/* ─── RESET & BASE ─────────────────────────────── */
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:system-ui,-apple-system,sans-serif;font-size:14px;background:#f5f6fa;color:#1a1a2e}
button{cursor:pointer;font-family:inherit;font-size:13px}
input,select,textarea{font-family:inherit;font-size:13px;color:#1a1a2e}

/* ─── LAYOUT ───────────────────────────────────── */
.shell{display:flex;min-height:100vh}
/* In combined mode (admin overview), STAS shares the page — no forced full height */
#educait-timetable-root:not([style*="flex:1"]) .shell{min-height:0;}
.sidebar{width:210px;background:#1a1a2e;flex-shrink:0;display:flex;flex-direction:column;padding:0 0 1rem}
.sidebar-logo{padding:1.25rem 1.25rem 1rem;border-bottom:1px solid rgba(255,255,255,.1);margin-bottom:.5rem}
.sidebar-logo h1{font-size:14px;font-weight:600;color:#fff;line-height:1.4}
.sidebar-logo p{font-size:11px;color:rgba(255,255,255,.45);margin-top:2px}
.nav-item{display:flex;align-items:center;gap:9px;padding:9px 1.25rem;font-size:13px;color:rgba(255,255,255,.6);border:none;background:transparent;width:100%;text-align:left;border-left:3px solid transparent;transition:all .15s;position:relative}
.nav-item:hover{color:#fff;background:rgba(255,255,255,.07)}
.nav-item.active{color:#fff;background:rgba(255,255,255,.12);border-left-color:#6c9fff}
.nav-item .nav-icon{font-size:16px;width:20px;text-align:center}
.nav-badge{background:#e74c3c;color:#fff;border-radius:10px;padding:1px 6px;font-size:10px;margin-left:auto}
.main{flex:1;overflow:auto;padding:1.75rem 2rem;background:#f5f6fa}
.page-header{margin-bottom:1.5rem}
.page-header h2{font-size:20px;font-weight:600;color:#1a1a2e}
.page-header p{font-size:13px;color:#666;margin-top:3px}

/* ─── COMPONENTS ───────────────────────────────── */
.btn{display:inline-flex;align-items:center;gap:5px;padding:7px 14px;border-radius:8px;border:1px solid;font-weight:500;transition:all .12s;font-size:13px}
.btn-primary{background:#3b5bdb;border-color:#3b5bdb;color:#fff}
.btn-primary:hover{background:#2f4ac7}
.btn-secondary{background:#fff;border-color:#ddd;color:#444}
.btn-secondary:hover{background:#f5f6fa}
.btn-danger{background:#fff5f5;border-color:#fcc;color:#c0392b}
.btn-danger:hover{background:#ffe0e0}
.btn-success{background:#ebfbee;border-color:#b2f2c1;color:#2f7a3e}
.btn-success:hover{background:#d3f9df}
.btn-lg{padding:10px 20px;font-size:14px}
.btn-sm{padding:4px 9px;font-size:11px;border-radius:6px}
.btn:disabled{opacity:.45;cursor:not-allowed}

.card{background:#fff;border-radius:12px;border:1px solid #e8eaf0;padding:1.25rem}
.card+.card{margin-top:1rem}

.badge{display:inline-flex;align-items:center;padding:2px 8px;border-radius:20px;font-size:11px;font-weight:500;border:1px solid}
.badge-ps{background:#e8f4fd;border-color:#3498db;color:#1a6fa8}
.badge-ms{background:#eafaf1;border-color:#27ae60;color:#1a6f3c}
.badge-hs{background:#f3e5f5;border-color:#8e24aa;color:#6a1b9a}
.badge-subject{background:#f0edff;border-color:#9b8ff5;color:#5842c3}
.badge-class{background:#e8fdf5;border-color:#48c9b0;color:#0e7c65}
.badge-warn{background:#fff3cd;border-color:#f0a500;color:#7d5a00}

.form-group{margin-bottom:1rem}
.form-label{display:block;font-size:12px;font-weight:600;color:#555;margin-bottom:5px;text-transform:uppercase;letter-spacing:.04em}
.form-control{width:100%;padding:8px 10px;border:1px solid #ddd;border-radius:8px;background:#fff;transition:border-color .12s}
.form-control:focus{outline:none;border-color:#3b5bdb;box-shadow:0 0 0 3px rgba(59,91,219,.12)}
.form-row{display:grid;gap:12px}
.form-row-2{grid-template-columns:1fr 1fr}
.form-row-3{grid-template-columns:1fr 1fr 1fr}

