:root {
  --navy: #17324d;
  --ink: #1f2d3d;
  --muted: #6e7d8d;
  --line: #dfe6ec;
  --paper: #f6f8fa;
  --white: #ffffff;
  --blue: #2e6f9f;
  --blue-soft: #e9f2f8;
  --teal: #3d8b8b;
  --orange: #c47737;
  --danger: #b34d4d;
  font-family: Inter, "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  color: var(--ink);
  background: var(--paper);
}
* { box-sizing: border-box; }
body { margin: 0; min-width: 0; background: var(--paper); }
button, select, input { font: inherit; }
button { cursor: pointer; }
.app-shell { min-height: 100vh; display: flex; }
.sidebar { width: 310px; flex: 0 0 310px; background: var(--navy); color: #f4f8fb; padding: 28px 20px 22px; display: flex; flex-direction: column; overflow-y: auto; }
.brand { display: flex; gap: 12px; align-items: center; padding: 0 8px 30px; border-bottom: 1px solid rgba(255,255,255,.15); }
.brand-mark { width: 34px; height: 34px; display: grid; place-items: center; border: 1px solid #8eafc7; color: #dceaf3; font-weight: 700; font-size: 18px; }
.brand-title { font-size: 15px; font-weight: 700; letter-spacing: .2px; }
.brand-subtitle { margin-top: 3px; color: #9db4c8; font-size: 11px; }
.sidebar-section { padding: 25px 8px 0; }
.section-label { color: #b9d1df; text-transform: uppercase; font-size: 12px; letter-spacing: 1px; font-weight: 800; margin-bottom: 12px; }
.selected-courses { display: grid; gap: 8px; margin-bottom: 12px; }
.replacement-history { display: grid; gap: 5px; margin-top: 15px; }
.original-plan-courses { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 7px; max-height: 48vh; overflow: auto; padding: 2px; }
.original-plan-option { display: flex; align-items: center; gap: 8px; padding: 9px 10px; border: 1px solid var(--line); background: #fbfcfd; color: var(--ink); font-size: 11px; cursor: pointer; }
.original-plan-option:hover { border-color: #a9c4d4; background: var(--blue-soft); }
.original-plan-option input { accent-color: var(--blue); }
.history-label { color: #9db4c8; font-size: 10px; font-weight: 700; letter-spacing: 1px; text-transform: uppercase; }
.history-item { color: #c7d7e2; font-size: 10px; line-height: 1.4; overflow-wrap: anywhere; }
.course-chip { display: flex; align-items: center; justify-content: space-between; background: rgba(255,255,255,.08); border-left: 3px solid #9bc1d7; padding: 10px 10px 10px 12px; font-size: 13px; }
.course-chip span { color: #b9cddd; font-size: 11px; display: block; margin-top: 3px; }
.course-instructor { color: #d8e7ef; display: block; font-size: 9px; margin-top: 3px; }
.course-chip-actions { display: flex; align-items: center; gap: 4px; }
.course-info-button { border: 1px solid rgba(255,255,255,.22); border-radius: 50%; background: transparent; color: #c7d7e2; cursor: pointer; font-size: 10px; width: 18px; height: 18px; padding: 0; }
.course-info-button:hover { background: rgba(255,255,255,.12); color: #fff; }
.remove-course { background: transparent; color: #a9c0d0; border: 0; font-size: 18px; line-height: 1; padding: 0 2px; }
.secondary-button, .primary-button, .icon-button, .upload-button { border: 0; font-weight: 650; transition: .18s ease; }
.secondary-button { background: #edf3f7; color: var(--navy); padding: 10px 13px; border-radius: 3px; }
.secondary-button:hover { background: #dce9f1; }
.full-width { width: 100%; text-align: left; }
.upload-button { display: block; text-align: center; padding: 10px 12px; border: 1px solid rgba(255,255,255,.25); color: #eaf3f8; font-size: 12px; border-radius: 3px; }
.upload-button:hover { background: rgba(255,255,255,.08); }
.helper-text { color: #8fa8ba; font-size: 10px; line-height: 1.5; padding-top: 9px; }
.course-overview-section { padding-top: 20px; }
.master-pdf-links { display: grid; gap: 6px; margin-bottom: 12px; }
.master-pdf-links a { color: #eaf3f8; font-size: 10px; line-height: 1.4; text-decoration: underline; text-underline-offset: 3px; }
