:root {
  --bg: #f6f7f2;
  --paper: #ffffff;
  --ink: #20231f;
  --muted: #687065;
  --line: #d9ded2;
  --accent: #1f7a62;
  --accent-dark: #145744;
  --gold: #b7791f;
  --blue: #2d6cdf;
  --red: #bb3e3e;
  --shadow: 0 14px 40px rgba(35, 43, 33, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: Inter, "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
  letter-spacing: 0;
}

button,
input,
select,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  gap: 24px;
  align-items: center;
  padding: 14px 28px;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(14px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: inherit;
  text-decoration: none;
}

.brand-mark {
  display: block;
  width: 42px;
  height: 42px;
  border-radius: 8px;
  object-fit: contain;
  flex: none;
}

.brand small,
.eyebrow,
.panel-title span,
label span,
.resource-meta,
.question-meta {
  color: var(--muted);
}

.brand small {
  display: block;
  margin-top: 2px;
}

.nav-tabs,
.status-chips,
.resource-actions,
.dialog-actions,
.section-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.nav-tab,
.ghost-btn,
.primary-btn,
.icon-btn {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: 10px 14px;
}

.nav-tab.active,
.primary-btn {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
}

.ghost-btn:hover,
.nav-tab:hover {
  border-color: var(--accent);
}

main {
  width: min(1440px, calc(100% - 32px));
  margin: 0 auto 48px;
}

.login-gate {
  width: min(1180px, calc(100% - 32px));
  min-height: calc(100vh - 88px);
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.75fr);
  gap: 18px;
  align-items: center;
}

.login-card {
  display: grid;
  gap: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  padding: 28px;
  box-shadow: var(--shadow);
}

.login-card p {
  color: var(--muted);
  line-height: 1.7;
}

body[data-portal="student"] .teacher-login-card,
body[data-portal="teacher"] .student-login-card {
  display: none;
}

body[data-portal="teacher"] .login-gate {
  grid-template-columns: minmax(320px, 640px);
  justify-content: center;
}

.text-link {
  color: var(--blue);
  font-weight: 800;
  text-decoration: none;
}

.account-hint {
  border: 1px solid #dfe7dc;
  border-radius: 8px;
  padding: 10px 12px;
  background: #f7faf3;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(360px, 0.8fr);
  gap: 40px;
  align-items: end;
  padding: 56px 0 28px;
}

.eyebrow {
  margin: 0 0 8px;
  text-transform: uppercase;
  font-size: 12px;
  font-weight: 700;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 18px;
  max-width: 780px;
  font-size: clamp(40px, 7vw, 84px);
  line-height: 0.98;
}

h2 {
  margin-bottom: 0;
  font-size: 28px;
}

h3 {
  margin-bottom: 10px;
}

.hero-copy {
  max-width: 760px;
  color: #4c5549;
  font-size: 18px;
  line-height: 1.7;
}

.how-to {
  display: grid;
  gap: 12px;
}

.how-to div,
.toolbar,
.unit-list,
.unit-detail,
.questions-view,
.teacher-view,
dialog {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  box-shadow: var(--shadow);
}

.how-to div {
  display: grid;
  grid-template-columns: 42px 1fr;
  gap: 12px;
  align-items: center;
  padding: 18px;
}

.how-to strong {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font-size: 20px;
}

.how-to span {
  color: #394338;
  font-weight: 700;
}

.toolbar {
  display: grid;
  grid-template-columns: minmax(220px, 320px) minmax(260px, 1fr) minmax(260px, 360px);
  gap: 12px;
  padding: 14px;
  margin-bottom: 18px;
}

.progress-panel,
.teacher-progress {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  box-shadow: var(--shadow);
  padding: 16px;
  margin-bottom: 18px;
}

.progress-panel p,
.teacher-progress p {
  margin: 4px 0 0;
  color: var(--muted);
}

label {
  display: grid;
  gap: 6px;
}

label span {
  font-size: 12px;
  font-weight: 700;
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 11px 12px;
  background: #fbfcf8;
  color: var(--ink);
}

textarea {
  resize: vertical;
}

textarea[readonly] {
  min-height: 58px;
  color: #425043;
}

.resource-note {
  display: grid;
  align-content: center;
  gap: 4px;
  border: 1px solid #dfe7dc;
  border-radius: 8px;
  padding: 10px 12px;
  background: #f7faf3;
}

.resource-note span {
  color: var(--muted);
  font-size: 13px;
}

.layout {
  display: grid;
  grid-template-columns: 360px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.unit-list,
.unit-detail,
.questions-view,
.teacher-view {
  padding: 16px;
}

.unit-list {
  position: sticky;
  top: 86px;
  max-height: calc(100vh - 110px);
  overflow: auto;
}

