/* ————————————————————————————————————————
   KETO SCHULE — chalkboard schoolhouse
   ———————————————————————————————————————— */

:root {
  --board: #16352C;
  --board-2: #1D4237;
  --line: #2C5A4B;
  --chalk: #F2EFE4;
  --chalk-dim: #A9C0B4;
  --yellow: #F5C542;
  --red: #E2654E;
  --display: "Bricolage Grotesque", "Arial Black", sans-serif;
  --body: "Inter", system-ui, sans-serif;
  --gutter: clamp(16px, 5vw, 72px);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background:
    radial-gradient(120% 80% at 50% -10%, var(--board-2), transparent 60%),
    var(--board);
  color: var(--chalk);
  font-family: var(--body);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* faint chalk dust */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 999;
  opacity: 0.045;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='220' height='220'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

::selection { background: var(--yellow); color: var(--board); }

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

:focus-visible {
  outline: 2px solid var(--yellow);
  outline-offset: 3px;
  border-radius: 4px;
}

/* header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px var(--gutter);
  background: color-mix(in srgb, var(--board) 85%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.wordmark {
  font-family: var(--display);
  font-weight: 800;
  font-size: 20px;
  color: var(--chalk);
  text-decoration: none;
  white-space: nowrap;
}

.wordmark span { color: var(--yellow); }

.site-header nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2.5vw, 26px);
  font-size: 13.5px;
  font-weight: 500;
}

.site-header nav a {
  text-decoration: none;
  color: var(--chalk-dim);
  transition: color 0.2s;
}

.site-header nav a:hover { color: var(--chalk); }

.nav-cta {
  color: var(--board) !important;
  background: var(--yellow);
  font-weight: 700;
  padding: 8px 16px;
  border-radius: 999px;
  transition: transform 0.2s, filter 0.2s;
}

.nav-cta:hover { filter: brightness(1.08); transform: translateY(-1px); }

/* hero */

.hero {
  position: relative;
  padding: clamp(80px, 14vh, 150px) var(--gutter) clamp(80px, 13vh, 140px);
  border-bottom: 1px solid var(--line);
  overflow: hidden;
}

/* ruled chalk lines like an exercise book */
.chalk-lines {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(
    to bottom,
    transparent 0,
    transparent 46px,
    color-mix(in srgb, var(--chalk) 7%, transparent) 46px,
    color-mix(in srgb, var(--chalk) 7%, transparent) 47px
  );
  mask-image: linear-gradient(to bottom, transparent, black 30%, black 75%, transparent);
  -webkit-mask-image: linear-gradient(to bottom, transparent, black 30%, black 75%, transparent);
}

.kicker {
  position: relative;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--yellow);
  margin-bottom: 22px;
}

.hero h1 {
  position: relative;
  font-family: var(--display);
  font-weight: 800;
  font-size: clamp(50px, 10vw, 132px);
  line-height: 0.98;
  letter-spacing: -0.025em;
  max-width: 13ch;
}

.hero h1 em {
  font-style: normal;
  color: var(--yellow);
  position: relative;
}

/* chalk underline */
.hero h1 em::after {
  content: "";
  position: absolute;
  left: 0.02em;
  right: 0.06em;
  bottom: -0.04em;
  height: 0.06em;
  background: var(--yellow);
  border-radius: 999px;
  opacity: 0.85;
  transform: rotate(-0.6deg);
}

.lede {
  position: relative;
  max-width: 58ch;
  margin-top: 28px;
  font-size: clamp(16px, 1.6vw, 19px);
  color: var(--chalk-dim);
}

.hero-ctas {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 36px;
}

.btn-chalk {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--display);
  font-weight: 700;
  font-size: 15.5px;
  color: var(--board);
  background: var(--yellow);
  text-decoration: none;
  border-radius: 999px;
  padding: 14px 26px;
  box-shadow: 0 8px 28px rgba(245, 197, 66, 0.25);
  transition: transform 0.15s, filter 0.2s;
}

