:root {
  --bg: #f7f9fc;
  --surface: #ffffff;
  --text: #1f2933;
  --muted: #52606d;
  --muted-surface: #d6dce260;
  --primary: #0b63ce;
  --primary-hover: #094ea3;
  --danger-bg: #ffe3e3;
  --danger-text: #7d1a1a;
  --success-bg: #def7e5;
  --success-text: #14532d;
  --border: #d9e2ec;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(180deg, #eef4ff 0%, var(--bg) 100%);
  color: var(--text);
  line-height: 1.5;
}

a {
  color: var(--primary);
}

a:hover {
  color: var(--primary-hover);
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 3px solid #1c7ed6;
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  left: 0;
  top: -48px;
  background: #111827;
  color: #ffffff;
  padding: 0.75rem 1rem;
  z-index: 1000;
}

.skip-link:focus {
  top: 0;
}

.site-header,
main,
.site-footer {
  max-width: 960px;
  margin: 0 auto;
  padding: 1rem;
}

nav {
  margin-bottom: 1rem;
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
}

nav ul {
  list-style: none;
  margin: 0;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  flex-direction: row;
}

.panel,
.card-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem;
  margin-bottom: 1rem;
}

.panel-muted {
  background: var(--muted-surface);
  border-radius: 1rem;
  padding: .75rem;
  margin-bottom: 1rem;
  border: 1px solid var(--border);
}

.card-list {
  list-style: none;
  padding: 0;
  margin: 1rem 0 0;
  display: grid;
  gap: 0.75rem;
}

.lez-form {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem;
  margin-bottom: 1rem;
}

.form-row {
  display: grid;
  gap: 0.35rem;
  margin-bottom: .5em;
}

.form-row button {
  max-width: fit-content;
}

label {
  font-weight: 600;
}

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

input,
select,
textarea {
  width: 100%;
  border: 1px solid #9aa5b1;
  border-radius: 8px;
  padding: 0.6rem 0.7rem;
  background: #ffffff;
}

textarea {
  resize: vertical;
}

button {
  border: none;
  border-radius: 8px;
  padding: 0.65rem 1rem;
  background: var(--primary);
  color: #ffffff;
  cursor: pointer;
}

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

.alert,
.success {
  border-radius: 8px;
  padding: 0.75rem 0.85rem;
  margin-bottom: 1rem;
}

.alert {
  background: var(--danger-bg);
  color: var(--danger-text);
}

.success {
  background: var(--success-bg);
  color: var(--success-text);
}

.site-footer {
  color: var(--muted);
  padding-bottom: 2rem;
}

.inline-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
  justify-content: space-between;
}

.inline-actions form {
  margin: 0;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
}

.button-link {
  display: inline-block;
  border-radius: 8px;
  border: 1px solid var(--primary);
  padding: 0.45rem 0.7rem;
  text-decoration: none;
}

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

.danger {
  background: #b42318;
}

.danger:hover {
  background: #8f1d14;
}

.muted {
  color: var(--muted);
}

.lesson-description-preview {
  margin-top: 0.55rem;
  margin-bottom: 0;
}

.lesson-description {
  white-space: pre-wrap;
}

.lesson-description:empty,
.lesson-description-preview:empty {
  display: none;
}

.order-controls {
  display: inline-flex;
  gap: 0.4rem;
  align-items: center;
}

.order-controls form {
  margin: 0;
}

.order-button {
  min-width: 44px;
  min-height: 44px;
  padding: 0.45rem 0.75rem;
}

.order-button:disabled {
  cursor: not-allowed;
  opacity: 0.6;
}

.sr-only {
  border: 0;
  clip: rect(0 0 0 0);
  height: 1px;
  margin: -1px;
  overflow: hidden;
  padding: 0;
  position: absolute;
  width: 1px;
 }

 .breadcrumb {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0;
  display: flex;
  justify-content: center;
  gap: 0.25rem;
  font-weight: 400;
}

.breadcrumb li {
  display: inline;
}

.breadcrumb li:not(:last-child)::after {
  content: " / ";
}

.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  text-decoration: underline;
}

.file-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.85rem;
}

.file-grid-item {
  margin: 0;
}

.file-grid-empty {
  grid-column: 1 / -1;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.8rem;
}

.file-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.8rem;
  text-decoration: none;
  min-height: 180px;
}

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

.file-card:focus-visible {
  outline: 3px solid #1c7ed6;
  outline-offset: 2px;
}

.file-icon,
.file-thumb {
  width: 100%;
  max-width: 120px;
  height: 90px;
  object-fit: contain;
}

.file-thumb {
  border: 1px solid var(--border);
  border-radius: 8px;
  object-fit: cover;
}

.file-name {
  font-weight: 600;
  text-align: center;
  word-break: break-word;
  margin-top: 1em;
}

.file-name:hover {
  text-decoration: underline;
}

@media (max-width: 640px) {
  .site-header,
  main,
  .site-footer {
    padding: 0.85rem;
  }
}