.master-pdf-links a + a { color: #9db4c8; text-decoration: none; }
.catalog-search { display: flex; align-items: center; gap: 7px; padding: 8px 9px; border-radius: 18px; background: rgba(255,255,255,.12); color: #c7d7e2; }
.catalog-search input { width: 100%; border: 0; outline: 0; background: transparent; color: #f4f8fb; font-size: 12px; }
.catalog-search input::placeholder { color: #9db4c8; }
.course-catalog { display: grid; gap: 5px; margin-top: 12px; max-height: 380px; overflow: auto; padding-right: 3px; }
.catalog-group { border-bottom: 1px solid rgba(255,255,255,.08); }
.catalog-course-button { display: grid; grid-template-columns: 16px 1fr auto; align-items: center; gap: 4px; width: 100%; padding: 8px 3px; border: 0; border-left: 3px solid var(--course-color); background: transparent; color: #f4f8fb; text-align: left; }
.catalog-course-button:hover, .catalog-group.is-open .catalog-course-button { background: rgba(255,255,255,.08); }
.catalog-course-button strong { color: var(--course-color); font-size: 14px; font-weight: 850; }
.catalog-course-button small { color: #9db4c8; font-size: 9px; }
.catalog-chevron { color: #d8e7ef; font-size: 17px; line-height: 1; }
.catalog-class-list { display: grid; gap: 4px; padding: 3px 0 7px 18px; }
.catalog-class { display: flex; align-items: center; justify-content: space-between; gap: 5px; padding: 7px 6px; background: rgba(255,255,255,.06); border-left: 2px solid var(--course-color); }
.catalog-class strong { color: #f4f8fb; font-size: 12px; font-weight: 800; }
.catalog-class span { display: block; max-width: 165px; margin-top: 3px; color: #b9cddd; font-size: 8px; line-height: 1.4; }
.catalog-add-button { flex: 0 0 auto; padding: 4px 6px; border: 1px solid rgba(255,255,255,.25); border-radius: 2px; background: transparent; color: #eaf3f8; font-size: 9px; }
.catalog-add-button:hover, .catalog-add-button.added { background: #eaf3f8; color: var(--navy); }
.saved-section { padding-top: 22px; }
.saved-plans { display: grid; gap: 8px; }
.saved-empty { color: #8fa8ba; font-size: 10px; line-height: 1.45; }
.saved-plan { background: rgba(255,255,255,.08); border-left: 3px solid #d89a5f; padding: 10px 10px 9px 12px; }
.saved-plan.original-plan { border-left-color: #9bc1d7; }
.saved-plan.original-plan .saved-plan-name { color: #e05252; font-weight: 850; }
.saved-plan-name { color: #f4f8fb; font-size: 14px; font-weight: 700; line-height: 1.3; overflow-wrap: anywhere; }
.saved-plan-route { color: #b9cddd; font-size: 10px; line-height: 1.4; margin-top: 5px; }
.saved-plan-history { color: #9db4c8; font-size: 8px; line-height: 1.35; margin-top: 4px; }
.saved-plan-actions { display: flex; gap: 6px; margin-top: 8px; }
.saved-plan-actions button { background: transparent; border: 1px solid rgba(255,255,255,.22); color: #c7d7e2; padding: 4px 7px; font-size: 10px; border-radius: 2px; }
.saved-plan-actions button:hover { background: rgba(255,255,255,.1); color: #fff; }
.plan-info-courses { display: grid; gap: 8px; max-height: 48vh; overflow: auto; }
.plan-info-course { display: grid; gap: 3px; border: 1px solid var(--line); background: #fbfcfd; color: var(--ink); padding: 9px 10px; }
.plan-info-course strong { font-size: 11px; }
.plan-info-course span, .plan-info-course small { color: var(--muted); font-size: 9px; line-height: 1.35; }
.plan-info-course .course-instructor { color: var(--blue); font-size: 9px; }
.plan-notes-label { display: grid; gap: 6px; margin-top: 12px; color: var(--ink); font-size: 11px; }
.plan-notes-label textarea { width: 100%; resize: vertical; border: 1px solid var(--line); background: #fbfcfd; color: var(--ink); padding: 8px 9px; font: inherit; font-size: 10px; line-height: 1.45; box-sizing: border-box; }
.plan-history-editor { margin-top: 14px; }
