:root {
  color-scheme: light;
  --bg: #f6f7fb;
  --card: #ffffff;
  --text: #22253a;
  --muted: #70758c;
  --line: #dce0ea;
  --primary: #4f46e5;
  --primary-soft: #eef0ff;
  --danger: #c2410c;
  --shadow: 0 18px 45px rgba(35, 42, 70, 0.08);
  font-family: Inter, -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: linear-gradient(180deg, #f9faff 0%, var(--bg) 100%);
  color: var(--text);
}

button,
input,
textarea {
  font: inherit;
}

.shell {
  width: min(1280px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 28px 0 96px;
}

.shell-narrow {
  width: min(760px, calc(100vw - 32px));
}

.page-topbar {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 20px;
}

.page-topbar-title {
  margin: 0;
  font-size: clamp(1.5rem, 2vw, 2.1rem);
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.user-pill,
.status-pill {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 8px 12px;
  background: #eef2ff;
  color: var(--primary);
  font-weight: 700;
  font-size: 0.9rem;
}

.status-pill.inactive {
  background: #fff0eb;
  color: var(--danger);
}

.auth-card {
  margin-top: 24px;
}

.hero-card,
.page-header,
.topic-create-card,
.empty-card,
.topic-card,
.recorder-panel,
.sidebar-card {
  background: var(--card);
  border: 1px solid rgba(220, 224, 234, 0.9);
  border-radius: 22px;
  box-shadow: var(--shadow);
}

.hero-card,
.empty-card {
  padding: 28px;
}

.page-header,
.topic-create-card,
.topic-card,
.sidebar-card {
  padding: 20px;
}

.app-layout {
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 20px;
  align-items: start;
}

.app-layout.single-column {
  grid-template-columns: 1fr;
}

.sidebar {
  position: sticky;
  top: 18px;
  display: grid;
  gap: 16px;
}

.content-area {
  min-width: 0;
}

.mobile-only {
  display: none !important;
}

.sidebar-brand,
.sidebar-card {
  display: grid;
  gap: 12px;
}

.sidebar-title,
.sidebar-section-title {
  margin: 0;
}

.sidebar-title {
  font-size: 1.3rem;
}

.sidebar-section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
}

.compact-button {
  min-height: 34px;
  padding: 0 12px;
  border-radius: 12px;
}

.assignment-list {
  display: grid;
  gap: 10px;
  max-height: calc(100vh - 220px);
  overflow: auto;
}

.assignment-link {
  display: grid;
  gap: 6px;
  padding: 12px 14px;
  text-decoration: none;
  border-radius: 16px;
  border: 1px solid #e7eaf3;
  background: #fbfcff;
  color: inherit;
  transition: border-color 0.16s ease, transform 0.16s ease, background 0.16s ease;
}

.assignment-link:hover {
  transform: translateY(-1px);
  border-color: #cfd5e7;
}

.assignment-link.active {
  border-color: rgba(79, 70, 229, 0.3);
  background: #f2f4ff;
}

.assignment-link-title {
  font-weight: 700;
  color: var(--text);
}

.assignment-link-meta {
  font-size: 0.86rem;
  color: var(--muted);
}

.page-header {
  display: grid;
  gap: 0;
  grid-template-columns: 1fr;
  margin-bottom: 18px;
}

.assignment-header-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  flex-wrap: wrap;
  padding-bottom: 18px;
}

.assignment-page-title {
  margin: 0;
  font-size: clamp(1.6rem, 2vw, 2.2rem);
  line-height: 1.2;
}

.assignment-header-section {
  display: grid;
  gap: 10px;
  padding-top: 18px;
  border-top: 1px solid #edf0f6;
}

.assignment-header-section + .assignment-header-section {
  margin-top: 18px;
}

.topic-create-card {
  margin-bottom: 18px;
}

.hero-card h1,
.page-header h1,
.empty-card h1 {
  margin: 0 0 10px;
  font-size: clamp(1.8rem, 2.3vw, 2.5rem);
  line-height: 1.15;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--primary);
  font-weight: 700;
  letter-spacing: 0.04em;
  font-size: 0.88rem;
}

.hero-text,
.subtle-text,
.empty-card p {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.stack-form,
.topic-create-form,
.share-box,
.grow {
  display: grid;
  gap: 10px;
}

.topic-create-form {
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
}

.field-label {
  font-size: 0.92rem;
  font-weight: 700;
  color: #3b4158;
}

.text-input,
.select-input,
.block-textarea {
  width: 100%;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 14px;
  padding: 12px 14px;
  color: var(--text);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.text-input:focus,
.select-input:focus,
.block-textarea:focus {
  border-color: rgba(79, 70, 229, 0.55);
  outline: none;
  box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.12);
}

.select-input {
  min-height: 46px;
}

.block-textarea {
  min-height: 104px;
  resize: vertical;
  line-height: 1.6;
}

.readonly-text {
  min-height: 52px;
  line-height: 1.7;
  color: var(--text);
  white-space: normal;
}

.primary-button,
.secondary-button,
.ghost-button,
.action-button,
.as-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 16px;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  font-weight: 700;
  text-decoration: none;
  transition: transform 0.14s ease, box-shadow 0.14s ease, opacity 0.14s ease;
}

.primary-button:hover,
.secondary-button:hover,
.ghost-button:hover,
.action-button:hover,
.as-link:hover {
  transform: translateY(-1px);
}

.primary-button {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 10px 24px rgba(79, 70, 229, 0.25);
}

.secondary-button {
  background: var(--primary-soft);
  color: var(--primary);
}

