:root {
  --primary: #0f766e;
  --primary-dark: #115e59;
  --secondary: #1f2937;
  --warning: #b45309;
  --neutral: #f8fafc;
  --surface: #ffffff;
  --muted: #f1f5f9;
  --border: #d8e0e8;
  --text: #111827;
  --subtle: #64748b;
  --danger: #b91c1c;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--neutral);
  color: var(--text);
  font-family: Inter, "Noto Sans SC", "PingFang SC", system-ui, sans-serif;
}

a {
  color: inherit;
  text-decoration: none;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 14px 28px;
  border-bottom: 1px solid var(--border);
  background: rgba(248, 250, 252, 0.96);
}

.account-menu {
  position: relative;
}

.account-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 0;
  background: transparent;
  cursor: pointer;
  padding: 0;
}

.account-avatar {
  display: grid;
  width: 32px;
  height: 32px;
  place-items: center;
  border-radius: 999px;
  background: #dbeafe;
  color: #2563eb;
  font-size: 13px;
  font-weight: 700;
}

.account-chevron {
  width: 8px;
  height: 8px;
  border-right: 1.5px solid var(--secondary);
  border-bottom: 1.5px solid var(--secondary);
  transform: rotate(45deg) translateY(-2px);
}

.account-dropdown {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  z-index: 30;
  display: none;
  min-width: 132px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.1);
  padding: 6px;
}

.account-menu.open .account-dropdown {
  display: grid;
}

.account-dropdown button {
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: var(--secondary);
  cursor: pointer;
  padding: 9px 10px;
  text-align: left;
  font-size: 14px;
}

.account-dropdown button:hover {
  background: var(--muted);
  color: var(--primary);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 650;
}

.brand-mark {
  display: grid;
  width: 32px;
  height: 32px;
  place-items: center;
  border-radius: 8px;
  background: var(--primary);
  color: #fff;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.nav a {
  border-radius: 8px;
  padding: 8px 10px;
  color: var(--subtle);
  font-size: 14px;
}

.nav a.active,
.nav a:hover {
  background: var(--muted);
  color: var(--secondary);
}

main {
  padding: 32px;
}

.page {
  display: none;
  max-width: 1180px;
  margin: 0 auto;
}

.page.active {
  display: block;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(320px, 0.7fr);
  gap: 24px;
  align-items: stretch;
}

.hero-copy,
.signal-panel,
.card,
.table-card,
.chat-panel,
.side-panel,
.result-panel,
.diagnose-form,
.lead-form,
.admin-content {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.06);
}

.hero-copy {
  padding: 36px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--primary);
  font-size: 13px;
  font-weight: 650;
}

h1 {
  max-width: 760px;
  margin: 0;
  font-size: 44px;
  line-height: 1.12;
  letter-spacing: 0;
}

h2 {
  margin: 0 0 12px;
  font-size: 22px;
}

.lead {
  max-width: 720px;
  margin: 18px 0 0;
  color: var(--subtle);
  font-size: 17px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 28px;
}

input,
textarea,
select {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  color: var(--text);
  padding: 10px 12px;
}

textarea {
  min-height: 108px;
  resize: vertical;
}

input:focus,
textarea:focus,
select:focus {
  outline: 2px solid rgba(15, 118, 110, 0.18);
  border-color: var(--primary);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 18px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
}

.button.primary {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
}

.button.primary:hover {
  background: var(--primary-dark);
}

.button.secondary {
  background: #fff;
  color: var(--secondary);
}

.signal-panel {
  padding: 24px;
}

.panel-header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 14px;
  font-weight: 650;
}

.status,
.badge {
  border-radius: 4px;
  background: var(--muted);
  color: var(--secondary);
  padding: 4px 8px;
  font-size: 12px;
}

.answer-steps {
  display: grid;
  gap: 10px;
  margin: 18px 0 0;
  padding-left: 22px;
}

