:12px}.cell-popup-actions{gap:8px;margin-top:14px;display:flex}.cell-popup-clear,.cell-popup-close{color:var(--color-muted);border:1px solid var(--color-border);background:0 0}.group-detail-actions{flex-wrap:wrap;gap:8px;display:flex}.secondary-btn{background:var(--color-surface);color:var(--color-text);border:1px solid var(--color-border);border-radius:8px;padding:8px 14px;font-size:14px;font-weight:600;display:inline-block}a.secondary-btn:hover{text-decoration:none}.archived-tag{color:var(--color-muted);vertical-align:middle;background:#f3f4f6;border-radius:5px;margin-left:10px;padding:3px 8px;font-size:12px;font-weight:700;display:inline-block}.monitor-tag{color:var(--color-warning);margin-left:8px;font-size:12px}.add-student-row{gap:8px;margin-bottom:14px;display:flex}.add-student-row select{max-width:280px}.row-menu-cell{text-align:right;position:relative}.row-menu-trigger{color:var(--color-muted);background:0 0;border:none;padding:2px 8px;font-size:18px}.row-menu{z-index:20;background:var(--color-surface);border:1px solid var(--color-border);text-align:left;border-radius:8px;flex-direction:column;gap:6px;min-width:200px;padding:8px;display:flex;position:absolute;top:100%;right:0;box-shadow:0 4px 16px #0000001a}.row-menu button{color:var(--color-text);text-align:left;background:0 0;border-radius:6px;padding:6px 8px;font-size:13px;font-weight:500}.row-menu button:hover{background:var(--color-bg)}.row-menu-danger{color:var(--color-danger)!important}.row-menu-move{gap:6px;padding:4px 0;display:flex}.row-menu-move select{padding:4px 6px;font-size:12px}.row-menu-move button{white-space:nowrap;background:var(--color-primary)!important;color:#fff!important}.teacher-groups-header{justify-content:space-between;align-items:center;gap:16px;margin-bottom:4px;display:flex}.teacher-groups-header h1{margin:0}.group-form-page{max-width:480px}.group-form{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;flex-direction:column;gap:14px;margin-top:16px;padding:24px;display:flex}.group-form label{color:var(--color-muted);flex-direction:column;gap:6px;font-size:13px;font-weight:600;display:flex}.student-username{color:var(--color-muted);margin-top:-8px}.student-detail-grid{grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:16px;margin-top:16px;display:grid}.student-panel{background:var(--color-surface);border:1px solid var(--color-border);border-radius:10px;padding:18px 20px}.student-panel h3{margin-top:0}.plain-list{flex-direction:column;gap:6px;margin:0;padding:0;font-size:14px;list-style:none;display:flex}.student-edit-form{flex-direction:column;gap:10px;display:flex}.student-edit-form label{color:var(--color-muted);flex-direction:column;gap:4px;font-size:12px;font-weight:600;display:flex}.student-edit-form button{align-self:flex-start}