/* ==========================================================================
   The lesson page: the intro, the progress track, the lesson card, the
   editor and result, and the closing screen. The editor reuses the spell
   book classes from home.css (.vd-editor, .vd-code, .vd-hl) by name, so the
   few rules it needs are repeated here rather than loading the whole file.
   ========================================================================== */

/* ---------------------------------------------------------------- intro */

.ln-intro {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.ln-vudu {
  flex: none;
  width: 8.75rem;
  height: auto;
  filter: drop-shadow(0 10px 18px oklch(0.3 0.2 288 / 0.25));
}

@media (max-width: 47.99rem) {
  .ln-vudu {
    width: 5rem;
    align-self: flex-start;
  }
}

.ln-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.ln-facts li {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: var(--m-radius-full);
  background: color-mix(in oklab, var(--surface) 80%, transparent);
  color: var(--muted-foreground);
  font-size: 0.8125rem;
}

.ln-facts .vd-icon {
  width: 0.95rem;
  height: 0.95rem;
  color: var(--primary);
}

/* ------------------------------------------------------- progress track */

.ln-track {
  position: relative;
  margin: 0.5rem 0 1.5rem;
}

.ln-bar {
  position: absolute;
  left: 1.1rem;
  right: 1.1rem;
  top: 50%;
  height: 4px;
  margin-top: -2px;
  border-radius: var(--m-radius-full);
  background: color-mix(in oklab, var(--foreground) 9%, transparent);
  overflow: hidden;
}

.ln-bar i {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--magenta), var(--amber));
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 600ms var(--m-ease-spring, cubic-bezier(0.3, 1.3, 0.5, 1));
}

.ln-dots {
  position: relative;
  display: flex;
  justify-content: space-between;
}

.ln-dot {
  position: relative;
  display: grid;
  place-items: center;
  width: 2.25rem;
  height: 2.25rem;
  border: 2px solid var(--border);
  border-radius: var(--m-radius-full);
  background: var(--surface);
  color: var(--muted-foreground);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 200ms, border-color 200ms, background-color 200ms, color 200ms;
}

.ln-dot:hover {
  transform: translateY(-2px);
  border-color: color-mix(in oklab, var(--primary) 55%, var(--border));
}

.ln-dot .vd-icon {
  display: none;
  width: 1rem;
  height: 1rem;
}

.ln-dot.is-done {
  border-color: var(--primary);
  background: var(--primary);
  color: var(--primary-foreground);
}

.ln-dot.is-done span {
  display: none;
}

.ln-dot.is-done .vd-icon {
  display: block;
}

.ln-dot[aria-current='step'] {
  border-color: var(--primary);
  box-shadow: 0 0 0 5px color-mix(in oklab, var(--primary) 18%, transparent);
  color: var(--primary);
}

.ln-dot.is-done[aria-current='step'] {
  color: var(--primary-foreground);
}

@media (max-width: 30rem) {
  .ln-dot {
    width: 1.9rem;
    height: 1.9rem;
    font-size: 0.75rem;
  }
}

/* --------------------------------------------------------------- lesson */

.ln-lesson {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: minmax(0, 1fr);
}

@media (min-width: 64rem) {
  .ln-lesson {
    grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
    align-items: start;
  }
}

.ln-lesson[hidden],
.ln-end[hidden] {
  display: none;
}

.ln-card {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding: 1.5rem;
  border: 1px solid var(--border);
  border-radius: var(--m-radius-2xl);
  background: var(--surface);
  box-shadow: var(--m-shadow-md);
}

@media (min-width: 64rem) {
  .ln-card {
    position: sticky;
    top: 5rem;
    min-height: 34rem;
  }
}

.ln-step {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--primary);
}

.ln-title {
  margin-top: -0.5rem;
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

.ln-body {
  color: var(--muted-foreground);
  line-height: 1.65;
}

.ln-card code,
.ln-hint code {
  padding: 0.1rem 0.4rem;
  border-radius: var(--m-radius-sm);
  background: color-mix(in oklab, var(--primary) 11%, transparent);
  color: var(--foreground);
  font-family: var(--font-mono);
  font-size: 0.85em;
  white-space: nowrap;
}

/* The task: waiting is a dashed outline, passed turns green and pops. */
.ln-task {
  display: flex;
  gap: 0.875rem;
  padding: 1rem;
  border: 1.5px dashed color-mix(in oklab, var(--primary) 45%, var(--border));
  border-radius: var(--m-radius-xl);
  background: color-mix(in oklab, var(--primary) 5%, var(--surface));
  transition: background-color 300ms, border-color 300ms;
}

.ln-task-icon {
  display: grid;
  place-items: center;
  flex: none;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--m-radius-full);
  background: color-mix(in oklab, var(--primary) 14%, transparent);
  color: var(--primary);
  transition: background-color 300ms, color 300ms;
}

