:root {
  --bg: #eef1f5;
  --paper: #ffffff;
  --line: #e6ebf1;
  --line-dark: #c8d0da;
  --ink: #20242a;
  --sub: #606873;
  --muted: #8b949f;
  --orange: #ff7a2f;
  --orange-soft: #fff1e8;
  --blue: #247cff;
  --green: #2ebe71;
  --teal: #10b8ad;
  --purple: #6554e8;
  --shadow: 0 16px 45px rgba(21, 34, 51, 0.08);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }
body { margin: 0; color: var(--ink); background: var(--bg); }
button, input { font: inherit; }
button {
  height: 36px;
  padding: 0 18px;
  border: 1px solid var(--line-dark);
  background: #fff;
  color: #3b414a;
}
button.primary { border-color: var(--orange); background: var(--orange); color: #fff; }
button.light { border-color: #fff; background: #fff; color: var(--orange); }
input {
  height: 36px;
  border: 1px solid var(--line-dark);
  padding: 0 12px;
  outline: none;
}
a { color: var(--orange); text-decoration: none; margin-right: 14px; }

.prototype-board { padding: 28px 34px 56px; }
.board-head {
  max-width: 1680px;
  margin: 0 auto 26px;
  display: flex;
  align-items: end;
  justify-content: space-between;
}
.board-head h1 { margin: 0; font-size: 30px; letter-spacing: 0; }
.board-head p, .board-head span { margin: 6px 0 0; color: var(--muted); }
.screen-row { max-width: 1680px; margin: 0 auto 44px; }
.screen-label {
  display: flex;
  align-items: end;
  justify-content: space-between;
  padding: 0 2px 12px;
}
.screen-label strong { font-size: 20px; }
.screen-label span { color: var(--muted); }
.screen {
  width: 1680px;
  min-height: 920px;
  overflow: hidden;
  background: var(--bg);
  box-shadow: var(--shadow);
}

.topbar {
  height: 58px;
  display: flex;
  align-items: center;
  gap: 34px;
  padding: 0 20px;
  background: #fff;
  border-bottom: 1px solid var(--line);
}
.brand {
  width: 190px;
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
}
.brand-mark {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: conic-gradient(from 140deg, #1b8cff, #13b78f, #ff7a2f, #1b8cff);
}
.topnav {
  flex: 1;
  display: flex;
  align-self: stretch;
  align-items: center;
  gap: 42px;
  font-size: 16px;
}
.topnav b {
  height: 58px;
  display: flex;
  align-items: center;
  border-bottom: 3px solid transparent;
}
.topnav b.active { color: var(--orange); border-bottom-color: var(--orange); }
.top-actions { display: flex; align-items: center; gap: 14px; color: var(--sub); font-size: 13px; }
.top-actions input { width: 210px; height: 30px; background: #f8f9fb; }

.home-hero, .search-hero {
  height: 240px;
  background:
    radial-gradient(circle at 18% 0%, rgba(255,255,255,.22) 0 170px, transparent 171px),
    radial-gradient(circle at 76% 18%, rgba(255,255,255,.16) 0 220px, transparent 221px),
    linear-gradient(120deg, #ff8b38, #ff6b2b);
}
.home-hero {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 138px;
  color: #fff;
}
.home-hero span { opacity: .9; }
.home-hero h2 { margin: 12px 0 8px; font-size: 38px; letter-spacing: 0; }
.home-hero p { margin: 0 0 22px; opacity: .9; }
.home-hero aside {
  width: 220px;
  padding: 24px;
  border: 1px solid rgba(255,255,255,.38);
  background: rgba(255,255,255,.14);
}
.home-hero aside b { display: block; font-size: 48px; }
.home-hero aside i, .task-card i, .project-card i, .progress-panel i, .progress-list-card i, .stage-card i {
  display: block;
  height: 8px;
  margin-top: 14px;
  background: rgba(255,255,255,.34);
  overflow: hidden;
}
.home-hero aside em, .task-card em, .project-card em, .progress-panel em, .progress-list-card em, .stage-card em {
  display: block;
  height: 100%;
  background: #fff;
}

