:root{--bg: #f5f7fb;--panel: #ffffff;--line: #d9e0ea;--text: #172033;--muted: #657386;--accent: #2563eb;--accent-soft: #eaf1ff;--danger: #b42318}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}button,input,select{font:inherit}button{border:0;border-radius:7px;background:var(--accent);color:#fff;min-height:38px;padding:0 12px;cursor:pointer}button:disabled{cursor:not-allowed;opacity:.55}input,select{width:100%;border:1px solid var(--line);border-radius:7px;padding:9px 10px;background:#fff;color:var(--text)}.login-page{min-height:100vh;display:grid;place-items:center;padding:18px}.login-card{width:min(420px,100%);display:grid;gap:12px;padding:24px;background:var(--panel);border:1px solid var(--line);border-radius:8px;box-shadow:0 18px 50px #1c274214}.login-card h1,.page-head h1,.teacher h1{margin:0;font-size:28px}.login-card p,.page-head p,.teacher p,.hint{margin:0;color:var(--muted)}.login-card label{display:grid;gap:6px;color:var(--muted)}.error{color:var(--danger)}.shell{min-height:100vh;display:grid;grid-template-columns:232px 1fr}.sidebar{position:sticky;top:0;height:100vh;display:flex;flex-direction:column;gap:6px;padding:16px 12px;border-right:1px solid var(--line);background:#fff}.brand{font-weight:800;font-size:22px;margin:4px 8px 16px}.sidebar button{justify-content:flex-start;display:flex;align-items:center;gap:10px;background:transparent;color:var(--text)}.sidebar button.active{background:var(--accent-soft);color:var(--accent)}.content{min-width:0;padding:20px}.page-head{margin-bottom:16px}.metric-grid{display:grid;grid-template-columns:repeat(4,minmax(160px,1fr));gap:10px;margin-bottom:12px}.metric-grid.small{grid-template-columns:repeat(3,1fr)}.metric{background:var(--panel);border:1px solid var(--line);border-radius:8px;padding:12px}.metric span{display:block;color:var(--muted);font-size:13px}.metric strong{display:block;margin-top:5px;font-size:22px}.panel{background:var(--panel);border:1px solid var(--line);border-radius:8px;padding:14px;overflow:hidden}.panel h2{margin:0 0 12px;font-size:18px}.panel h3{margin:16px 0 8px}.panel input,.panel select{margin-bottom:9px}.wide{grid-column:1 / -1}.chart-panel{margin-bottom:12px}.toolbar{display:flex;align-items:center;gap:8px;margin:10px 0}.toolbar input,.toolbar select{max-width:320px}.two-col{display:grid;grid-template-columns:minmax(280px,360px) 1fr;gap:12px}.table-wrap{overflow:auto;max-height:55vh;border:1px solid var(--line);border-radius:8px;background:#fff}.data-table{width:100%;border-collapse:separate;border-spacing:0;font-size:14px}.data-table th,.data-table td{text-align:left;white-space:nowrap;border-bottom:1px solid var(--line);padding:9px 10px}.data-table th{position:sticky;top:0;z-index:1;background:#f9fbfe;color:#4b5870;font-weight:700}.data-table tr:hover td{background:#f8fbff}.cell-input{width:92px;min-width:92px;padding:5px 6px;margin:0}.debt{color:var(--danger);font-weight:700}.report-grid{display:grid;gap:12px}.download{display:block;width:100%;margin-bottom:8px;text-align:left;background:#eef2f7;color:var(--text)}.danger-btn{background:#fee4e2;color:var(--danger)}.undo-btn{margin-top:8px;background:#ecfdf3;color:#027a48}.row-check{width:18px;height:18px;margin:0}.schedule-box{margin-top:18px;padding-top:12px;border-top:1px solid var(--line)}.edit-box{margin:14px 0;padding:12px;border:1px solid var(--line);border-radius:8px;background:#fbfcfe}.course-line{display:grid;gap:4px;padding:10px 0;border-bottom:1px solid var(--line)}.course-line span{color:var(--muted)}.schedule-row{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:8px 0;border-bottom:1px solid var(--line)}.schedule-row button{min-height:30px;background:#eef2f7;color:var(--text)}.teacher{width:min(720px,100%);margin:0 auto;padding:14px}.teacher header{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}.lesson-list{display:grid;gap:10px}.lesson-list button{display:grid;justify-items:start;gap:4px;min-height:72px;background:#fff;border:1px solid var(--line);color:var(--text)}.lesson-list span{color:var(--muted)}.back{background:#eef2f7;color:var(--text)}.summary{margin:12px 0;padding:10px;background:var(--accent-soft);border-radius:8px;color:var(--accent);font-weight:700}.attendance-row{display:grid;gap:10px;padding:14px 0;border-bottom:1px solid var(--line)}.attendance-row div{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}.attendance-row button{background:#eef2f7;color:var(--text);min-height:44px}.attendance-row button.selected{background:var(--accent);color:#fff}.save{width:100%;margin-top:14px;min-height:48px}@media (max-width: 860px){.shell{grid-template-columns:1fr}.sidebar{position:static;height:auto;flex-direction:row;overflow-x:auto}.brand{display:none}.content{padding:12px}.metric-grid,.metric-grid.small,.two-col{grid-template-columns:1fr}}