.ln-task-icon .vd-icon {
  width: 1.1rem;
  height: 1.1rem;
}

.ln-i-done,
.ln-task[data-state='passed'] .ln-i-wait {
  display: none;
}

.ln-task[data-state='passed'] .ln-i-done {
  display: block;
}

.ln-task-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--primary);
}

.ln-task-text {
  margin-top: 0.15rem;
  font-weight: 600;
  line-height: 1.5;
}

.ln-task-status {
  margin-top: 0.4rem;
  font-size: 0.8125rem;
  color: var(--muted-foreground);
}

.ln-task[data-state='passed'] {
  border-style: solid;
  border-color: color-mix(in oklab, var(--success) 55%, var(--border));
  background: color-mix(in oklab, var(--success) 10%, var(--surface));
}

.ln-task[data-state='passed'] .ln-task-icon {
  background: var(--success);
  color: var(--success-foreground, #fff);
}

.ln-task[data-state='passed'] .ln-task-label,
.ln-task[data-state='passed'] .ln-task-status {
  color: color-mix(in oklab, var(--success) 80%, var(--foreground));
}

.ln-task[data-state='waiting'] .ln-task-icon {
  animation: ln-breathe 2.4s ease-in-out infinite;
}

@keyframes ln-breathe {
  0%,
  100% {
    box-shadow: 0 0 0 0 color-mix(in oklab, var(--primary) 0%, transparent);
  }
  50% {
    box-shadow: 0 0 0 6px color-mix(in oklab, var(--primary) 14%, transparent);
  }
}

@keyframes ln-pop {
  0% {
    transform: scale(1);
  }
  35% {
    transform: scale(1.035);
  }
  100% {
    transform: scale(1);
  }
}

.ln-pop {
  animation: ln-pop 420ms cubic-bezier(0.3, 1.5, 0.5, 1);
}

.ln-help {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  margin: -0.25rem 0 0 -0.5rem;
}

.ln-help .vd-icon {
  width: 0.95rem;
  height: 0.95rem;
}

.ln-hint {
  padding: 0.75rem 1rem;
  border-left: 3px solid var(--amber);
  border-radius: var(--m-radius-md);
  background: color-mix(in oklab, var(--amber) 10%, var(--surface));
  font-size: 0.9rem;
}

.ln-hint code {
  white-space: pre-wrap;
}

.ln-nav {
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
  margin-top: auto;
  padding-top: 0.5rem;
}

.ln-flip {
  transform: scaleX(-1);
}

.ln-next-ready .vd-icon {
  animation: ln-nudge 1.2s ease-in-out infinite;
}

@keyframes ln-nudge {
  0%,
  100% {
    transform: translateX(0);
  }
  50% {
    transform: translateX(4px);
  }
}

/* Each step slides in, so the change of step reads as movement forward. */
@keyframes ln-enter {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.ln-enter {
  animation: ln-enter 360ms cubic-bezier(0.2, 0.8, 0.3, 1);
}

@keyframes ln-flash {
  0% {
    box-shadow: 0 0 0 0 oklch(0.8 0.15 68 / 0.7);
  }
  100% {
    box-shadow: 0 0 0 14px oklch(0.8 0.15 68 / 0);
  }
}

.ln-flash {
  animation: ln-flash 650ms ease-out;
}

/* ------------------------------------------------------- editor, result */

.ln-work {
  display: grid;
  gap: 1rem;
  min-width: 0;
}

.ln-pane {
  border: 1px solid var(--border);
  border-radius: var(--m-radius-2xl);
  overflow: hidden;
  background: var(--surface);
  box-shadow: var(--m-shadow-md);
}

.ln-pane-code {
  background: var(--vd-frame);
  color: var(--vd-frame-ink);
}

.ln-pane .vframe-bar {
  border-bottom: 1px solid var(--vd-frame-line);
}

.ln-pane-result .vframe-bar {
  background: var(--surface-2);
  border-bottom-color: var(--border);
}

.ln-live {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  align-self: center;
  padding-right: 0.75rem;
  color: var(--vd-frame-dim);
  font-size: 0.75rem;
}

.ln-live i {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: var(--success);
  animation: ln-breathe-dot 2s ease-in-out infinite;
}

@keyframes ln-breathe-dot {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.35;
  }
}

.vd-editor {
  display: flex;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.65;
  font-variant-ligatures: none;
}

.ln-editor {
  height: 15rem;
}

.vd-gutter {
  flex: none;
  width: 2.75rem;
  padding: 1rem 0.75rem 1rem 0;
  overflow: hidden;
  text-align: right;
  color: var(--vd-frame-dim);
  opacity: 0.7;
  user-select: none;
  white-space: pre;
}

.vd-code {
  position: relative;
  flex: 1;
  min-width: 0;
}

.vd-code .vd-hl,
.vd-code textarea {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 1rem 1rem 1rem 0.25rem;
  border: 0;
  font: inherit;
  line-height: inherit;
  letter-spacing: 0;
  tab-size: 2;
  white-space: pre;
  overflow: auto;
  word-wrap: normal;
}

.vd-code .vd-hl {
  pointer-events: none;
  color: var(--vd-frame-ink);
  overflow: hidden;
}

.vd-code textarea {
  resize: none;
  background: transparent;
  color: transparent;
  caret-color: var(--vd-frame-ink);
  outline: none;
}

