/* Match the platform workspace's palette, typography, surfaces and controls. */
:root {
  --green:#2563EB; --deep:#1746A2; --mint:#EAF3FF; --bg:#F5FAFF;
  --ink:#183153; --muted:#687B91; --line:#DCE8F4; --white:#fff;
  --orange:#F59E0B; --shadow:0 8px 28px rgba(37,99,235,.09);
  font-family:Arial,"Microsoft YaHei",sans-serif;
  color:var(--ink); background:var(--bg);
}
body {background:var(--bg);color:var(--ink);font-size:15px;line-height:1.75}
button,input,select,textarea {font-family:inherit}
button {border-radius:10px;font-size:14px;font-weight:650;border-color:var(--line);color:var(--ink)}
button:hover {border-color:#A9CDF0;background:#F0F7FF}
button:focus-visible,a:focus-visible {outline:3px solid #2563EB;outline-offset:3px}
.primary,.page-heading a.primary {
  display:inline-flex;align-items:center;justify-content:center;gap:7px;
  padding:10px 17px;border:1px solid #2563EB;border-radius:10px;
  background:linear-gradient(135deg,#2563EB,#1687D9);color:white;
  box-shadow:0 5px 14px rgba(37,99,235,.12);font-weight:750;font-size:14px;text-decoration:none;
}
.primary:hover,.page-heading a.primary:hover {background:linear-gradient(135deg,#1746A2,#0E7490);color:white}
.quiet {background:transparent;border-color:transparent}
.small {font-size:13px;padding:6px 11px}
input,select,textarea {border-color:#CEDDEB;border-radius:10px;font-size:14px}
input:focus,select:focus,textarea:focus {outline:2px solid #93C5FD80;border-color:#2563EB}
label,.field label {font-size:14px;font-weight:750}
h1 {font-size:clamp(27px,2.5vw,34px);font-weight:800;letter-spacing:0;line-height:1.4}
h2 {font-weight:750;line-height:1.5} h3 {font-weight:750}
.eyebrow {color:var(--deep);font-size:12px;font-weight:800;letter-spacing:.08em;margin-bottom:5px}
.note,.form-hint {font-size:13px;color:var(--muted)}
.layout {grid-template-columns:240px minmax(0,1fr);min-height:calc(100vh - var(--site-header-height,82px))}
.sidebar {
  background:white;border-color:var(--line);padding:24px 16px;gap:24px;
  top:var(--site-header-height,82px);height:calc(100vh - var(--site-header-height,82px));
}
.brand {color:var(--ink);font-size:21px;font-weight:800;letter-spacing:0}
.brand-icon {background:linear-gradient(135deg,#2563EB,#14B8A6);border-radius:11px;width:38px;height:38px;color:white;box-shadow:0 5px 14px #2563EB20}
.brand small {font-size:10px;letter-spacing:.08em;color:var(--muted)}
.nav-label {font-size:11px;font-weight:800;letter-spacing:.08em;color:#8193A6;margin-left:12px}
.nav-item {min-height:46px;border-radius:10px;padding:10px 13px;font-size:14px;font-weight:700;color:#536B82;align-items:center}
.nav-item:hover,.nav-item.active {background:linear-gradient(90deg,#EAF3FF,#E5FAF5);color:var(--deep)}
.nav-item.active {box-shadow:inset 3px 0 #2563EB}
.nav-dot {color:var(--deep);background:#EAF3FF;border-radius:6px;padding:1px 7px;font-size:12px}
.sidebar-bottom {border-color:var(--line)}
.avatar {background:var(--mint);color:var(--deep);font-weight:800}
.user-name {font-size:14px;font-weight:700}.user-role {font-size:12px}
.sidebar-actions {gap:8px;flex-wrap:wrap}.sidebar-actions a {color:var(--deep);font-size:13px;text-decoration:none}
.topbar {min-height:64px;height:auto;padding:15px 32px;background:linear-gradient(90deg,#FFFFFF,#F4FAFF);color:var(--muted);font-size:13px;gap:12px}