.plan-history-title { color: var(--ink); font-size: 11px; margin-bottom: 7px; }
.plan-history-row { display: grid; grid-template-columns: minmax(0,1fr) auto minmax(0,1fr) auto; align-items: center; gap: 5px; margin-bottom: 6px; }
.plan-history-row select { min-width: 0; border: 1px solid var(--line); background: #fbfcfd; color: var(--ink); padding: 5px 6px; font-size: 9px; }
.plan-history-row span { color: var(--muted); font-size: 9px; }
.history-delete { border: 0; background: transparent; color: #b76060; cursor: pointer; font-size: 14px; line-height: 1; padding: 2px 4px; }
.history-delete:hover { color: #8d2f2f; }
.sidebar-footer { margin-top: auto; border-top: 1px solid rgba(255,255,255,.15); padding: 18px 8px 0; display: grid; gap: 9px; color: #adbfcd; font-size: 11px; }
.legend-row { display: flex; align-items: center; gap: 8px; }
.legend-dot { width: 8px; height: 8px; border-radius: 50%; background: #9bc1d7; }.legend-dot.alternative { background: #d89a5f; }.legend-dot.muted { background: #788e9d; }
.main-content { flex: 1; padding: 42px 46px 54px; max-width: 1500px; }
.topbar { display: flex; justify-content: space-between; gap: 30px; align-items: flex-start; margin-bottom: 28px; }
.eyebrow { color: var(--blue); font-size: 10px; font-weight: 750; letter-spacing: 1.7px; text-transform: uppercase; }
h1, h2, p { margin: 0; } h1 { color: var(--navy); font-size: 28px; line-height: 1.2; margin-top: 7px; letter-spacing: -.3px; } h2 { color: var(--navy); font-size: 17px; }
.subtitle { color: var(--muted); font-size: 13px; margin-top: 8px; }
.topbar-actions { display: flex; gap: 10px; padding-top: 10px; }
.user-bar { display: flex; align-items: center; gap: 7px; color: var(--navy); font-size: 11px; font-weight: 700; background: var(--white); border: 1px solid var(--line); padding: 5px 7px 5px 5px; height: 38px; }
.user-avatar { width: 25px; height: 25px; border-radius: 50%; background: var(--blue-soft); color: var(--blue); display: grid; place-items: center; font-size: 11px; font-weight: 800; }
.user-switch { border: 0; border-left: 1px solid var(--line); margin-left: 2px; padding: 3px 0 3px 8px; background: transparent; color: var(--blue); font-size: 10px; font-weight: 700; }
.user-switch:hover { color: var(--navy); }
.admin-button { color: #8b5a2b; }
.primary-button { background: var(--navy); color: #fff; padding: 11px 15px; border-radius: 3px; }.primary-button:hover { background: #285272; }
.icon-button { width: 38px; height: 38px; background: var(--white); color: var(--navy); border: 1px solid var(--line); border-radius: 3px; font-size: 19px; }.icon-button:hover { background: var(--blue-soft); }
.stats-row { display: grid; grid-template-columns: repeat(3, 1fr) 1.55fr; gap: 12px; margin-bottom: 23px; }
.stat-card, .status-card { min-height: 82px; background: var(--white); border: 1px solid var(--line); padding: 15px 17px; display: flex; align-items: baseline; gap: 8px; }.stat-card { position: relative; }.stat-label { color: var(--muted); font-size: 11px; position: absolute; top: 13px; left: 17px; }.stat-card strong { color: var(--navy); font-size: 28px; margin-top: 20px; }.stat-note { color: var(--muted); font-size: 11px; }
.status-card { align-items: center; gap: 11px; }.status-dot { width: 9px; height: 9px; border-radius: 50%; background: #8ba3b0; }.status-card strong, .status-card span { display: block; }.status-card strong { color: var(--navy); font-size: 12px; }.status-card span:last-child { color: var(--muted); font-size: 11px; margin-top: 4px; }
.workspace { background: var(--white); border: 1px solid var(--line); }.workspace-header { height: 67px; display: flex; align-items: center; justify-content: space-between; padding: 0 20px; border-bottom: 1px solid var(--line); }.muted-text, .view-caption { color: var(--muted); font-size: 11px; margin-top: 5px; }.view-caption { margin: 0; display: flex; align-items: center; gap: 7px; }.mini-dot { width: 7px; height: 7px; background: var(--blue); border-radius: 50%; }
