:root {
  --font-heading: "Sora", "Segoe UI", system-ui, -apple-system, sans-serif;
  --font-body: "IBM Plex Sans", "Segoe UI", system-ui, -apple-system, sans-serif;
  --color-ink-900: #0f172a;
  --color-ink-700: #1f2937;
  --color-ink-500: #475569;
  --color-ink-300: #cbd5e1;
  --color-ink-200: #e2e8f0;
  --color-surface: #ffffff;
  --color-surface-muted: #f5f7fb;
  --color-accent: #2563eb;
  --color-accent-strong: #1e40af;
  --shadow-sm: 0 8px 20px rgba(15, 23, 42, 0.08);
  --shadow-md: 0 14px 40px rgba(15, 23, 42, 0.12);
  --shadow-lg: 0 18px 60px rgba(15, 23, 42, 0.14);
  --radius-s: 8px;
  --radius-m: 12px;
  --radius-l: 16px;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-7: 32px;
  --space-8: 40px;
  --space-9: 48px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--color-ink-900);
  background: linear-gradient(180deg, #f7f9fc 0%, #eef2f7 100%);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  margin: 0 0 var(--space-3);
  color: var(--color-ink-900);
  line-height: 1.2;
}

p {
  margin: 0 0 var(--space-3);
  color: var(--color-ink-700);
  line-height: 1.6;
}

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

.container {
  width: min(1180px, 92vw);
  margin: 0 auto;
}

.content {
  padding: var(--space-7) 0 var(--space-8);
}

.page-shell {
  min-height: 100vh;
}

.topbar {
  background: #0d152a;
  color: #f8fafc;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  position: sticky;
  top: 0;
  z-index: 20;
}

.topbar__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-3) 0;
}

.brand-group {
  display: grid;
  gap: var(--space-1);
}

.brand {
  font-weight: 700;
  letter-spacing: 0.4px;
  color: #f8fafc;
  font-size: 18px;
}

.eyebrow {
  margin: 0;
  font-size: 13px;
  color: rgba(248, 250, 252, 0.7);
  letter-spacing: 0.2px;
}

.topbar__actions {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  flex-wrap: wrap;
  justify-content: flex-end;
}

.user-area {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.user-name {
  font-weight: 500;
  color: #e2e8f0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-m);
  border: 1px solid var(--color-ink-200);
  background: var(--color-surface);
  color: var(--color-ink-900);
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  line-height: 1.2;
  min-height: 36px;
  transition: transform 120ms ease, box-shadow 140ms ease, background 160ms ease, border-color 160ms ease;
  box-shadow: var(--shadow-sm);
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn:active {
  transform: translateY(0);
}

.btn.primary {
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  border-color: #1d4ed8;
  color: #f8fafc;
  box-shadow: 0 10px 30px rgba(37, 99, 235, 0.35);
}

.btn.ghost {
  background: rgba(248, 250, 252, 0.05);
  color: #e2e8f0;
  border-color: rgba(226, 232, 240, 0.2);
  box-shadow: none;
}

.btn.small {
  padding: var(--space-1) var(--space-2);
  font-size: 13px;
  min-height: 32px;
}

.btn.tiny {
  padding: 2px var(--space-2);
  font-size: 12px;
  border-radius: var(--radius-s);
  min-height: 28px;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-2);
  border-radius: 999px;
  font-size: 12px;
  background: #e8eefc;
  color: var(--color-ink-700);
  border: 1px solid #d5ddf4;
}

.pill.soft {
  background: #f2f5fb;
  border-color: #e1e7f2;
}

.pill.link {
  background: #e8f1ff;
  color: var(--color-ink-900);
  text-decoration: none;
}

section + section {
  margin-top: var(--space-7);
}

.hero {
  background: var(--color-surface);
  padding: var(--space-8);
  border-radius: var(--radius-l);
  box-shadow: var(--shadow-md);
  display: grid;
  gap: var(--space-4);
  align-items: center;
}

.hero h1 {
  font-size: 32px;
}

.hero .lede {
  font-size: 16px;
  color: var(--color-ink-700);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
}

.hero-meta {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.muted {
  color: var(--color-ink-500);
  font-size: 14px;
  margin: 0;
}

.panel,
.card {
  background: var(--color-surface);
  border-radius: var(--radius-l);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-ink-200);
}