.panel-title,
.unit-heading,
.section-heading,
.dialog-head {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: center;
}

.unit-button {
  width: 100%;
  margin-top: 8px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: transparent;
  padding: 12px;
  text-align: left;
}

.unit-button:hover,
.unit-button.active {
  background: #edf4ef;
  border-color: #c5d8cf;
}

.unit-button strong,
.unit-button span {
  display: block;
}

.unit-button span {
  margin-top: 4px;
  color: var(--muted);
  font-size: 13px;
}

.topic-list {
  display: grid;
  gap: 14px;
  margin-top: 18px;
}

.topic-card,
.question-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 16px;
  background: #fff;
}

.topic-head {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
  margin-bottom: 14px;
}

.topic-id,
.chip,
.pill {
  display: inline-flex;
  align-items: center;
  min-height: 26px;
  border-radius: 999px;
  padding: 3px 9px;
  background: #eef1ea;
  color: #425043;
  font-size: 12px;
  font-weight: 700;
}

.lesson-summary {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}

.pill.ready {
  background: #e6f2ec;
  color: var(--accent-dark);
}

.pill.partial {
  background: #eef4ff;
  color: var(--blue);
}

.pill.readingOnly,
.pill.videoOnly,
.pill.practiceOnly,
.pill.guided {
  background: #fff8ea;
  color: #77591d;
}

.pill.progress-state {
  background: #eef1ea;
  color: #425043;
}

.pill.missing {
  background: #f2eee7;
  color: #7a5a27;
}

.topic-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.next-step {
  margin: 10px 0 14px;
  border-left: 4px solid var(--accent);
  padding: 10px 12px;
  background: #eef7f1;
  color: #285541;
  line-height: 1.55;
}

.lesson-path {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 12px;
}

.path-step {
  display: grid;
  align-content: start;
  gap: 10px;
  border: 1px solid #e2e6dd;
  border-radius: 8px;
  padding: 12px;
  background: #fbfcf8;
}

.path-step-head {
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 10px;
  align-items: start;
}

.path-step-head span {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font-weight: 800;
}

.path-step h4 {
  margin: 0;
  color: var(--accent-dark);
  font-size: 15px;
}

.path-step p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.more-resources {
  border-top: 1px solid #e2e6dd;
  padding-top: 8px;
}

.more-resources summary {
  color: var(--blue);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
}

.resource-item {
  display: grid;
  gap: 8px;
  border-top: 1px solid #e2e6dd;
  padding-top: 10px;
}

.inline-note {
  border-top: 1px solid #e2e6dd;
  padding-top: 10px;
}

.inline-note p {
  margin: 8px 0 0;
  color: #374238;
  font-size: 14px;
  line-height: 1.55;
}

.exercise-card {
  display: grid;
  gap: 10px;
  border-top: 1px solid #e2e6dd;
  padding-top: 10px;
}

.exercise-card.saved textarea {
  border-color: var(--accent);
  background: #f2fbf5;
}

.exercise-title {
  color: var(--accent-dark);
  font-weight: 800;
}

.exercise-card p {
  margin: 0;
  line-height: 1.6;
}

.answer-panel {
  border: 1px solid #dfe7dc;
  border-radius: 8px;
  padding: 10px 12px;
  background: #fff;
}

.answer-panel summary {
  color: var(--blue);
  font-weight: 800;
  cursor: pointer;
}

.answer-panel p {
  margin-top: 10px;
  white-space: pre-line;
}

.resource-title {
  margin: 0 0 6px;
  font-weight: 700;
  line-height: 1.35;
  font-size: 14px;
}

.resource-meta {
  display: -webkit-box;
  overflow: hidden;
  min-height: 34px;
  font-size: 12px;
  line-height: 1.45;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.resource-actions {
  margin-top: 0;
}

.learn-link,
.mini-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 34px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 7px 10px;
  background: #fff;
  color: var(--ink);
  text-decoration: none;
  font-size: 13px;
  font-weight: 700;
}

.learn-link {
  border-color: var(--blue);
  color: var(--blue);
}

.mini-btn:hover,
.learn-link:hover {
  background: #eef4ff;
}

.question-grid,
.teacher-list {
  display: grid;
  gap: 12px;
  margin-top: 18px;
}

.question-card header {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  align-items: start;
}

.question-card p {
  line-height: 1.6;
}

.status {
  border-radius: 999px;
  padding: 4px 9px;
  color: #fff;
  font-size: 12px;
  font-weight: 800;
  white-space: nowrap;
}