.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.45);display:flex;align-items:center;justify-content:center;z-index:1000;padding:1rem}
.modal-box{background:#fff;border-radius:14px;padding:1.5rem;width:100%;max-width:560px;max-height:90vh;overflow-y:auto;box-shadow:0 20px 60px rgba(0,0,0,.2)}
.modal-box.modal-lg{max-width:700px}
.modal-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:1.25rem}
.modal-header h3{font-size:16px;font-weight:600}
.modal-close{background:transparent;border:none;font-size:20px;color:#999;padding:0;line-height:1}
.modal-footer{display:flex;gap:8px;justify-content:flex-end;margin-top:1.25rem;padding-top:1rem;border-top:1px solid #f0f0f0}

.tag-input-wrap{display:flex;flex-wrap:wrap;gap:5px;padding:6px 8px;border:1px solid #ddd;border-radius:8px;background:#fff;min-height:38px;align-items:center;cursor:text}
.tag-input-wrap:focus-within{border-color:#3b5bdb;box-shadow:0 0 0 3px rgba(59,91,219,.12)}
.tag-input-wrap input{border:none;outline:none;background:transparent;flex:1;min-width:80px;font-size:13px}
.tag-chip{font-size:11px;padding:2px 5px 2px 8px;border-radius:20px;background:#f0edff;border:1px solid #c4b9ff;color:#5842c3;display:flex;align-items:center;gap:3px}
.tag-chip button{background:transparent;border:none;cursor:pointer;font-size:12px;color:#9b8ff5;line-height:1;padding:0}

.divider{border:none;border-top:1px solid #eee;margin:1rem 0}

.empty-state{text-align:center;padding:3rem 1rem;color:#aaa}
.empty-state .empty-icon{font-size:40px;display:block;margin-bottom:.75rem}
.empty-state p{font-size:13px}

.alert{padding:10px 14px;border-radius:8px;font-size:13px;display:flex;align-items:flex-start;gap:8px;margin-bottom:1rem}
.alert-warning{background:#fff8e6;border:1px solid #f0c04a;color:#7a5800}
.alert-error{background:#fff5f5;border:1px solid #fcc;color:#c0392b}
.alert-success{background:#ebfbee;border:1px solid #b2f2c1;color:#2f7a3e}
.alert-info{background:#e8f4fd;border:1px solid #aad4f5;color:#1a6fa8}

/* ─── TEACHER CARDS ────────────────────────────── */
.teacher-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:12px}
.teacher-card{background:#fff;border:1px solid #e8eaf0;border-radius:12px;padding:1rem}
.teacher-card-top{display:flex;align-items:center;gap:10px;margin-bottom:.75rem}
.avatar{width:38px;height:38px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:600;flex-shrink:0}
.teacher-name{font-weight:600;font-size:14px}
.teacher-meta{font-size:12px;color:#888}
.subject-assignment{background:#fafafa;border:1px solid #eee;border-radius:8px;padding:8px 10px;margin-bottom:6px}
.subject-assignment-name{font-weight:500;font-size:13px;color:#333;margin-bottom:5px;display:flex;align-items:center;gap:6px}
.class-tags{display:flex;flex-wrap:wrap;gap:4px}