.online {color:var(--muted)}.online:before {background:#14B8A6}
.content {max-width:1500px;padding:32px;min-width:0}
.page-heading {margin-bottom:24px}.page-heading p {font-size:14px;margin-top:8px;max-width:800px}
.welcome {background:linear-gradient(110deg,#FFFFFF,#F0F8FF 65%,#ECFBF7);border:1px solid #BDD8F2;border-left:4px solid #2563EB;border-radius:12px;padding:24px;margin-bottom:24px}
.welcome h2 {font-size:20px;color:var(--ink)}.welcome p {font-size:14px;color:var(--muted)}
.stats {display:grid;grid-template-columns:repeat(4,minmax(72px,1fr));gap:12px;flex-shrink:0}
.stat {background:white;border:1px solid var(--line);border-radius:10px;padding:12px 16px;min-width:76px}
.stat strong {font-size:25px;font-weight:800;color:var(--deep);line-height:1.4;margin-bottom:3px}
.stat span {font-size:12px;color:var(--muted)}
.tabs {gap:8px;flex-wrap:wrap}.tabs button {border:0;border-radius:8px;padding:9px 14px;font-weight:700}
.tabs button.active {background:var(--mint);color:var(--deep);border:0;box-shadow:inset 0 -2px #2563EB}
.toolbar {gap:14px;flex-wrap:wrap}.toolbar>.flex {flex-wrap:wrap}.search {max-width:320px}
.tag {background:var(--mint);color:var(--deep);border-radius:6px;font-size:12px;padding:3px 8px}
.tag.submitted {background:#FFF4DB;color:#925F00}.tag.reviewed {background:#E1F8F1;color:#087A67}.tag.returned {background:#FFF0F2;color:#B8334A}
.table-wrap {background:white;border:1px solid var(--line);border-top:3px solid #A9CDF0;border-radius:12px;box-shadow:var(--shadow)}
table {width:100%;border-collapse:collapse;background:white}
th {background:#F0F6FE;color:#536B82;font-size:12px;font-weight:750;text-align:left}
th,td {padding:13px 16px;border-bottom:1px solid #E9F0F6}
td {font-size:14px;color:var(--ink)}tbody tr:hover {background:#FAFDFF}
.cards {gap:20px}.doc-card {border-radius:14px;border-top:3px solid #6EA8FE;box-shadow:0 4px 15px #2563EB08}
.doc-card:nth-child(3n+2) {border-top-color:#55D6BE}.doc-card:nth-child(3n) {border-top-color:#FFCC4C}
.doc-thumb {background-color:#F0F7FF;background-image:linear-gradient(#D9E8F680 1px,transparent 1px),linear-gradient(90deg,#D9E8F680 1px,transparent 1px);color:#4E8DBD}
.doc-card h3 {font-size:17px}.doc-card p {font-size:13px}.doc-meta {border-color:#E9F0F6;font-size:12px;color:var(--muted)}
.empty {border:1px dashed #BDD3EA;border-radius:14px;background:white;padding:48px 24px}.empty-icon {color:#6EA8FE}.empty p {font-size:14px}
.panel {background:white;border-color:var(--line);border-radius:12px;box-shadow:0 4px 15px #2563EB06}
.panel-head {background:#FAFDFF;border-color:var(--line);font-weight:750}
.editor-heading h1 {font-size:28px}.editor-form label {font-size:13px}.editor-form input {font-size:14px}
.editor-note {background:#EAF3FF;border-color:#C7DCF4;color:#3C618C;border-radius:10px;font-size:13px}
.preview-wrap,.drawing-preview {background:white;border-color:var(--line);border-radius:12px}
.feature {background:#FAFDFF;border-color:var(--line);border-radius:10px}
.credentials {background:#F0F6FE;border-color:var(--line);color:var(--ink)}
dialog {border:1px solid var(--line);border-radius:16px;box-shadow:0 24px 80px #18315330}