.timetable { display: grid; grid-template-columns: 72px repeat(6, minmax(125px, 1fr)); position: relative; overflow: hidden; min-height: 806px; }.time-column, .day-column { position: relative; }.time-column { background: #fafbfc; border-right: 1px solid var(--line); }.day-header { height: 49px; border-bottom: 1px solid var(--line); padding: 16px 10px; text-align: center; color: var(--muted); font-size: 11px; font-weight: 700; }.day-header.active { color: var(--navy); background: var(--blue-soft); }.time-label { height: 108px; padding: 9px 9px; color: #8b99a6; font-size: 10px; border-bottom: 1px solid #edf1f4; text-align: right; }.day-body { height: 756px; position: relative; background-image: linear-gradient(to bottom, transparent 107px, #edf1f4 108px); background-size: 100% 108px; border-right: 1px solid var(--line); }.session { position: absolute; left: 7px; right: 7px; border-left: 4px solid var(--blue); background: #e6f0f6; padding: 11px 9px; overflow: hidden; min-height: 107px; color: var(--navy); }.session.teal { border-color: var(--teal); background: #e8f3f1; }.session.orange { border-color: var(--orange); background: #fbefe5; }.session.alternative { border-color: var(--orange); background: #fff5eb; box-shadow: inset 0 0 0 1px #e6b27c; }.session-code { font-size: 11px; font-weight: 800; white-space: nowrap; }.session-name { font-size: 10px; line-height: 1.35; margin-top: 7px; color: #456075; }.session-time { font-size: 10px; line-height: 1.35; margin-top: 7px; color: #6b7f8e; white-space: normal; overflow-wrap: anywhere; }.session-room { color: var(--navy); font-weight: 700; }.empty-state { grid-column: 2 / span 6; display: grid; place-items: center; min-height: 756px; color: var(--muted); font-size: 13px; background: repeating-linear-gradient(0deg, #fff, #fff 107px, #edf1f4 108px); }
.info-strip { display: flex; align-items: center; gap: 12px; padding: 15px 17px; margin-top: 14px; background: #edf4f7; border: 1px solid #d6e5ec; color: #416174; font-size: 11px; }.info-icon { width: 18px; height: 18px; border: 1px solid #7395a7; color: #52778c; border-radius: 50%; display: grid; place-items: center; font-family: Georgia, serif; font-weight: 700; }.info-strip strong { color: var(--navy); margin-right: 9px; }
.modal-backdrop { position: fixed; inset: 0; background: rgba(18,39,57,.38); display: grid; place-items: center; padding: 20px; z-index: 10; }.modal-backdrop[hidden] { display: none; }.modal { width: min(560px, 100%); background: #fff; padding: 26px; box-shadow: 0 18px 50px rgba(20,43,60,.25); }.modal-header { display: flex; justify-content: space-between; align-items: flex-start; }.modal h2 { font-size: 21px; margin-top: 6px; }.close-button { border: 0; background: transparent; color: var(--muted); font-size: 25px; line-height: 1; }.modal-copy { color: var(--muted); font-size: 12px; line-height: 1.6; margin: 17px 0 20px; }.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }.form-grid label { color: var(--muted); font-size: 11px; font-weight: 700; }.form-grid select { display: block; width: 100%; margin-top: 7px; padding: 10px; border: 1px solid var(--line); color: var(--ink); background: #fff; }.replacement-preview { margin-top: 17px; min-height: 58px; padding: 12px; background: #f7f9fa; border: 1px solid #e9eef1; color: var(--muted); font-size: 11px; line-height: 1.6; }.replacement-preview strong { color: var(--navy); }.modal-actions { display: flex; justify-content: flex-end; gap: 9px; margin-top: 20px; }
.toast { position: fixed; right: 28px; bottom: 25px; max-width: 390px; background: var(--navy); color: #fff; padding: 13px 16px; font-size: 12px; line-height: 1.55; box-shadow: 0 9px 24px rgba(23,50,77,.22); transform: translateY(18px); opacity: 0; pointer-events: none; transition: .2s ease; z-index: 20; }.toast.show { transform: translateY(0); opacity: 1; }.toast.error { background: #8e3f43; }