/* ─── CLASSES TAB ──────────────────────────────── */
.class-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:12px}
.class-card{background:#fff;border:1px solid #e8eaf0;border-radius:12px;padding:1rem}
.class-card.expanded{grid-column:1/-1;border-color:#c5cff5}
.class-code-big{font-size:24px;font-weight:700;letter-spacing:-.03em;color:#1a1a2e}
.class-detail{font-size:12px;color:#888;margin-bottom:.75rem}
.subject-row{display:flex;align-items:center;gap:8px;padding:6px 0;border-bottom:1px solid #f5f5f5}
.subject-row:last-child{border-bottom:none}
.subject-check{display:flex;align-items:center;gap:6px;min-width:140px;font-size:12px;font-weight:500}
.subject-check input[type=checkbox]{width:14px;height:14px;accent-color:#3b5bdb;cursor:pointer}
.subject-teacher-sel{flex:1;padding:4px 7px;border:1px solid #ddd;border-radius:6px;font-size:12px;background:#fff;min-width:0}
.subject-freq-inp{width:52px;padding:4px 6px;border:1px solid #ddd;border-radius:6px;font-size:12px;text-align:center}
.freq-label{font-size:11px;color:#888;white-space:nowrap}
.subj-panel-row{display:grid;grid-template-columns:170px 1fr 70px auto auto;align-items:start;gap:8px;padding:8px 10px;border-radius:8px;margin-bottom:4px}
.subj-panel-row.enabled{background:#f8f9ff;border:1px solid #e8eaff}
.subj-panel-row.disabled{background:#fafafa;border:1px solid transparent;opacity:.65}
.subj-name-cell{display:flex;align-items:center;gap:7px;font-size:12px;font-weight:500;padding-top:3px}
.subj-freq-cell{display:flex;align-items:center;gap:5px;white-space:nowrap;padding-top:3px}
.subj-opt-cell{display:flex;flex-direction:column;gap:5px;padding-top:2px}
.alt-row{display:flex;flex-direction:column;gap:4px;padding:6px 8px;background:#fff8e6;border:1px solid #f0c04a;border-radius:6px;font-size:11px;margin-top:4px}
.alt-row label{display:flex;align-items:center;gap:5px;cursor:pointer;font-weight:500;color:#7a5800}
.dbl-lbl{display:flex;align-items:center;gap:5px;cursor:pointer;font-size:11px;font-weight:500;color:#555;white-space:nowrap}
.badge-alt{background:#fff3cd;border-color:#f0c04a;color:#7d5a00}
.badge-dbl{background:#e8f4fd;border-color:#3498db;color:#1a6fa8}

/* ─── TIMETABLE GRID ───────────────────────────── */
.tt-outer{overflow-x:auto;border-radius:10px;border:1px solid #e8eaf0}
.tt-table{border-collapse:collapse;width:100%;background:#fff;font-size:12px;min-width:700px}
.tt-table th{padding:8px 10px;font-size:11px;font-weight:600;color:#666;text-align:left;background:#f8f9fc;border-bottom:1px solid #e8eaf0;white-space:nowrap;position:sticky;top:0;z-index:2}
.tt-table th.row-hd-th{position:sticky;left:0;z-index:3;background:#f8f9fc}
.tt-table td{padding:3px;border:1px solid #f0f2f8;vertical-align:top;min-width:100px}
.tt-table td.row-hd{padding:8px 12px;font-weight:600;font-size:12px;background:#fafbff;white-space:nowrap;min-width:130px;position:sticky;left:0;z-index:1;border-right:2px solid #e8eaf0}
.tt-table tr:hover td{background:#fafbff}
.tt-table tr:hover td.row-hd{background:#f3f4fa}
.cell-empty{min-height:54px;border-radius:7px;border:1.5px dashed #e0e4f0;cursor:pointer;display:flex;align-items:center;justify-content:center;color:#bbb;font-size:11px;transition:all .12s}
.cell-empty:hover{border-color:#3b5bdb;color:#3b5bdb;background:#f0f4ff}
.cell-break{min-height:54px;background:#fffbf0;border-radius:7px;display:flex;flex-direction:column;align-items:center;justify-content:center;font-size:10px;color:#d4881a;font-weight:600;gap:2px;border:1px solid #ffe5a0}
.cell-lunch{min-height:54px;background:#fff5f5;border-radius:7px;display:flex;flex-direction:column;align-items:center;justify-content:center;font-size:10px;color:#c0392b;font-weight:600;gap:2px;border:1px solid #fcc;opacity:.8}
.cell-lesson{min-height:54px;border-radius:7px;padding:6px 8px;font-size:11px;display:flex;flex-direction:column;gap:2px;cursor:pointer;transition:filter .1s;position:relative}
.cell-lesson:hover{filter:brightness(.95)}
.cell-lesson.conflict{outline:2px solid #e74c3c;outline-offset:-2px}
.lesson-sub{font-weight:600;color:#1a1a2e;font-size:11.5px;line-height:1.3}
.lesson-sec{color:#666;font-size:10px}
.lesson-rm{background:transparent;border:none;font-size:10px;color:#e74c3c;padding:0;margin-top:auto;text-align:left;cursor:pointer;display:none}
.cell-lesson:hover .lesson-rm{display:block}
.period-col-head{display:flex;flex-direction:column;gap:1px}
.period-col-head span:first-child{font-weight:600;color:#444}
.period-col-head span:last-child{font-weight:400;color:#aaa;font-size:10px}