.panel h3,
.card h3 {
  margin-bottom: var(--space-2);
}

.doc-list {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
}

.doc-list.compact {
  grid-template-columns: 1fr;
}

.doc-card {
  background: var(--color-surface);
  border: 1px solid var(--color-ink-200);
  border-radius: var(--radius-m);
  padding: var(--space-4);
  box-shadow: 0 1px 6px rgba(15, 23, 42, 0.08);
  display: grid;
  gap: var(--space-2);
}

.doc-card h3 {
  margin: 0;
  font-size: 18px;
}

.doc-row {
  display: flex;
  justify-content: space-between;
  gap: var(--space-3);
  align-items: center;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-ink-200);
  border-radius: var(--radius-m);
  background: var(--color-surface-muted);
}

.doc-row > div {
  min-width: 0;
}

.classes-page {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.header-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-4);
}

.class-grid {
  display: grid;
  gap: var(--space-4);
  grid-template-columns: repeat(auto-fit, minmax(680px, 1fr));
}

.class-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  border-radius: var(--radius-l);
  border: 1px solid var(--color-ink-200);
  padding: var(--space-5);
  box-shadow: 0 6px 20px rgba(15, 23, 42, 0.08);
}

body.classes-page .container {
  width: min(1500px, 95vw);
}

.class-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.class-name {
  font-size: 18px;
  font-weight: 700;
}

.class-documents {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  border: 1px dashed var(--color-ink-200);
  padding: var(--space-4);
  border-radius: var(--radius-m);
  background: #f9fbff;
}

.student-chips {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.inline-form {
  display: flex;
  gap: var(--space-3);
  align-items: center;
  flex-wrap: wrap;
}

.inline-form input,
.inline-form select {
  padding: var(--space-2) var(--space-2);
  border-radius: var(--radius-m);
  border: 1px solid var(--color-ink-200);
  background: var(--color-surface);
  min-width: 240px;
  font-size: 14px;
}

.inline-form label {
  font-weight: 500;
  color: var(--color-ink-700);
}

.inline-form.upload input[type="file"] {
  min-width: 0;
}

.text-truncate {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-path {
  max-width: 100%;
}

.doc-card h3,
.doc-card p,
.doc-row span,
.doc-row .muted {
  overflow: hidden;
  text-overflow: ellipsis;
}

.data-card {
  background: var(--color-surface);
  border: 1px solid var(--color-ink-200);
  border-radius: var(--radius-l);
  padding: var(--space-5);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  width: 100%;
  max-width: 100%;
}

.data-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  align-items: center;
  justify-content: space-between;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.data-table thead {
  background: #f8fafc;
}

.data-table th,
.data-table td {
  padding: var(--space-2) var(--space-3);
  text-align: left;
  border-bottom: 1px solid var(--color-ink-200);
  vertical-align: middle;
}

.data-table th {
  font-weight: 700;
  color: var(--color-ink-700);
  white-space: nowrap;
}

.data-table td .pill {
  margin-right: var(--space-1);
}

.data-table .actions {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  align-items: center;
  width: 100%;
}

.table-filter {
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-m);
  border: 1px solid var(--color-ink-200);
  min-width: 200px;
}

.data-table tbody tr:nth-child(even) {
  background: #f8fafc;
}

.assign-form {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
  width: 100%;
}

.assign-form select {
  min-width: 140px;
}

.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.chip-input {
  position: relative;
  cursor: pointer;
}

.chip-input input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.chip-input .pill {
  transition: background 120ms ease, color 120ms ease, border-color 120ms ease, box-shadow 120ms ease;
}

.chip-input input:checked + .pill {
  background: #e0f2fe;
  border-color: #bfdbfe;
  color: var(--color-ink-900);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.25);
}

.invite-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.invite-row {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3);
  border-radius: var(--radius-m);
  border: 1px solid var(--color-ink-200);
  background: var(--color-surface-muted);
  flex-wrap: wrap;
}

.invite-url {
  font-family: "Consolas", "SFMono-Regular", Menlo, monospace;
  font-size: 12px;
  color: var(--color-ink-900);
  word-break: break-all;
}

.doc-accordion {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.accordion-section {
  border: 1px solid var(--color-ink-200);
  border-radius: var(--radius-m);
  background: var(--color-surface);
  box-shadow: var(--shadow-sm);
}

.accordion-toggle {
  width: 100%;
  text-align: left;
  background: transparent;
  border: none;
  padding: var(--space-3);
  font-weight: 700;
  font-size: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.accordion-body {
  display: none;
  padding: var(--space-3);
  border-top: 1px solid var(--color-ink-200);
}

