:root {
  --bg: #f5f6f8;
  --card: #ffffff;
  --text: #1c1e21;
  --muted: #6b7280;
  --border: #e5e7eb;
  --accent: #3b5bdb;
  --overdue: #d64545;
  --pending: #b8860b;
  --complete: #2f9e44;
  --turned-in: #3b5bdb;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --card: #1e2126;
    --text: #e8e9ec;
    --muted: #9aa0aa;
    --border: #2c2f36;
    --accent: #7c9bff;
    --overdue: #ff6b6b;
    --pending: #e0b34e;
    --complete: #5fd483;
    --turned-in: #7c9bff;
  }
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
}

header {
  position: sticky;
  top: 0;
  background: var(--bg);
  padding: 1.25rem 1.5rem 1rem;
  border-bottom: 1px solid var(--border);
  z-index: 10;
}

h1 {
  margin: 0 0 0.75rem;
  font-size: 1.5rem;
}

.controls {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  flex-wrap: wrap;
}

select {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.4rem 0.6rem;
  font-size: 0.9rem;
}

.updated-at {
  color: var(--muted);
  font-size: 0.8rem;
  margin-left: auto;
}

.nav-link {
  font-size: 0.85rem;
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
}

.nav-link:hover {
  text-decoration: underline;
}

.status-filters {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.3rem 0.7rem;
  margin: 0;
}

.status-filters legend {
  padding: 0 0.3rem;
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.status-filters label {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.9rem;
  white-space: nowrap;
  cursor: pointer;
}

.layout {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.5rem;
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 1.5rem;
  align-items: start;
}

@media (max-width: 800px) {
  .layout {
    grid-template-columns: 1fr;
  }
}

.classes-column {
  position: sticky;
  top: 5.5rem;
}

.classes-column h2 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  margin: 0 0 0.75rem;
}

.loading, .empty {
  color: var(--muted);
  padding: 2rem 0;
  text-align: center;
}

.group {
  margin-bottom: 2rem;
}

.group h2 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  margin: 0 0 0.75rem;
}

.assignment {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 0.6rem;
  overflow: hidden;
}

.assignment-header {
  padding: 0.9rem 1.1rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
  cursor: pointer;
}

.assignment-header:hover {
  background: color-mix(in srgb, var(--accent) 6%, transparent);
}

.assignment-main {
  min-width: 0;
}

.assignment-title {
  font-weight: 600;
  margin: 0 0 0.2rem;
}

.assignment-meta {
  color: var(--muted);
  font-size: 0.85rem;
}

.assignment-child {
  font-weight: 500;
  color: var(--text);
}

.badge {
  flex-shrink: 0;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  white-space: nowrap;
}

.badge-pending { background: color-mix(in srgb, var(--pending) 18%, transparent); color: var(--pending); }
.badge-complete { background: color-mix(in srgb, var(--complete) 18%, transparent); color: var(--complete); }
.badge-turnedin { background: color-mix(in srgb, var(--turned-in) 18%, transparent); color: var(--turned-in); }
.badge-other { background: color-mix(in srgb, var(--muted) 18%, transparent); color: var(--muted); }

.group.overdue h2 { color: var(--overdue); }

.group.done {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px dashed var(--border);
}

.group.done .assignment {
  opacity: 0.75;
}

.assignment-notes {
  padding: 0 1.1rem 1rem;
  border-top: 1px solid var(--border);
  margin-top: -1px;
}

.assignment-notes-body {
  padding-top: 0.8rem;
  font-size: 0.9rem;
  color: var(--text);
  line-height: 1.5;
}

.assignment-notes-body :first-child { margin-top: 0; }
.assignment-notes-body :last-child { margin-bottom: 0; }

.assignment-notes-empty {
  padding-top: 0.8rem;
  font-size: 0.85rem;
  color: var(--muted);
  font-style: italic;
}