.btn-chalk:hover { filter: brightness(1.07); transform: translateY(-2px); }

.btn-chalk.big { font-size: 17px; padding: 16px 32px; }

.btn-ghost {
  display: inline-flex;
  align-items: center;
  font-weight: 600;
  font-size: 15px;
  color: var(--chalk);
  text-decoration: none;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 14px 24px;
  transition: border-color 0.2s, transform 0.15s;
}

.btn-ghost:hover { border-color: var(--yellow); transform: translateY(-2px); }

/* sections */

.section {
  padding: clamp(66px, 10vh, 120px) var(--gutter);
  border-bottom: 1px solid var(--line);
}

.section-head { max-width: 820px; margin-bottom: clamp(34px, 5vh, 54px); }

.section-head h2 {
  font-family: var(--display);
  font-weight: 800;
  font-size: clamp(32px, 5vw, 56px);
  letter-spacing: -0.02em;
  line-height: 1.05;
  margin-bottom: 12px;
}

.translate { color: var(--chalk-dim); font-weight: 500; font-size: 0.55em; letter-spacing: 0; }

.section-head p { color: var(--chalk-dim); max-width: 58ch; }

/* lessons */

.lessons {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 18px;
  counter-reset: lesson;
}

.lesson {
  background: color-mix(in srgb, var(--board-2) 85%, transparent);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 26px 24px;
  transition: transform 0.25s, border-color 0.25s;
}

.lesson:hover {
  transform: translateY(-4px);
  border-color: color-mix(in srgb, var(--yellow) 55%, var(--line));
}

.lesson-no {
  display: inline-block;
  font-family: var(--display);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--board);
  background: var(--yellow);
  border-radius: 999px;
  padding: 5px 12px;
  margin-bottom: 16px;
}

.lesson h3 {
  font-family: var(--display);
  font-weight: 700;
  font-size: 21px;
  letter-spacing: -0.01em;
  margin-bottom: 10px;
}

.lesson p { color: var(--chalk-dim); font-size: 15px; }

/* rules */

.rules {
  list-style: none;
  max-width: 760px;
  display: grid;
  gap: 0;
}

.rules li {
  padding: 18px 4px;
  border-bottom: 1px dashed var(--line);
  font-size: clamp(16px, 2vw, 19px);
  color: var(--chalk-dim);
}

.rules li:first-child { border-top: 1px dashed var(--line); }

.rules strong { color: var(--chalk); font-family: var(--display); font-weight: 700; }

/* enroll */

.enroll { border-bottom: none; }

.enroll-card {
  max-width: 720px;
  margin: 0 auto;
  text-align: center;
  background:
    radial-gradient(130% 150% at 50% 0%, color-mix(in srgb, var(--yellow) 14%, transparent), transparent 60%),
    var(--board-2);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: clamp(40px, 7vw, 62px) clamp(24px, 5vw, 54px);
}

.badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--yellow);
  border: 1px solid color-mix(in srgb, var(--yellow) 55%, transparent);
  border-radius: 999px;
  padding: 6px 14px;
  margin-bottom: 20px;
}

.enroll-card h2 {
  font-family: var(--display);
  font-weight: 800;
  font-size: clamp(30px, 5vw, 48px);
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}

.enroll-card p { color: var(--chalk-dim); max-width: 50ch; margin: 0 auto 28px; }

/* footer */

.site-footer {
  padding: 40px var(--gutter) 52px;
  border-top: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 22px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.footer-links span { color: var(--chalk-dim); }

.footer-links a { text-decoration: none; color: var(--yellow); transition: color 0.2s; }
.footer-links a:hover { color: var(--chalk); }

.site-footer > p { color: var(--chalk-dim); font-size: 13px; max-width: 72ch; }

/* reveal */

.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .lesson:hover, .btn-chalk:hover, .btn-ghost:hover, .nav-cta:hover { transform: none; }
}

@media (max-width: 760px) {
  .site-header { flex-direction: column; align-items: flex-start; gap: 10px; }
  .site-header nav { flex-wrap: wrap; row-gap: 8px; }
}