.accordion-body.open {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.35);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  padding: var(--space-4);
}

.modal-backdrop.open {
  display: flex;
}

.modal-card {
  background: var(--color-surface);
  border-radius: var(--radius-l);
  border: 1px solid var(--color-ink-200);
  box-shadow: var(--shadow-lg);
  width: min(520px, 96vw);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: var(--space-4);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-2);
  font-weight: 700;
  font-size: 18px;
}

.modal-body {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.modal-body input[type="file"],
.modal-body input[type="text"] {
  width: 100%;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-m);
  border: 1px solid var(--color-ink-200);
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-2);
}

.viewer-layout {
  position: relative;
}

.viewer-panel {
  background: transparent;
  border-radius: 0;
  padding: 0;
  overflow: auto;
  box-shadow: none;
  height: calc(100vh - 150px);
  backdrop-filter: none;
}

.viewer-controls {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  gap: 6px;
  margin: 0 auto var(--space-3);
  padding: 4px 8px;
  border: 1px solid var(--color-ink-200);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: var(--shadow-sm);
  justify-content: center;
  width: 100%;
  max-width: 100vw;
}

.viewer-controls .page-row,
.viewer-controls .zoom-row,
.viewer-controls .nav-swatches {
  padding: 0;
  border: none;
  background: transparent;
  gap: 6px;
}

.viewer-controls .nav-swatches {
  align-items: center;
}

.viewer-controls .btn {
  padding: 2px 7px;
  font-size: 11px;
  min-height: 22px;
  border-radius: var(--radius-s);
}

.viewer-controls #page-select {
  padding: 2px 7px;
  font-size: 11px;
  min-width: 100px;
}

.viewer-controls #zoom-label {
  font-size: 11px;
  min-width: 52px;
  padding: 2px 7px;
}

.viewer-controls .tool-row .btn {
  min-height: 22px;
  padding: 2px 9px;
  font-size: 11px;
}

.pdf-viewer {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  align-items: center;
  padding-bottom: var(--space-8);
}

.pdf-page {
  position: relative;
  padding-right: 120px;
  background: var(--color-surface);
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.12);
  border-radius: var(--radius-m);
  margin: var(--space-3) 0;
  scroll-margin-top: var(--space-4);
}

.annotation-layer {
  position: absolute;
  left: 0;
  top: 0;
  pointer-events: auto;
  z-index: 1;
}

.note-layer {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 2;
  pointer-events: auto;
}

.note-layer .note-button,
.note-layer .note-card,
.note-layer .note-editor {
  pointer-events: auto;
  position: absolute;
}

.note-button {
  right: 8px;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 1px solid var(--note-btn-border, #f59e0b);
  background: var(--note-btn-bg, #fff7d6);
  color: var(--note-btn-text, #c2410c);
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.15);
  z-index: 9999;
}

.note-card {
  right: 8px;
  min-width: 200px;
  max-width: 240px;
  background: #fff7d6;
  border: 1px solid #f59e0b;
  border-radius: var(--radius-m);
  padding: var(--space-3);
  color: #1f2937;
  font-size: 13px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.12);
}

.note-card .note-actions {
  margin-top: var(--space-2);
  display: flex;
  justify-content: flex-end;
  gap: var(--space-2);
}

.note-connector {
  stroke: #f59e0b;
  stroke-width: 2;
  fill: none;
  stroke-dasharray: 3 2;
}

.note-editor {
  width: 220px;
  padding: var(--space-3);
  background: var(--color-surface);
  border: 1px solid #e5e7eb;
  border-radius: var(--radius-m);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.12);
  z-index: 12000;
}

.note-editor textarea {
  width: 100%;
  min-height: 80px;
  resize: vertical;
  padding: var(--space-2);
  font-family: var(--font-body);
}

.note-editor .actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.note-actions .icon-btn {
  width: 28px;
  height: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-s);
  border: 1px solid rgba(15, 23, 42, 0.15);
  background: #f8fafc;
  color: var(--color-ink-900);
  cursor: pointer;
  padding: 0;
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.12);
  transition: background 120ms ease, box-shadow 120ms ease, transform 120ms ease;
}

.note-actions .icon-btn:hover {
  background: #e2e8f0;
  box-shadow: 0 4px 10px rgba(15, 23, 42, 0.16);
  transform: translateY(-1px);
}