.expand-hint {
  font-size: 0.75rem;
  color: var(--muted);
  flex-shrink: 0;
  align-self: center;
}

/* Classes side panel */
.student-group {
  margin-bottom: 1.25rem;
}

.student-group-heading {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text);
  margin: 0 0 0.5rem;
}

.student-group-gpa {
  flex-shrink: 0;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  white-space: nowrap;
}

.student-group-classes {
  padding-left: 0.9rem;
  border-left: 2px solid var(--border);
}

.class-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 0.6rem;
  overflow: hidden;
}

.class-card-header {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 0.9rem;
  background: none;
  border: none;
  font: inherit;
  color: inherit;
  text-align: left;
  cursor: pointer;
}

.class-card-header:hover {
  background: color-mix(in srgb, var(--accent) 6%, transparent);
}

.class-card-name {
  font-weight: 600;
  font-size: 0.9rem;
}

.class-card-grade {
  flex-shrink: 0;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent);
  white-space: nowrap;
}

.class-card-assignments {
  padding: 0 0.7rem 0.7rem;
  border-top: 1px solid var(--border);
}

.class-card-assignments .assignment {
  margin-top: 0.6rem;
  margin-bottom: 0;
}

.class-card-empty {
  padding: 0.7rem 0.9rem;
  color: var(--muted);
  font-size: 0.8rem;
  font-style: italic;
}

/* History page */
.layout-single {
  max-width: 760px;
  margin: 0 auto;
  padding: 1.5rem;
}

.change-event {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.9rem 1.1rem;
  margin-bottom: 0.6rem;
  border-left: 3px solid var(--muted);
}

.change-event-created {
  border-left-color: var(--complete);
}

.change-event-updated {
  border-left-color: var(--accent);
}

.change-event-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
}

.change-event-title {
  font-weight: 600;
}

.change-event-when {
  flex-shrink: 0;
  color: var(--muted);
  font-size: 0.8rem;
  white-space: nowrap;
}

.change-event-meta {
  margin: 0.2rem 0 0.5rem;
  color: var(--muted);
  font-size: 0.85rem;
}

.change-event-summary {
  margin: 0;
  font-size: 0.9rem;
}

.change-fields {
  margin: 0;
  padding-left: 1.1rem;
  font-size: 0.9rem;
}

.change-fields li {
  margin-bottom: 0.15rem;
}

/* Login, signup, and account forms */

.auth-layout {
  max-width: 440px;
  margin: 0 auto;
  padding: 3rem 1rem;
}

.auth-layout h1 {
  text-align: center;
  margin-bottom: 1.5rem;
}

.account-layout {
  max-width: 560px;
  display: grid;
  gap: 1.25rem;
}

.card-form {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
}

.card-form h2 {
  margin: 0;
  font-size: 1.1rem;
}

.card-form fieldset {
  border: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
}

.card-form legend {
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-bottom: 0.6rem;
}

.card-form label {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  font-size: 0.9rem;
}

.card-form input {
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.5rem 0.6rem;
  font-size: 1rem;
}

.card-form input:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
}

.card-form button {
  align-self: flex-start;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 0.55rem 1rem;
  font-size: 0.95rem;
  cursor: pointer;
}

.card-form button:disabled {
  opacity: 0.6;
  cursor: default;
}

.form-hint {
  margin: 0;
  color: var(--muted);
  font-size: 0.8rem;
}

.form-error {
  margin: 0;
  color: var(--overdue);
  font-size: 0.9rem;
}

.form-success {
  margin: 0;
  color: var(--complete);
  font-size: 0.9rem;
}

.form-switch {
  margin: 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.form-switch a, .empty a {
  color: var(--accent);
}

.account-name {
  color: var(--muted);
  font-size: 0.85rem;
  margin-left: auto;
}

.sync-status {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.35rem 1rem;
  margin: 0;
  font-size: 0.9rem;
}

.sync-status dt {
  color: var(--muted);
}

.sync-status dd {
  margin: 0;
}