.home-grid {
  display: grid;
  grid-template-columns: 390px 1fr 340px;
  gap: 22px;
  padding: 26px 36px 40px;
}
.panel {
  background: #fff;
  border: 1px solid var(--line);
  padding: 22px;
}
.panel-title, .page-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.panel-title h2, .panel h2, .page-title h2 { margin: 0; font-size: 20px; letter-spacing: 0; }
.panel-title { margin-bottom: 18px; }
.todo { min-height: 410px; }
.task-card {
  position: relative;
  margin-bottom: 14px;
  padding: 18px;
  border: 1px solid var(--line);
  background: #fbfcfe;
}
.task-card.strong { border-color: #ffd2b7; background: #fff7f2; }
.task-card b { display: block; margin: 6px 0; font-size: 17px; }
.task-card p { margin: 0; color: var(--muted); }
.task-card i, .project-card i, .progress-panel i, .progress-list-card i { background: #edf1f5; }
.task-card em, .project-card em, .progress-panel em, .progress-list-card em { background: var(--orange); }
.flag {
  display: inline-block;
  padding: 3px 8px;
  font-size: 12px;
  color: var(--orange);
  background: var(--orange-soft);
}
.flag.blue { color: var(--blue); background: #eaf3ff; }
.flag.green { color: var(--green); background: #eafaf1; }
.record p {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  margin: 0;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}
.record span { color: var(--muted); }

.course-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}
.course-grid.compact { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.course-card {
  position: relative;
  min-height: 245px;
  background: #fff;
  border: 1px solid var(--line);
}
.course-card b { display: block; padding: 16px 18px 8px; font-size: 18px; }
.course-card p { margin: 0; padding: 0 18px; color: var(--muted); }
.course-card span {
  position: absolute;
  top: 12px;
  right: 12px;
  padding: 4px 9px;
  color: #fff;
  background: rgba(0,0,0,.62);
  font-size: 12px;
}
.cover {
  height: 128px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 24px;
  background: linear-gradient(135deg, #1968f0, #48a7ff);
}
.cover.blue { background: linear-gradient(135deg, #156de6, #52b6ff); }
.cover.purple { background: linear-gradient(135deg, #5d4be8, #2ab7d6); }
.cover.dark { background: linear-gradient(135deg, #191919, #db4b25); }
.cover.green { background: linear-gradient(135deg, #119c71, #60d48a); }
.cover.orange { background: linear-gradient(135deg, #ff792d, #f7b544); }
.cover.slate { background: linear-gradient(135deg, #334355, #6f7e91); }
.cover.large { width: 280px; height: 170px; flex: 0 0 280px; }

.learn-layout { display: flex; min-height: 862px; }
.profile-side {
  width: 250px;
  flex: 0 0 250px;
  background: #fff;
  border-right: 1px solid var(--line);
  padding: 36px 22px;
}
.avatar {
  width: 74px;
  height: 74px;
  display: grid;
  place-items: center;
  color: #fff;
  font-size: 30px;
  border-radius: 50%;
  background: linear-gradient(135deg, #1783ff, #20c1a6);
}
.profile-side h3 { margin: 18px 0 4px; font-size: 22px; }
.profile-side p { margin: 0 0 22px; color: var(--muted); }
.profile-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 26px; }
.profile-stats span { padding: 12px; background: #f6f8fb; color: var(--muted); }
.profile-stats b { display: block; color: var(--ink); font-size: 20px; }
.profile-side a {
  height: 46px;
  margin: 0 0 6px;
  padding-left: 14px;
  display: flex;
  align-items: center;
  color: #3b414a;
}
.profile-side a.on { color: var(--orange); background: var(--orange-soft); }
.workspace { flex: 1; padding: 24px 30px; }
.center-banner {
  height: 170px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 42px;
  color: #fff;
  background: linear-gradient(110deg, #ff7a2f, #f7aa34);
}
.center-banner h2 { margin: 6px 0; font-size: 34px; letter-spacing: 0; }
.tabs, .knowledge-tabs {
  height: 58px;
  display: flex;
  align-items: center;
  gap: 36px;
  margin-top: 18px;
  padding: 0 30px;
  background: #fff;
}
.tabs b, .knowledge-tabs b, .list-tabs b {
  height: 58px;
  display: flex;
  align-items: center;
  border-bottom: 3px solid transparent;
}
.tabs b.active, .knowledge-tabs b.active, .list-tabs b.active { color: var(--orange); border-bottom-color: var(--orange); }
.filters {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 18px 0;
}
.filters button { height: 34px; }
.filters button.active { color: #fff; border-color: var(--orange); background: var(--orange); }
.filters input { margin-left: auto; width: 240px; }
.project-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.project-card {
  display: flex;
  min-height: 188px;
  background: #fff;
  border: 1px solid var(--line);
}
.project-card > div:last-child { flex: 1; padding: 20px; }
.project-card h3 { margin: 10px 0 8px; font-size: 20px; }
.project-card p { color: var(--muted); margin: 0; }
.project-card button { margin-top: 18px; }
.project-cover {
  width: 190px;
  display: grid;
  place-items: center;
  color: #fff;
  font-size: 24px;
  font-weight: 800;
}
.project-cover.orange { background: linear-gradient(135deg, #ff7a2f, #ffbf52); }
.project-cover.teal { background: linear-gradient(135deg, #0faeab, #5dd6c5); }
.project-cover.green { background: linear-gradient(135deg, #259c55, #7ad487); }
.project-cover.blue { background: linear-gradient(135deg, #1d6fe8, #4ab6ff); }