.vd-code textarea::selection {
  background: color-mix(in oklab, var(--primary) 30%, transparent);
  color: transparent;
}

.vd-editor:focus-within {
  box-shadow: inset 0 0 0 2px color-mix(in oklab, var(--ring) 55%, transparent);
}

.tk-c { color: #008000; font-style: italic; }
.tk-t { color: #800000; }
.tk-a { color: #e50000; }
.tk-s { color: #0000ff; }
.tk-p { color: #800000; }
.tk-k { color: #0000ff; }
.tk-n { color: #098658; }
.tk-b { color: #795e26; font-weight: 600; }

@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) .tk-c { color: #6a9955; }
  :root:not([data-theme='light']) .tk-t { color: #569cd6; }
  :root:not([data-theme='light']) .tk-a { color: #9cdcfe; }
  :root:not([data-theme='light']) .tk-s { color: #ce9178; }
  :root:not([data-theme='light']) .tk-p { color: #808080; }
  :root:not([data-theme='light']) .tk-k { color: #569cd6; }
  :root:not([data-theme='light']) .tk-n { color: #b5cea8; }
  :root:not([data-theme='light']) .tk-b { color: #ffd700; }
}

:root[data-theme='dark'] .tk-c { color: #6a9955; }
:root[data-theme='dark'] .tk-t { color: #569cd6; }
:root[data-theme='dark'] .tk-a { color: #9cdcfe; }
:root[data-theme='dark'] .tk-s { color: #ce9178; }
:root[data-theme='dark'] .tk-p { color: #808080; }
:root[data-theme='dark'] .tk-k { color: #569cd6; }
:root[data-theme='dark'] .tk-n { color: #b5cea8; }
:root[data-theme='dark'] .tk-b { color: #ffd700; }

.vd-url {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  align-self: center;
  min-width: 0;
  margin-left: 0.75rem;
  padding: 0.2rem 0.75rem;
  border-radius: var(--m-radius-full);
  background: color-mix(in oklab, var(--foreground) 6%, transparent);
  color: var(--muted-foreground);
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.vd-url .vd-icon {
  width: 0.8rem;
  height: 0.8rem;
}

.vd-error {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  align-self: center;
  min-width: 0;
  max-width: 60%;
  padding-right: 0.75rem;
  color: var(--danger);
  font-size: 0.75rem;
  font-weight: 600;
}

.vd-error[hidden] {
  display: none;
}

.vd-error span {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.ln-stage {
  height: 15rem;
  background: var(--background);
}

.ln-stage iframe {
  display: block;
  width: 100%;
  height: 100%;
  border: 0;
  background: transparent;
}

/* ----------------------------------------------------------------- end */

.ln-end {
  max-width: 48rem;
  margin: 1rem auto 0;
  padding: 2.5rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: var(--m-radius-3xl);
  background: var(--surface);
  box-shadow: var(--m-shadow-lg);
  text-align: center;
}

.ln-end-vudu {
  width: 8rem;
  height: auto;
  margin: 0 auto 1rem;
  animation: vd-float 5.5s ease-in-out infinite;
}

.ln-score {
  margin-top: 1rem;
  font-weight: 600;
  color: var(--primary);
}

.ln-recap {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr));
  gap: 0.5rem;
  margin-top: 1.25rem;
  text-align: left;
}

.ln-recap button {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.55rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: var(--m-radius-lg);
  background: var(--surface);
  font-size: 0.875rem;
  cursor: pointer;
  transition: transform 200ms, border-color 200ms;
}

.ln-recap button:hover {
  transform: translateY(-2px);
  border-color: color-mix(in oklab, var(--primary) 50%, var(--border));
}

.ln-recap .vd-icon {
  flex: none;
  width: 1rem;
  height: 1rem;
  color: var(--muted-foreground);
}

.ln-recap .is-done .vd-icon {
  color: var(--success);
}

.ln-end.ln-enter .ln-recap li {
  animation: ln-enter 420ms cubic-bezier(0.2, 0.8, 0.3, 1) both;
  animation-delay: calc(var(--i, 0) * 60ms + 150ms);
}

@media (prefers-reduced-motion: reduce) {
  .ln-bar i,
  .ln-dot,
  .ln-recap button {
    transition: none;
  }
  .ln-enter,
  .ln-pop,
  .ln-flash,
  .ln-end-vudu,
  .ln-live i,
  .ln-next-ready .vd-icon,
  .ln-task[data-state='waiting'] .ln-task-icon,
  .ln-end.ln-enter .ln-recap li {
    animation: none !important;
  }
}

/* Vudu hops when a task is solved, the same hop as on the home page. */
@keyframes vd-hop {
  0%,
  100% {
    transform: translateY(0) rotate(0);
  }
  30% {
    transform: translateY(-22px) rotate(-8deg);
  }
  60% {
    transform: translateY(0) rotate(5deg);
  }
}

.ln-vudu.vd-hop {
  animation: vd-hop 650ms cubic-bezier(0.3, 1.4, 0.6, 1);
}

@media (prefers-reduced-motion: reduce) {
  .ln-vudu.vd-hop {
    animation: none;
  }
}