.status.submitted {
  background: var(--gold);
}

.status.reviewing {
  background: var(--blue);
}

.status.answered {
  background: var(--accent);
}

.status.closed {
  background: var(--muted);
}

.teacher-reply {
  margin-top: 12px;
  border-left: 4px solid var(--accent);
  padding: 10px 12px;
  background: #eef6f1;
}

.teacher-controls {
  display: grid;
  grid-template-columns: 170px minmax(0, 1fr) 220px auto;
  gap: 10px;
  align-items: end;
  margin-top: 12px;
}

.teacher-action-stack {
  display: grid;
  gap: 8px;
}

.teacher-question-actions,
.reply-image-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 12px;
}

.lesson-focus {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

.teacher-lesson-return {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin: 12px 0;
  padding: 10px 12px;
  border: 1px solid var(--line);
  background: #f7faf7;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

.image-zoom {
  padding: 0;
  border: 0;
  background: transparent;
  cursor: zoom-in;
}

.reply-image-item {
  display: grid;
  justify-items: start;
  gap: 6px;
}

.image-error {
  color: #a02727;
  font-weight: 700;
}

.image-error:empty {
  display: none;
}

.image-dialog {
  width: min(96vw, 1200px);
  max-height: 94vh;
  padding: 12px;
}

.image-dialog form {
  display: flex;
  justify-content: flex-end;
}

.image-dialog img {
  display: block;
  max-width: 100%;
  max-height: calc(94vh - 70px);
  margin: auto;
  object-fit: contain;
}

.context-box {
  margin-top: 12px;
  border: 1px solid #dfe7dc;
  border-radius: 8px;
  padding: 12px;
  background: #fbfcf8;
}

.context-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  margin-bottom: 10px;
}

.context-box dl {
  display: grid;
  grid-template-columns: 160px minmax(0, 1fr);
  gap: 8px 12px;
  margin: 0;
}

.context-box dt {
  color: var(--muted);
  font-weight: 800;
}

.context-box dd {
  margin: 0;
  line-height: 1.55;
}

.context-box dd p {
  margin: 0 0 6px;
}

.image-preview,
.attached-image {
  border: 1px solid #dfe7dc;
  border-radius: 8px;
  padding: 10px;
  background: #fbfcf8;
}

.image-preview img,
.attached-image img {
  display: block;
  max-width: min(560px, 100%);
  max-height: 320px;
  border-radius: 8px;
  margin-top: 8px;
  object-fit: contain;
}

.teacher-filter {
  display: grid;
  grid-template-columns: minmax(180px, 260px) minmax(160px, 220px) minmax(260px, 1fr);
  gap: 12px;
  margin-top: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px;
  background: #fbfcf8;
}

.teacher-progress {
  display: grid;
  align-items: stretch;
}

.teacher-progress-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
}

.teacher-progress-head h3 {
  margin: 0;
}

.progress-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 10px;
  margin-top: 12px;
}

.progress-card {
  border: 1px solid #e2e6dd;
  border-radius: 8px;
  padding: 12px;
  background: #fbfcf8;
}

.progress-card span {
  display: block;
  margin-top: 4px;
  color: var(--muted);
}

.progress-bar {
  height: 8px;
  border-radius: 999px;
  background: #e7ece3;
  overflow: hidden;
  margin: 10px 0;
}

.progress-bar i {
  display: block;
  height: 100%;
  background: var(--accent);
}

.hidden {
  display: none !important;
}

dialog {
  width: min(680px, calc(100vw - 28px));
  padding: 0;
  border: none;
}

dialog::backdrop {
  background: rgba(20, 25, 20, 0.46);
}

.ask-form {
  display: grid;
  gap: 14px;
  padding: 20px;
}

.icon-btn {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  padding: 0;
  font-size: 24px;
}

.form-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.empty {
  border: 1px dashed var(--line);
  border-radius: 8px;
  padding: 26px;
  color: var(--muted);
  text-align: center;
}

  @media (max-width: 920px) {
  .topbar,
  .hero,
  .layout,
  .toolbar,
  .teacher-controls,
  .lesson-path,
  .login-gate,
  .teacher-filter,
  .progress-panel {
    grid-template-columns: 1fr;
  }

  .context-box dl {
    grid-template-columns: 1fr;
  }

  .progress-panel {
    align-items: flex-start;
    flex-direction: column;
  }

  .topbar,
  .panel-title,
  .unit-heading,
  .section-heading {
    align-items: flex-start;
    flex-direction: column;
  }

  .unit-list {
    position: static;
    max-height: 320px;
  }

  .form-row {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 560px) {
  main {
    width: min(100% - 20px, 1440px);
  }

  .topbar {
    padding: 12px;
  }

  .hero {
    padding-top: 34px;
  }

  .form-row,
  .lesson-path {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 38px;
  }
}