.detail-head { padding: 26px 118px 12px; }
.crumb { margin-bottom: 16px; color: var(--muted); }
.detail-card, .course-hero-card {
  display: flex;
  gap: 24px;
  padding: 24px;
  background: #fff;
  border: 1px solid var(--line);
}
.detail-cover {
  width: 280px;
  min-height: 175px;
  display: grid;
  place-items: center;
  color: #fff;
  font-size: 28px;
  font-weight: 800;
  background: linear-gradient(135deg, #ff7a2f, #f4b238);
}
.detail-main { flex: 1; }
.detail-main h2, .course-hero-card h2 { margin: 10px 0 8px; font-size: 30px; letter-spacing: 0; }
.detail-main p, .course-hero-card p { color: var(--sub); }
.meta { display: flex; gap: 20px; margin: 18px 0 22px; color: var(--muted); }
.progress-panel {
  width: 230px;
  padding: 18px;
  border-left: 1px solid var(--line);
}
.progress-panel b { display: block; font-size: 44px; color: var(--orange); }
.progress-panel p { color: var(--muted); line-height: 1.7; }
.stage-area { padding: 0 118px 36px; }
.stage-card {
  margin-top: 18px;
  padding: 22px;
  background: #fff;
  border: 1px solid var(--line);
}
.stage-card header {
  display: flex;
  align-items: center;
  gap: 14px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
}
.stage-card header span {
  padding: 5px 10px;
  color: var(--orange);
  background: var(--orange-soft);
}
.stage-card h3 { flex: 1; margin: 0; font-size: 20px; }
.stage-card header b { color: var(--muted); font-size: 14px; }

.lesson-row {
  min-height: 58px;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 0 4px;
  border-bottom: 1px solid var(--line);
}
.lesson-row b {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  color: var(--sub);
  background: #f1f4f8;
}
.lesson-row span { flex: 1; font-weight: 700; }
.lesson-row em { color: var(--muted); font-style: normal; min-width: 190px; }
.lesson-row.done b { color: #fff; background: var(--green); }
.lesson-row.active { background: #fff8f3; }
.lesson-row.active b { color: #fff; background: var(--orange); }

.search-hero {
  height: 240px;
  display: grid;
  place-items: center;
}
.search-hero div { width: 740px; display: flex; }
.search-hero input { flex: 1; height: 48px; border-color: #fff; }
.search-hero button { width: 140px; height: 48px; color: #fff; border-color: #fff; background: transparent; }
.knowledge-shell { max-width: 1060px; margin: 18px auto 0; }
.knowledge-tabs { margin-top: 0; }
.knowledge-body { display: flex; gap: 22px; margin-top: 18px; }
.category-side {
  width: 210px;
  flex: 0 0 210px;
  padding: 20px 0;
  background: #fff;
}
.category-side h3 { margin: 0 20px 18px; font-size: 18px; }
.category-side a {
  height: 38px;
  display: flex;
  align-items: center;
  margin: 0;
  padding-left: 26px;
  color: #3d444d;
}
.category-side a.active { color: var(--orange); background: var(--orange-soft); }
.list-panel { flex: 1; padding: 22px; background: #fff; }
.list-tabs { display: flex; align-items: center; gap: 28px; margin-bottom: 18px; }
.list-tabs span { margin-left: auto; color: var(--muted); }