.ghost-button {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--line);
}

.action-button {
  min-height: 36px;
  padding: 0 14px;
  background: #f5f7ff;
  color: #394065;
  font-size: 0.92rem;
}

.danger-button {
  background: #fff5f2;
  color: #c2410c;
}

.feedback-text {
  min-height: 1.25rem;
  margin: 0;
  color: var(--danger);
  font-size: 0.92rem;
}

.topics-container {
  display: grid;
  gap: 18px;
}

.topic-card {
  display: grid;
  gap: 16px;
}

.topic-card-header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: flex-start;
}

.toolbar-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.assignment-toolbar {
  margin-top: 0;
}

.topic-title {
  margin: 0;
  font-size: 1.18rem;
}

.topic-meta {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.block-list {
  display: grid;
  gap: 12px;
}

.block-row {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
}

.block-card {
  border: 1px solid #edf0f6;
  background: #fcfcfe;
  border-radius: 18px;
  padding: 14px;
  display: grid;
  gap: 12px;
}

.block-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
}

.badge {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 4px 10px;
  background: #eef2ff;
  color: var(--primary);
  font-size: 0.86rem;
  font-weight: 700;
}

.audio-card {
  gap: 10px;
  align-content: start;
}

.audio-player {
  width: 100%;
  display: block;
  height: 54px;
  max-height: 54px;
}

.audio-name {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.insert-control {
  position: relative;
  display: flex;
  justify-content: center;
  padding-top: 12px;
}

.insert-control.standalone {
  padding-top: 0;
}

.insert-trigger {
  width: 28px;
  height: 28px;
  border: 1px solid #d9def0;
  border-radius: 999px;
  background: #fff;
  color: var(--muted);
  font-size: 1.1rem;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 8px 18px rgba(35, 42, 70, 0.08);
}

.insert-trigger:hover {
  color: var(--primary);
  border-color: #c9d0ea;
}

.insert-menu {
  position: absolute;
  top: 2px;
  left: 38px;
  min-width: 134px;
  padding: 8px;
  border-radius: 14px;
  border: 1px solid #e3e8f4;
  background: #fff;
  box-shadow: 0 18px 34px rgba(35, 42, 70, 0.14);
  display: none;
  z-index: 12;
}

.insert-control.open .insert-menu {
  display: grid;
  gap: 6px;
}

.insert-menu-item {
  min-height: 34px;
  padding: 0 10px;
  border: none;
  border-radius: 10px;
  background: #f5f7ff;
  color: #394065;
  text-align: left;
  cursor: pointer;
  font-weight: 600;
}

.insert-menu-item:hover {
  background: #ecefff;
}

.empty-insert-wrap {
  display: flex;
  justify-content: flex-start;
}

.share-row {
  display: flex;
  gap: 10px;
}

.share-row-split .select-input {
  flex: 1;
  min-width: 0;
}

.share-row-split .secondary-button {
  flex-shrink: 0;
}

.share-grant-list {
  display: grid;
  gap: 10px;
}

.share-grant-item,
.user-card {
  border: 1px solid #edf0f6;
  border-radius: 16px;
  background: #fbfcff;
  padding: 14px;
  display: grid;
  gap: 12px;
}

.share-grant-meta,
.user-card-meta {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.share-grant-name,
.user-card-name {
  margin: 0;
  font-weight: 700;
}

.share-grant-time {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.user-list {
  display: grid;
  gap: 12px;
}

.user-card-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.user-card-field {
  display: grid;
  gap: 8px;
}

.user-card-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.role-help {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.empty-card.compact {
  padding: 18px;
}

.empty-state {
  border: 1px dashed var(--line);
  background: #fafbff;
  border-radius: 18px;
  padding: 20px;
  text-align: center;
  color: var(--muted);
}

.recorder-panel {
  position: sticky;
  bottom: 12px;
  margin-top: 18px;
  padding: 14px 18px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
}

.recorder-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.recording-timer {
  min-width: 72px;
  font-weight: 700;
  color: var(--primary);
}

.hidden {
  display: none !important;
}

@media (max-width: 860px) {
  .app-layout,
  .page-header,
  .topic-create-form,
  .user-card-grid {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }

  body[data-page="assignment"]:not(.mobile-sidebar-mode) .sidebar {
    display: none;
  }

  body[data-page="assignment"].mobile-sidebar-mode .content-area {
    display: none;
  }

  .mobile-only {
    display: inline-flex !important;
  }

  .mobile-toolbar {
    margin-bottom: 12px;
  }

  .share-row {
    flex-direction: column;
  }
}

@media (max-width: 640px) {
  .shell,
  .shell-narrow {
    width: min(100vw - 20px, 100%);
    padding-top: 20px;
    padding-bottom: 80px;
  }

  .hero-card,
  .empty-card,
  .page-header,
  .topic-create-card,
  .topic-card {
    padding: 16px;
    border-radius: 18px;
  }

  .topic-card-header,
  .recorder-panel,
  .page-topbar {
    flex-direction: column;
    align-items: stretch;
  }

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

  .insert-control {
    justify-content: flex-start;
    padding-top: 0;
  }

  .insert-menu {
    position: static;
    margin-top: 8px;
    min-width: 100%;
  }

  .block-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .primary-button,
  .secondary-button,
  .ghost-button,
  .select-input {
    width: 100%;
  }

  .assignment-toolbar {
    width: 100%;
  }

  .assignment-header-top {
    flex-direction: column;
    align-items: stretch;
  }

  .topbar-actions {
    justify-content: stretch;
  }
}