dialog::backdrop {background:#18315350;backdrop-filter:blur(3px)}
.group-intro p {font-size:14px}.group-column {border-color:var(--line);box-shadow:0 4px 15px #2563EB06}
.group-column>header {background:linear-gradient(90deg,#EAF3FF,#EDF9FF);border-bottom:1px solid var(--line)}
.group-column.unassigned>header {background:#FFF9E8}
.group-dropzone.drop-active {background:#EAF3FF;box-shadow:inset 0 0 0 2px #2563EB}
.group-student {border-color:var(--line);background:white;border-radius:10px}.group-student-name {font-size:14px}.group-grip {color:#8193A6}.group-empty {color:var(--muted)}
.bottom-note {color:var(--muted);font-size:12px}.content a:not(.primary) {color:var(--deep)}
@media(max-width:1200px) {.welcome{align-items:flex-start;flex-wrap:wrap}.content{padding:26px}.topbar{padding-inline:26px}}
@media(max-width:900px) {.layout{grid-template-columns:210px minmax(0,1fr)}.sidebar{padding:22px 12px}.stats{grid-template-columns:repeat(2,minmax(100px,1fr));width:100%}.content{padding:24px}.editor-layout{grid-template-columns:minmax(0,1fr)}}
@media(max-width:700px) {
  .layout{display:block;min-height:calc(100vh - var(--site-header-height,130px))}
  .sidebar{position:static;display:flex;flex-direction:row;align-items:center;gap:8px;height:auto;padding:8px 12px;border-right:0;border-bottom:1px solid var(--line);overflow-x:auto}
  .sidebar>.brand,.sidebar .nav-label,.sidebar-bottom{display:none}
  .sidebar>nav{display:flex;gap:7px;align-items:center;min-width:max-content}
  .nav-item{width:auto;margin:0;min-height:40px;font-size:13px;white-space:nowrap}
  .nav-item.active{box-shadow:inset 0 -2px #2563EB}.nav-dot{margin-left:6px}
  .topbar{min-height:52px;padding:10px 14px;font-size:12px}.topbar .online{display:none}
  .content{padding:20px 14px}.page-heading{gap:12px;flex-wrap:wrap}.page-heading h1{font-size:27px}.page-heading p{font-size:14px}
  .welcome{display:block;padding:18px;margin-bottom:20px}.welcome h2{font-size:19px}.welcome p{font-size:13px}
  .stats{margin-top:18px;gap:10px}.stat{padding:12px}.stat strong{font-size:24px}
  .toolbar{align-items:flex-start}.tabs{gap:4px}.tabs button{padding:8px 11px;font-size:13px}
  .cards{grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:14px}
  .editor-heading h1{font-size:24px}.editor-actions{gap:7px}.editor-actions button{font-size:13px}
  .search{max-width:100%;width:100%}.group-intro h2{font-size:19px}
  th,td{padding:11px 12px}.ui-header{position:relative}
}
@media(prefers-reduced-motion:reduce) {button,.doc-card{transition:none}.doc-card:hover{transform:none}}
.drawing-start{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(220px,.8fr);align-items:center;gap:30px;padding:30px;margin-bottom:32px;background:linear-gradient(120deg,#fff,#eaf3ff 70%,#e5faf5);border:1px solid #c6ddf5;border-radius:16px}.drawing-start h2{font-size:25px;margin:12px 0}.drawing-start p{color:var(--muted);margin-bottom:22px;max-width:650px}.drawing-start .flex{flex-wrap:wrap}.drawing-example{color:#397ec0;padding:20px}.drawing-example svg{width:100%;max-height:250px}.drawing-steps{font-size:13px;color:var(--muted);margin-top:22px}@media(max-width:700px){.drawing-start{grid-template-columns:1fr;padding:22px}.drawing-example{display:none}.drawing-start h2{font-size:22px}}