.course-detail { padding: 42px 100px; }
.course-info-grid { display: grid; grid-template-columns: 1fr 280px; gap: 22px; margin-top: 22px; }
.safe-box p {
  margin: 12px 0 0;
  padding: 13px 14px;
  background: #f7f9fc;
  color: var(--sub);
}

.player-screen { background: #10151d; }
.player-top {
  height: 58px;
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 0 22px;
  color: #fff;
  background: #171d27;
}
.player-top a { color: #fff; }
.player-top b { flex: 1; }
.player-top span { color: #aeb7c3; }
.player-layout { display: flex; min-height: 862px; }
.viewer { flex: 1; position: relative; padding: 42px; }
.watermark {
  position: absolute;
  inset: 90px 340px auto 90px;
  color: rgba(255,255,255,.18);
  font-size: 30px;
  transform: rotate(-18deg);
  pointer-events: none;
}
.video-box {
  height: 640px;
  display: grid;
  place-items: center;
  text-align: center;
  color: #fff;
  background:
    radial-gradient(circle at 40% 40%, rgba(255,122,47,.32), transparent 280px),
    linear-gradient(135deg, #1d2735, #05070a);
}
.video-box h2 { margin: 0; font-size: 38px; letter-spacing: 0; }
.play-circle {
  width: 90px;
  height: 90px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: rgba(255,255,255,.18);
  border: 1px solid rgba(255,255,255,.35);
}
.player-controls {
  height: 78px;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 0 18px;
  background: #171d27;
  color: #c6ced8;
}
.playlist {
  width: 360px;
  flex: 0 0 360px;
  padding: 24px 20px;
  color: #dfe5ec;
  background: #202733;
}
.playlist h3 { margin: 0 0 16px; }
.playlist .lesson-row { border-bottom-color: rgba(255,255,255,.08); }
.playlist .lesson-row b { color: #bac4d0; background: rgba(255,255,255,.08); }
.playlist .lesson-row span { color: #fff; }
.guard-box {
  margin-top: 24px;
  padding: 18px;
  background: rgba(255,122,47,.14);
  border: 1px solid rgba(255,122,47,.35);
}
.guard-box p { margin-bottom: 0; color: #cbd3dd; line-height: 1.7; }

.material-panel {
  margin-top: 18px;
  padding: 34px;
  background: #fff;
}

.material-category {
  height: 46px;
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}

.material-category b {
  margin-right: 6px;
}

.material-category span {
  padding: 7px 12px;
  color: var(--sub);
  background: #f5f7fa;
}

.material-category span.active {
  color: var(--orange);
  background: var(--orange-soft);
}

.material-panel.plain { margin-top: 20px; }
.path-line { margin-bottom: 22px; color: var(--muted); }
table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
}
th {
  height: 46px;
  text-align: left;
  color: #3d444d;
  background: #f6f7f9;
  font-weight: 700;
}
td {
  height: 58px;
  border-bottom: 1px solid var(--line);
  color: #3b414a;
}
th, td { padding: 0 14px; }
.folder, .file {
  width: 17px;
  height: 13px;
  display: inline-block;
  margin-right: 8px;
  background: #ffb23e;
  vertical-align: -1px;
}
.file { height: 16px; background: var(--blue); }
.file.doc { background: var(--orange); }
.file.audio { background: var(--teal); }
.file.video { background: var(--purple); }

.record-page { padding: 32px 56px; }
.page-title { height: 58px; margin-bottom: 20px; }
.page-title p { margin: 6px 0 0; color: var(--muted); }
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
  margin-bottom: 20px;
}
.stats-grid div {
  padding: 24px;
  background: #fff;
  border: 1px solid var(--line);
}
.stats-grid b { display: block; font-size: 32px; color: var(--orange); }
.stats-grid span { color: var(--muted); }
.record-grid { display: grid; grid-template-columns: 1fr 420px; gap: 20px; }
.bars {
  height: 230px;
  display: flex;
  align-items: end;
  gap: 24px;
  padding: 28px 12px 0;
}
.bars i {
  flex: 1;
  min-width: 34px;
  background: linear-gradient(180deg, var(--orange), #ffd4bd);
}
.progress-list-card p {
  display: flex;
  justify-content: space-between;
  margin: 20px 0 8px;
}