.note-actions .icon-btn.delete {
  color: #b91c1c;
  border-color: rgba(185, 28, 28, 0.2);
  background: #fef2f2;
  box-shadow: 0 2px 6px rgba(185, 28, 28, 0.15);
}

.note-actions .icon-btn.delete:hover {
  background: #fee2e2;
  box-shadow: 0 4px 12px rgba(185, 28, 28, 0.2);
}

.swatches {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.swatch-row {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.swatch {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 2px solid rgba(15, 23, 42, 0.08);
  background: radial-gradient(circle at 30% 30%, #fff, var(--swatch-color, #eee));
  cursor: pointer;
  box-shadow: inset 0 1px 2px rgba(255, 255, 255, 0.6), 0 8px 16px rgba(15, 23, 42, 0.12);
  transition: transform 120ms ease, box-shadow 120ms ease, border-color 120ms ease;
}

.swatch.selected {
  border-color: var(--color-accent);
  transform: translateY(-1px);
  box-shadow: 0 0 0 3px #fff, 0 12px 24px rgba(37, 99, 235, 0.18);
}

.page-row,
.zoom-row {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1);
  border-radius: var(--radius-s);
  border: 1px solid rgba(226, 232, 240, 0.3);
  background: rgba(255, 255, 255, 0.04);
}

.nav-swatches {
  display: flex;
  gap: var(--space-2);
  align-items: center;
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  justify-content: flex-start;
}

.nav-controls .doc-title {
  font-weight: 700;
  color: #e2e8f0;
}

.nav-controls .btn {
  padding: var(--space-1) var(--space-2);
  font-size: 12px;
  min-height: 28px;
  border-radius: var(--radius-s);
  box-shadow: none;
}

#page-select {
  padding: var(--space-1);
  border-radius: var(--radius-s);
  border: 1px solid #cbd5e1;
  background: #fff;
  box-shadow: inset 0 1px 2px rgba(15, 23, 42, 0.06);
  font-size: 12px;
  min-width: 100px;
}

.zoom-row span#zoom-label {
  padding: var(--space-1) var(--space-2);
  min-width: 58px;
  text-align: center;
  border-radius: var(--radius-s);
  background: rgba(15, 23, 42, 0.06);
  font-weight: 600;
  font-size: 13px;
  color: #0f172a;
}

.context-menu {
  position: absolute;
  z-index: 9999;
  background: #0f172a;
  color: #e2e8f0;
  border-radius: var(--radius-m);
  box-shadow: 0 12px 32px rgba(15, 23, 42, 0.35);
  min-width: 176px;
  padding: var(--space-1) 0;
  font-size: 13px;
}

.context-menu button {
  width: 100%;
  padding: var(--space-2) var(--space-3);
  background: transparent;
  border: none;
  color: inherit;
  text-align: left;
  cursor: pointer;
}

.context-menu button:hover {
  background: rgba(255, 255, 255, 0.08);
}

iframe {
  border-radius: var(--radius-l);
  border: 1px solid var(--color-ink-200);
  box-shadow: var(--shadow-md);
}

body.viewer-page .content {
  padding-top: var(--space-5);
  padding-bottom: var(--space-4);
  height: calc(100vh - 64px);
  overflow: hidden;
}

body.viewer-page .container {
  width: 100vw;
  max-width: 100vw;
  padding-left: var(--space-5);
  padding-right: var(--space-5);
  margin: 0 auto;
}

body.viewer-page .viewer-layout {
  height: 100%;
  display: flex;
  flex-direction: column;
}

body.viewer-page .viewer-panel {
  flex: 1;
}

@media (max-width: 900px) {
  .topbar__row,
  .header-row {
    flex-direction: column;
    align-items: flex-start;
  }

  .hero {
    padding: var(--space-6);
  }

  .viewer-panel {
    height: auto;
  }

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

@media (max-width: 1100px) {
  .topbar__row {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
  }

  .topbar__actions {
    width: 100%;
    justify-content: flex-start;
    gap: var(--space-2);
  }

  .nav-controls {
    width: 100%;
    flex-wrap: nowrap;
    overflow-x: auto;
    gap: var(--space-2);
    padding: var(--space-1) 0;
  }

  .nav-controls > * {
    flex: 0 0 auto;
  }

  .nav-controls .doc-title {
    min-width: 160px;
  }

  .user-area {
    width: 100%;
    justify-content: flex-start;
    flex-wrap: wrap;
    gap: var(--space-2);
  }
}