@media (max-width: 1180px) { .main-content { padding-left: 28px; padding-right: 28px; }.sidebar { width: 245px; flex-basis: 245px; } }
.form-grid input { display: block; width: 100%; margin-top: 7px; padding: 10px; border: 1px solid var(--line); color: var(--ink); background: #fff; }
.form-grid input:focus { border-color: var(--blue); box-shadow: 0 0 0 2px var(--blue-soft); outline: none; }
.plan-name-label { display: block; color: var(--muted); font-size: 11px; font-weight: 700; }
.plan-name-label input { display: block; width: 100%; margin-top: 7px; padding: 10px; border: 1px solid var(--line); color: var(--ink); background: #fff; }
.plan-name-label input:focus { border-color: var(--blue); box-shadow: 0 0 0 2px var(--blue-soft); outline: none; }
.plan-form-grid { margin-top: 16px; }
.login-backdrop { background: rgba(23,50,77,.72); }
.login-modal { width: min(430px, 100%); padding: 34px; }
.brand-login-mark { width: 42px; height: 42px; display: grid; place-items: center; border: 1px solid #8eafc7; color: var(--blue); font-weight: 800; font-size: 20px; margin-bottom: 22px; }
.login-modal h2 { font-size: 25px; margin-top: 7px; color: var(--navy); }
.login-note { margin-top: 13px; color: var(--muted); background: #f7f9fa; border: 1px solid #e9eef1; padding: 10px 12px; font-size: 10px; line-height: 1.5; }
.auth-mode-switch { display: flex; gap: 4px; margin: 0 0 18px; border-bottom: 1px solid var(--line); }
.auth-mode { border: 0; border-bottom: 2px solid transparent; background: transparent; color: var(--muted); padding: 8px 12px; font-size: 11px; font-weight: 700; }
.auth-mode.active { color: var(--navy); border-bottom-color: var(--blue); }
.auth-password-label { margin-top: 13px; }
.auth-password-label input { letter-spacing: .08em; }
.form-grid select[multiple] { min-height: 126px; padding: 6px; }
.search-modal { width: min(680px, 100%); }
.teacher-search-modal { width: min(760px, 100%); }
.search-time-heading { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; margin-top: 18px; color: var(--navy); font-size: 12px; font-weight: 750; }
.search-time-heading .muted-text { margin: 0; font-size: 10px; font-weight: 500; }
.search-time-options { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; max-height: 220px; overflow: auto; margin-top: 9px; padding: 2px; }
.search-time-option { display: flex; align-items: flex-start; gap: 8px; padding: 10px; border: 1px solid var(--line); background: #fbfcfd; color: var(--ink); font-size: 11px; line-height: 1.4; cursor: pointer; }
.search-time-option:hover { border-color: #a9c4d4; background: var(--blue-soft); }
.search-time-option input { margin-top: 2px; accent-color: var(--blue); }
.search-results { min-height: 68px; max-height: 230px; overflow: auto; margin-top: 14px; padding: 12px; border: 1px solid #e9eef1; background: #f7f9fa; color: var(--muted); font-size: 11px; line-height: 1.55; }
.search-result { padding: 9px 0; border-bottom: 1px solid var(--line); }
.search-result:first-child { padding-top: 0; }
.search-result:last-child { padding-bottom: 0; border-bottom: 0; }
.search-result strong { color: var(--navy); font-size: 13px; }
.pending-courses { display: grid; gap: 6px; margin-top: 14px; }
.pending-label { color: var(--muted); font-size: 11px; font-weight: 700; }
.pending-course { display: flex; align-items: center; justify-content: space-between; padding: 8px 10px; background: var(--blue-soft); border-left: 3px solid var(--blue); color: var(--navy); font-size: 11px; }
.remove-pending { border: 0; background: transparent; color: var(--muted); font-size: 17px; line-height: 1; padding: 0 2px; }
.remove-pending:hover { color: var(--danger); }
