:root {
  color-scheme: light;
  --page-progress: 0%;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: #f5f1e8;
  font-family: 'DM Sans', sans-serif;
}

body::before {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 100;
  width: var(--page-progress);
  height: 3px;
  background: #e86f45;
  content: '';
  transition: width .12s ease-out;
}

.texture {
  background-image: radial-gradient(rgba(23, 62, 54, .055) .7px, transparent .7px);
  background-size: 7px 7px;
}

.font-mono-draw {
  font-family: 'DM Mono', monospace;
}

.focus-ring:focus-visible {
  outline: 3px solid #e86f45;
  outline-offset: 4px;
}

.dark-mode {
  color-scheme: dark;
  filter: invert(.9) hue-rotate(180deg);
}

.dark-mode img,
.dark-mode video {
  filter: invert(1) hue-rotate(180deg);
}

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

.page-intro {
  max-width: 48rem;
  padding: 5rem 0 3rem;
}

.lesson-reader-progress {
  position: fixed;
  top: 4.5rem;
  right: 0;
  left: 0;
  z-index: 45;
  border-bottom: 1px solid rgba(217, 213, 201, .8);
  background: rgba(245, 241, 232, .92);
  padding: .4rem max(1.25rem, calc((100vw - 1120px) / 2));
  backdrop-filter: blur(10px);
}

.lesson-reader-progress__meta {
  display: flex;
  justify-content: space-between;
  gap: .75rem;
  margin-bottom: .3rem;
  color: #68716c;
  font-family: 'DM Mono', monospace;
  font-size: .62rem;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.lesson-reader-progress__track {
  height: .24rem;
  overflow: hidden;
  border-radius: 999px;
  background: #e8e2d7;
}

.lesson-reader-progress__track > div {
  width: 0%;
  height: 100%;
  border-radius: inherit;
  background: #e86f45;
  transition: width .12s ease-out;
}

.lesson-reader-content {
  margin-top: 1rem;
}

.lesson-reader-content .is-complete {
  background: #2f896c;
}

@media (max-width: 640px) {
  .lesson-reader-progress { padding-right: 1.25rem; padding-left: 1.25rem; }
}

@media (prefers-reduced-motion: reduce) {
  .lesson-reader-progress__track > div { transition: none; }
}

[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity .65s ease, transform .65s ease;
}

[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

.quiz-option {
  display: block;
  border: 1px solid #d9d5c9;
  border-radius: 12px;
  padding: .7rem .85rem;
  transition: background-color .2s ease, border-color .2s ease, transform .2s ease;
}

.quiz-option:hover {
  border-color: #e86f45;
  background: rgba(232, 111, 69, .08);
  transform: translateX(3px);
}

.quiz-option.is-correct {
  border-color: #2f896c;
  background: rgba(47, 137, 108, .12);
}

.quiz-option.is-incorrect {
  border-color: #c84f46;
  background: rgba(200, 79, 70, .1);
}

.quiz-feedback {
  margin-top: .75rem;
  color: #68716c;
  font-size: .75rem;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  [data-reveal] { opacity: 1; transform: none; transition: none; }
}