/* ─── OVERVIEW ─────────────────────────────────── */
.overview-stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(130px,1fr));gap:12px;margin-bottom:1.5rem}
.stat-box{background:#fff;border:1px solid #e8eaf0;border-radius:10px;padding:1rem 1.25rem}
.stat-val{font-size:28px;font-weight:700;color:#1a1a2e;line-height:1}
.stat-lbl{font-size:11px;color:#888;margin-top:4px;text-transform:uppercase;letter-spacing:.04em}
.autosched-card{background:linear-gradient(135deg,#3b5bdb,#6c9fff);border-radius:12px;padding:1.5rem;color:#fff;margin-bottom:1.5rem;display:flex;align-items:center;justify-content:space-between;gap:1rem;flex-wrap:wrap}
.autosched-card h3{font-size:16px;font-weight:700;margin-bottom:4px}
.autosched-card p{font-size:13px;opacity:.85}
.export-card{background:#fff;border:1px solid #e8eaf0;border-radius:12px;padding:1.25rem;margin-bottom:1rem}
.export-card h4{font-size:14px;font-weight:600;margin-bottom:.5rem;display:flex;align-items:center;gap:7px}
.export-card p{font-size:12px;color:#666;margin-bottom:1rem}
.export-btn-row{display:flex;gap:8px;flex-wrap:wrap}

/* ─── SCHEDULE DETAIL ──────────────────────────── */
.sched-nav{display:flex;gap:6px;margin-bottom:1rem;flex-wrap:wrap}
.sched-tab{padding:6px 13px;border-radius:8px;border:1px solid #ddd;background:#fff;font-size:12px;color:#555;transition:all .12s}
.sched-tab.active{background:#3b5bdb;border-color:#3b5bdb;color:#fff;font-weight:600}
.day-period-row{display:grid;grid-template-columns:90px 1fr;gap:8px;margin-bottom:4px;min-height:52px;align-items:stretch}
.dpr-time{display:flex;flex-direction:column;justify-content:center;text-align:right;padding-right:10px;border-right:2px solid #eee}
.dpr-t1{font-size:12px;font-weight:600;color:#333}
.dpr-t2{font-size:10px;color:#aaa}
.dpr-cell-lesson{background:#eef2ff;border:1px solid #c5cff5;border-radius:8px;padding:9px 12px;display:flex;flex-direction:column;gap:3px}
.dpr-cell-empty{background:#fafafa;border:1px dashed #ddd;border-radius:8px;padding:9px 12px;color:#bbb;font-size:12px;display:flex;align-items:center}
.dpr-cell-break{background:#fffbf0;border:1px solid #ffe5a0;border-radius:8px;padding:9px 12px;display:flex;align-items:center;color:#d4881a;font-size:12px;font-weight:500}
.dpr-cell-lunch{background:#fff5f5;border:1px solid #fcc;border-radius:8px;padding:9px 12px;display:flex;align-items:center;color:#c0392b;font-size:12px;font-weight:500}
.dpr-cell-conflict{background:#fff5f5;border:2px solid #e74c3c;border-radius:8px;padding:9px 12px;display:flex;flex-direction:column;gap:3px}

/* ─── CONFLICTS ────────────────────────────────── */
.conflict-item{background:#fff5f5;border:1px solid #fcc;border-radius:8px;padding:10px 14px;display:flex;gap:10px;margin-bottom:8px}
.conflict-icon{font-size:18px;color:#e74c3c;flex-shrink:0}
.conflict-title{font-size:13px;font-weight:600;color:#c0392b}
.conflict-desc{font-size:12px;color:#666;margin-top:2px}
.conflict-link{font-size:11px;color:#3b5bdb;text-decoration:underline;cursor:pointer;margin-top:4px;display:inline-block}