.search-result-name { margin-left: 8px; color: var(--muted); }
.search-result-sessions { margin-top: 4px; }
.teacher-result { padding: 10px 0; border-bottom: 1px solid var(--line); }
.teacher-result:last-child { border-bottom: 0; }
.teacher-result strong { color: var(--navy); font-size: 14px; }
.teacher-result-course { margin-top: 8px; color: var(--navy); font-size: 12px; font-weight: 750; }
.teacher-result-sessions { margin-top: 3px; color: var(--muted); font-size: 11px; }
.teacher-result-note { margin-top: 7px; padding: 7px 9px; background: #fffaf0; border-left: 3px solid #d27a36; color: var(--muted); font-size: 11px; }
.teacher-picker { max-height: 180px; overflow: auto; margin-top: 14px; padding: 10px; border: 1px solid var(--line); background: #fbfcfd; }
.teacher-picker-heading { margin-bottom: 8px; color: var(--muted); font-size: 11px; line-height: 1.5; }
.teacher-picker-option { display: grid; grid-template-columns: auto 145px 1fr; align-items: center; gap: 8px; padding: 6px 0; border-top: 1px solid #edf1f3; color: var(--navy); font-size: 11px; }
.teacher-picker-option small { color: var(--muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.teacher-assignment-modal { width: min(560px, 100%); }
.teacher-class-options { max-height: 240px; overflow: auto; margin-top: 14px; padding: 10px; border: 1px solid var(--line); background: #fbfcfd; }
.confirm-modal { width: min(500px, 100%); }
.teacher-bulk-label { margin-top: 16px; }
.teacher-bulk-help { margin-top: 5px; color: var(--muted); font-size: 10px; line-height: 1.5; }
.admin-modal { width: min(720px, 100%); }
.admin-toolbar { display: flex; justify-content: space-between; align-items: center; color: var(--muted); font-size: 11px; border-bottom: 1px solid var(--line); padding-bottom: 12px; }
.admin-users { display: grid; gap: 9px; max-height: 52vh; overflow: auto; padding-top: 13px; }
.admin-user { border: 1px solid var(--line); padding: 13px; background: #fbfcfd; }
.admin-user-head { display: flex; justify-content: space-between; gap: 10px; color: var(--navy); font-size: 13px; }
.admin-role { color: var(--blue); font-size: 10px; font-weight: 700; }
.admin-user-meta, .admin-user-courses, .admin-empty { color: var(--muted); font-size: 11px; line-height: 1.6; margin-top: 6px; }

@media (max-width: 900px) {
  .app-shell { display: block; }
  .sidebar { width: 100%; max-height: none; padding: 20px 16px; }
  .course-catalog { max-height: 300px; }
  .main-content { min-width: 0; max-width: none; padding: 28px 20px 40px; }
  .topbar { flex-direction: column; gap: 16px; }
  .topbar-actions { width: 100%; flex-wrap: wrap; padding-top: 0; }
  .workspace { overflow-x: auto; }
  .timetable { min-width: 880px; }
  .stats-row { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 600px) {
  .sidebar { padding: 18px 12px; }
  .sidebar-section { padding-left: 4px; padding-right: 4px; }
  .brand { padding-bottom: 20px; }
  .main-content { padding: 22px 12px 30px; }
  .topbar h1 { font-size: 25px; }
  .topbar-actions { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
  .user-bar { grid-column: 1 / -1; justify-content: flex-start; }
  .topbar-actions .secondary-button, .topbar-actions .primary-button { width: 100%; padding: 9px 7px; font-size: 11px; }
  .stats-row { grid-template-columns: 1fr 1fr; gap: 8px; }
  .stat-card, .status-card { padding: 13px 10px; }
  .workspace-header { height: auto; min-height: 62px; padding: 12px 14px; align-items: flex-start; gap: 8px; }
  .view-caption { display: none; }
  .form-grid { grid-template-columns: 1fr; }
  .modal { padding: 19px; }
  .modal-actions { flex-wrap: wrap; }
  .modal-actions button { flex: 1 1 auto; }
  .search-time-options { grid-template-columns: 1fr; }
  .teacher-picker-option { grid-template-columns: auto 80px 1fr; }
}

/* Collapsible left navigation and responsive layout */