.home-section {
  margin-top: 24px;
}

.section-title.compact {
  margin-bottom: 14px;
}

.intro-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.intro-grid h3 {
  margin: 0 0 8px;
  font-size: 18px;
}

.intro-grid p {
  color: var(--subtle);
  line-height: 1.7;
}

.intro-grid .button {
  margin-top: 8px;
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 12px;
  margin: 0;
}

.problem-card {
  min-height: 72px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  color: var(--secondary);
  cursor: pointer;
  font-weight: 650;
}

.problem-card:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.band {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  padding: 24px;
}

.band p {
  margin: 0;
  color: var(--subtle);
  line-height: 1.7;
}

.teacher-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin-top: 24px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  padding: 24px;
}

.teacher-panel p {
  max-width: 780px;
  margin: 0;
  color: var(--subtle);
  line-height: 1.7;
}

.workspace {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  gap: 20px;
}

.side-panel,
.chat-panel,
.diagnose-form,
.lead-form,
.admin-content {
  padding: 20px;
}

.side-panel {
  position: sticky;
  top: 86px;
  align-self: start;
  max-height: calc(100vh - 110px);
  overflow: auto;
}

.chat-panel {
  min-width: 0;
}

.sidebar-section + .sidebar-section {
  margin-top: 22px;
  border-top: 1px solid var(--border);
  padding-top: 18px;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.stat-card {
  display: grid;
  gap: 4px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--muted);
  padding: 12px;
}

.stat-card strong {
  color: var(--primary);
  font-size: 26px;
  line-height: 1;
}

.stat-card span,
.history-item small,
.empty-state {
  color: var(--subtle);
  font-size: 13px;
}

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

.sidebar-title-row h2 {
  margin: 0;
}

.stat-more-button {
  min-height: 32px;
  padding: 6px 10px;
  white-space: nowrap;
}

.history-list {
  display: grid;
  gap: 8px;
}

.history-item {
  display: grid;
  gap: 6px;
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  padding: 8px;
}

.history-question {
  display: grid;
  gap: 6px;
  width: 100%;
  border: 0;
  background: transparent;
  color: var(--text);
  cursor: pointer;
  padding: 4px;
  text-align: left;
}

.history-item:hover {
  border-color: var(--primary);
  background: #f0fdfa;
}

.history-question span {
  display: -webkit-box;
  overflow: hidden;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  line-height: 1.5;
}

.history-rename {
  justify-self: start;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: #fff;
  color: var(--subtle);
  cursor: pointer;
  padding: 4px 8px;
  font-size: 12px;
}

.history-rename:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.empty-state {
  margin: 0;
  border: 1px dashed var(--border);
  border-radius: 8px;
  padding: 12px;
  line-height: 1.6;
}

label {
  display: grid;
  gap: 6px;
  margin-bottom: 14px;
  color: var(--secondary);
  font-size: 14px;
  font-weight: 600;
}

.chat-log {
  display: grid;
  min-height: 360px;
  align-content: start;
  gap: 14px;
}

.message {
  max-width: 760px;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px;
  line-height: 1.65;
}

.message.user {
  justify-self: end;
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
}

.message.assistant {
  background: #fff;
}

.message ol {
  margin-bottom: 0;
}

.chat-compose {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
  margin-top: 16px;
}

.chat-compose textarea {
  min-height: 72px;
}

.section-title {
  margin-bottom: 22px;
}

.diagnose-form,
.lead-form {
  display: grid;
  gap: 12px;
}

.result-panel {
  margin-top: 18px;
  padding: 20px;
  line-height: 1.7;
}

.hidden {
  display: none;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th,
td {
  border-bottom: 1px solid var(--border);
  padding: 12px;
  text-align: left;
  vertical-align: top;
  font-size: 14px;
}

th {
  color: var(--secondary);
  background: var(--muted);
  font-weight: 650;
}

.membership-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-bottom: 18px;
}

.analytics-layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.analytics-panel {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  padding: 20px;
}