/* ─── PROGRESS ─────────────────────────────────── */
.progress-overlay{position:fixed;inset:0;background:rgba(26,26,46,.7);display:flex;align-items:center;justify-content:center;z-index:2000}
.progress-box{background:#fff;border-radius:14px;padding:2rem;text-align:center;min-width:260px}
.progress-box h3{font-size:16px;font-weight:600;margin-bottom:.5rem}
.progress-box p{font-size:13px;color:#666;margin-bottom:1rem}
.spinner{width:36px;height:36px;border:3px solid #e8eaf0;border-top-color:#3b5bdb;border-radius:50%;animation:spin .8s linear infinite;margin:0 auto 1rem}
@keyframes spin{to{transform:rotate(360deg)}}

/* ─── MISC ─────────────────────────────────────── */
.toolbar{display:flex;align-items:center;gap:8px;margin-bottom:1rem;flex-wrap:wrap}
.toolbar-right{margin-left:auto;display:flex;gap:6px;align-items:center}
.section-title{font-size:13px;font-weight:700;color:#444;text-transform:uppercase;letter-spacing:.05em;margin-bottom:.75rem;display:flex;align-items:center;gap:7px}
.section-title::after{content:"";flex:1;height:1px;background:#eee}
.subject-group{background:#fff;border:1px solid #e8eaf0;border-radius:10px;overflow:hidden;margin-bottom:12px}
.subject-group-header{padding:10px 14px;background:#f8f9fc;font-size:12px;font-weight:700;color:#555;text-transform:uppercase;letter-spacing:.05em;border-bottom:1px solid #e8eaf0}
.subject-group-body{padding:4px 14px}

/* ─── LANGUAGE TOGGLE ──────────────────────────────── */
.lang-toggle{display:flex;align-items:center;gap:8px;padding:5px 14px;border-radius:20px;
  cursor:pointer;font-size:12px;font-weight:600;transition:all .2s;border:2px solid #ddd;
  background:#fff;color:#444}
.lang-toggle.zh{background:#1a1a2e;border-color:#3b5bdb;color:#fff}

/* ── Embedded mode (inside EduCAIT dashboard — sidebar/header suppressed) ── */
.educait-embedded{min-height:0!important;width:100%;height:100%;}
.educait-embedded .main{min-height:600px;padding:1.25rem 1.5rem;}

@media(max-width:700px){
  .shell{flex-direction:column}
  .sidebar{width:100%;padding:.5rem 0}
  .main{padding:1rem}
}

/* ─── DRAG & DROP TIMETABLE ────────────────────────────── */
.cell-lesson[draggable]{cursor:grab}
.cell-lesson[draggable]:active{cursor:grabbing}
.cell-lesson.dragging{opacity:.35;outline:2px dashed #3b5bdb}
.cell-drop-target{background:#eef6ff!important;border:2px dashed #3b5bdb!important;cursor:pointer}
.cell-drop-target:hover{background:#ddeeff!important}
.cell-free-clickable{cursor:pointer;min-height:54px;display:flex;align-items:center;justify-content:center;
  color:#bbb;font-size:11px;border-radius:8px;border:2px dashed transparent;transition:all .15s}
.cell-free-clickable:hover{background:#eef6ff;border-color:#3b5bdb;color:#3b5bdb}
.cell-free-clickable:hover::before{content:"+ Assign"}
.assign-modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.45);z-index:4000;display:flex;align-items:center;justify-content:center}
.assign-modal{background:#fff;border-radius:14px;padding:1.5rem;min-width:340px;max-width:460px;box-shadow:0 20px 60px rgba(0,0,0,.25);max-height:80vh;overflow-y:auto}
.assign-modal h3{font-size:15px;font-weight:700;margin-bottom:.25rem;color:#1a1a2e}
.assign-modal .slot-label{font-size:11px;color:#888;margin-bottom:1rem}
.assign-modal select{width:100%;padding:8px 10px;border:1px solid #ddd;border-radius:8px;font-size:13px;margin-bottom:.75rem}
.assign-modal .btn-row{display:flex;gap:8px;justify-content:flex-end}
.conflict-tooltip{position:absolute;bottom:calc(100% + 6px);left:50%;transform:translateX(-50%);background:#c0392b;
  color:#fff;font-size:10px;padding:4px 8px;border-radius:5px;white-space:nowrap;z-index:100;
  pointer-events:none;box-shadow:0 2px 8px rgba(0,0,0,.25)}
.conflict-tooltip::after{content:"";position:absolute;top:100%;left:50%;transform:translateX(-50%);
  border:4px solid transparent;border-top-color:#c0392b}
.cell-wrap{position:relative}