.sidebar { position: fixed; inset: 0 auto 0 0; z-index: 20; height: 100vh; transition: transform .22s ease; }
.main-content { width: calc(100% - 310px); max-width: none; margin-left: 310px; min-width: 0; transition: margin-left .22s ease, width .22s ease; }
body.sidebar-collapsed .sidebar { transform: translateX(-100%); }
body.sidebar-collapsed .main-content { width: 100%; margin-left: 0; }
.sidebar-toggle-button { display: inline-flex; align-items: center; gap: 5px; }
.sidebar-collapse-button { display: flex; align-items: center; justify-content: center; gap: 6px; width: 100%; margin-top: 14px; padding: 8px; border: 1px solid rgba(255,255,255,.2); border-radius: 3px; background: rgba(255,255,255,.08); color: #eaf3f8; font-size: 12px; font-weight: 750; }
.sidebar-collapse-button:hover { background: rgba(255,255,255,.16); }
.sidebar-handle-button { position: fixed; top: 50%; left: 294px; z-index: 31; width: 26px; height: 58px; transform: translateY(-50%); border: 1px solid rgba(255,255,255,.4); border-left: 0; border-radius: 0 8px 8px 0; background: var(--navy); color: #fff; font-size: 25px; line-height: 1; box-shadow: 2px 0 10px rgba(20,43,60,.18); transition: left .22s ease; }
.sidebar-handle-button:hover { background: var(--blue); }
body.sidebar-collapsed .sidebar-handle-button { left: 0; border-left: 1px solid rgba(255,255,255,.4); }
.notice-button { border: 1px solid #d6a932; color: #8a6500; }
.notice-modal { width: min(680px, 100%); }
.notice-content { color: var(--ink); font-size: 12px; line-height: 1.75; }
.notice-content h3 { margin: 0 0 12px; color: #9b6d00; font-size: 14px; }
.notice-content ul { margin: 0 0 13px; padding-left: 22px; }
.notice-content p { margin: 12px 0; }
.notice-content a { color: var(--blue); }
.notice-warning { padding: 12px 14px; border-left: 4px solid #e1b43b; background: #fff8df; }

@media (max-width: 1180px) {
  .sidebar { width: 270px; flex-basis: 270px; }
  .main-content { width: calc(100% - 270px); margin-left: 270px; }
  body.sidebar-collapsed .main-content { width: 100%; margin-left: 0; }
  .sidebar-handle-button { left: 254px; }
}
@media (max-width: 900px) {
  .app-shell { display: block; }
  .sidebar { width: 250px; max-height: 100vh; padding: 20px 14px; }
  .main-content { width: 100%; margin-left: 0; max-width: none; padding: 28px 18px 40px; }
  .topbar { flex-direction: column; gap: 16px; }
  .topbar-actions { width: 100%; flex-wrap: wrap; padding-top: 0; }
  .workspace { overflow-x: auto; }
  .timetable { min-width: 880px; }
  body.sidebar-collapsed .main-content { width: 100%; margin-left: 0; }
  .sidebar-handle-button { left: 234px; }
}
@media (max-width: 600px) {
  .sidebar { width: 235px; padding: 18px 11px; }
  .main-content { width: 100%; margin-left: 0; padding: 20px 10px 30px; }
  .topbar h1 { font-size: 23px; }
  .topbar-actions { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 7px; }
  .user-bar { grid-column: 1 / -1; justify-content: flex-start; }
  .topbar-actions .secondary-button, .topbar-actions .primary-button { width: 100%; padding: 8px 5px; font-size: 10px; }
  .stats-row { grid-template-columns: 1fr 1fr; gap: 7px; }
  .workspace-header { min-height: 60px; padding: 10px 12px; }
  body.sidebar-collapsed .main-content { width: 100%; margin-left: 0; }
}

/* Sidebar section headings and semester reminder */
.sidebar .section-label { font-size: 15px; letter-spacing: .5px; margin-bottom: 14px; }
.course-search-help { color: #c7d7e2; font-size: 11px; line-height: 1.5; margin: -4px 0 10px; }
.semester-notice { margin-top: 16px; padding-top: 16px; padding-bottom: 8px; border-top: 1px solid rgba(255,255,255,.15); }
.semester-notice strong { display: block; color: #f4f8fb; font-size: 13px; line-height: 1.45; }
.semester-notice span { display: block; margin-top: 5px; color: #9db4c8; font-size: 10px; line-height: 1.45; }