.analytics-panel.wide {
  grid-column: 1 / -1;
}

.ranking-list {
  display: grid;
  gap: 10px;
  margin-top: 14px;
}

.ranking-item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr) auto;
  gap: 10px;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
}

.ranking-item strong {
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border-radius: 6px;
  background: var(--muted);
  color: var(--primary);
}

.ranking-item span {
  overflow-wrap: anywhere;
}

.ranking-item em {
  color: var(--subtle);
  font-style: normal;
  font-size: 13px;
}

.keyword-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}

.keyword-chip {
  border: 1px solid var(--border);
  border-radius: 999px;
  background: #fff;
  color: var(--secondary);
  padding: 7px 10px;
  font-weight: 600;
}

.keyword-chip.level-2 {
  color: var(--primary);
  font-size: 16px;
}

.keyword-chip.level-3,
.keyword-chip.level-4 {
  border-color: rgba(15, 118, 110, 0.28);
  background: #f0fdfa;
  color: var(--primary-dark);
  font-size: 18px;
}

.ai-analysis {
  margin-top: 14px;
  color: var(--secondary);
  line-height: 1.75;
}

.ai-analysis p {
  margin: 0 0 10px;
}

.card {
  padding: 20px;
  line-height: 1.7;
}

.warning {
  border-color: #fed7aa;
  background: #fff7ed;
}

.form-status {
  color: var(--primary);
  font-weight: 650;
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: grid;
  place-items: center;
  background: rgba(15, 23, 42, 0.28);
  padding: 20px;
}

.modal-panel {
  width: min(520px, 100%);
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.1);
  padding: 22px;
}

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

.modal-heading p {
  margin: 8px 0 0;
  color: var(--subtle);
  line-height: 1.6;
}

.modal-close {
  border: 1px solid var(--border);
  border-radius: 6px;
  background: #fff;
  color: var(--secondary);
  cursor: pointer;
  padding: 6px 8px;
}

.register-form {
  display: grid;
  gap: 12px;
}

.login-panel {
  width: min(520px, 100%);
  margin: 48px auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.06);
  padding: 28px;
}

.login-panel h1 {
  font-size: 32px;
}

.login-panel p {
  color: var(--subtle);
  line-height: 1.7;
}

.login-form {
  display: grid;
  gap: 12px;
  margin-top: 18px;
}

.api-key-status {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 14px;
}

.api-key-status.ok {
  border-color: rgba(21, 128, 61, 0.35);
  background: #f0fdf4;
  color: #15803d;
}

.api-key-status.warn {
  border-color: #fed7aa;
  background: #fff7ed;
  color: var(--warning);
}

.admin-shell {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 18px;
}

.admin-nav {
  display: grid;
  align-content: start;
  gap: 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  padding: 12px;
}

.admin-nav button {
  border: 0;
  border-radius: 8px;
  background: transparent;
  padding: 10px 12px;
  text-align: left;
  cursor: pointer;
  color: var(--subtle);
}

.admin-nav button.active,
.admin-nav button:hover {
  background: var(--muted);
  color: var(--secondary);
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 14px 0;
}

.table-action {
  margin-right: 6px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: #fff;
  color: var(--secondary);
  padding: 6px 8px;
  cursor: pointer;
  font-size: 13px;
}

.table-action:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.page-heading-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

.page-heading-row p {
  margin: 8px 0 0;
  color: var(--subtle);
}

@media (max-width: 860px) {
  .site-header,
  .band {
    align-items: flex-start;
    flex-direction: column;
  }

  .account-menu {
    align-self: flex-end;
  }

  main {
    padding: 18px;
  }

  .hero,
  .workspace,
  .admin-shell,
  .analytics-layout,
  .membership-grid {
    grid-template-columns: 1fr;
  }

  .side-panel {
    position: static;
    max-height: none;
  }

  .problem-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .hero-actions,
  .chat-compose {
    grid-template-columns: 1fr;
  }


  .intro-grid {
    grid-template-columns: 1fr;
  }

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

  h1 {
    font-size: 34px;
  }
}