/* ByteBellEducation
   Look and feel follows the logo: a green chalkboard in a wooden frame, white chalk lettering. */

@font-face {
  font-family: "Oswald";
  font-weight: 500;
  font-style: normal;
  font-display: swap;
  src: url("../fonts/oswald-latin-500-normal.woff2") format("woff2");
}
@font-face {
  font-family: "Oswald";
  font-weight: 700;
  font-style: normal;
  font-display: swap;
  src: url("../fonts/oswald-latin-700-normal.woff2") format("woff2");
}

:root {
  /* Paper (light) theme */
  --bg: #f7f4ea;
  --bg-soft: #efe9d6;
  --card: #fffdf6;
  --line: #e3dbc4;
  --text: #1c2b1f;
  --muted: #566659;
  --link: #17601a;
  --primary: #1f6b1c;
  --primary-ink: #ffffff;
  --ok: #1a7f37;
  --bad: #b3261e;
  --wood: #c98a44;
  --wood-dark: #8f5a22;
  --board: #1d5410;
  --board-light: #2a6d1c;
  --chalk: #f7f7f2;
  --chalk-yellow: #f2c14e;
  --code-bg: #14301a;
  --code-text: #eaf5e6;
  --inline-bg: #efe9d6;
  --shadow: 0 6px 18px rgba(28, 43, 31, .10);
  --radius: 14px;
  --heading: "Oswald", "Arial Narrow", Impact, system-ui, sans-serif;
}
:root[data-theme="dark"] {
  --bg: #0d1a10;
  --bg-soft: #14261a;
  --card: #14261a;
  --line: #28432f;
  --text: #e9f2e7;
  --muted: #9fb6a3;
  --link: #f2c14e;
  --primary: #f2c14e;
  --primary-ink: #241a00;
  --ok: #56d364;
  --bad: #ff7b72;
  --board: #123a0b;
  --board-light: #1b5013;
  --code-bg: #0a140c;
  --inline-bg: #1c3323;
  --shadow: 0 6px 18px rgba(0, 0, 0, .35);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0d1a10; --bg-soft: #14261a; --card: #14261a; --line: #28432f; --text: #e9f2e7; --muted: #9fb6a3;
    --link: #f2c14e; --primary: #f2c14e; --primary-ink: #241a00; --ok: #56d364; --bad: #ff7b72;
    --board: #123a0b; --board-light: #1b5013; --code-bg: #0a140c; --inline-bg: #1c3323;
    --shadow: 0 6px 18px rgba(0, 0, 0, .35);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
a { color: var(--link); }
main { flex: 1; width: 100%; max-width: 1200px; margin: 0 auto; padding: 28px 16px 56px; outline: none; }

/* ---------- Header: the chalkboard bar with a wooden edge ---------- */
.site-header {
  position: relative;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 10px 20px;
  color: var(--chalk);
  background:
    radial-gradient(120% 160% at 15% 0%, rgba(255,255,255,.10), transparent 55%),
    radial-gradient(90% 140% at 85% 100%, rgba(255,255,255,.07), transparent 60%),
    linear-gradient(180deg, var(--board-light), var(--board));
  border-bottom: 6px solid var(--wood);
  box-shadow: 0 3px 0 var(--wood-dark), 0 8px 18px rgba(0,0,0,.18);
}
.brand { display: flex; align-items: center; gap: 12px; color: var(--chalk); text-decoration: none; }
.brand img { border-radius: 9px; border: 2px solid var(--wood); background: var(--board); }
.brand-name {
  font-family: var(--heading); font-weight: 700; font-size: 22px; letter-spacing: .06em; text-transform: uppercase; line-height: 1;
}
.brand-name span { display: block; font-weight: 500; font-size: 12px; letter-spacing: .32em; opacity: .85; margin-top: 3px; }

.site-footer {
  display: flex; flex-wrap: wrap; gap: 8px 24px; justify-content: space-between;
  padding: 18px 20px; color: var(--chalk); font-size: 13px;
  background: linear-gradient(180deg, var(--board), var(--board-light));
  border-top: 6px solid var(--wood);
}
.site-footer a { color: var(--chalk-yellow); }

/* ---------- Buttons ---------- */
.btn {
  cursor: pointer; border: 1px solid var(--line); background: var(--card); color: var(--text);
  padding: 9px 18px; border-radius: 10px; font: inherit; font-size: 14px; text-decoration: none; display: inline-block;
}
.btn:hover { border-color: var(--primary); }
.btn:focus-visible, a:focus-visible, textarea:focus-visible, button:focus-visible { outline: 3px solid var(--chalk-yellow); outline-offset: 2px; }
.btn.primary { background: var(--primary); color: var(--primary-ink); border-color: var(--primary); font-weight: 600; }
.btn.primary:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; }
.site-header .btn { background: rgba(255,255,255,.10); color: var(--chalk); border-color: rgba(255,255,255,.35); }
.site-header .btn:hover { background: rgba(255,255,255,.2); border-color: var(--chalk); }
.btn[disabled] { opacity: .55; cursor: wait; }

/* ---------- Typography ---------- */
h1, h2, h3 { font-family: var(--heading); font-weight: 700; letter-spacing: .02em; }
h1 { font-size: clamp(30px, 5vw, 48px); line-height: 1.12; margin: 0 0 12px; text-transform: uppercase; }
h2 { font-size: 26px; margin: 36px 0 12px; text-transform: uppercase; }
h3 { font-size: 20px; margin: 22px 0 6px; }
.lead { color: var(--muted); font-size: 18px; max-width: 58ch; margin: 0 0 22px; }
.crumbs { color: var(--muted); font-size: 14px; margin-bottom: 14px; }

/* Section headings get a chalk-line underline */
main > h2 { display: flex; align-items: center; gap: 14px; }
main > h2::after { content: ""; flex: 1; height: 3px; border-radius: 3px; background: repeating-linear-gradient(90deg, var(--wood) 0 14px, transparent 14px 20px); opacity: .55; }

/* ---------- Home hero ---------- */
.hero { display: grid; grid-template-columns: 1fr; gap: 24px; align-items: center; margin-bottom: 8px; }
@media (min-width: 900px) { .hero { grid-template-columns: 1.05fr 1fr; gap: 40px; } }
.hero h1 { color: var(--primary); }
:root[data-theme="dark"] .hero h1 { color: var(--chalk-yellow); }
.hero-art { width: 100%; height: auto; border-radius: 12px; box-shadow: var(--shadow); display: block; }
.cta-row { display: flex; flex-wrap: wrap; gap: 10px; }
.hero .btn { padding: 12px 22px; font-size: 16px; }

/* ---------- Cards ---------- */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(270px, 1fr)); gap: 18px; margin-top: 8px; }
.card {
  display: block; position: relative; background: var(--card); border: 1px solid var(--line); border-top: 5px solid var(--wood);
  border-radius: var(--radius); padding: 20px; color: var(--text); text-decoration: none; box-shadow: var(--shadow);
  transition: transform .15s ease, border-color .15s ease;
}
a.card:hover { border-color: var(--primary); border-top-color: var(--wood); transform: translateY(-3px); }
.card h3 { margin: 0 0 6px; text-transform: uppercase; letter-spacing: .04em; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
.tag { display: inline-block; font-size: 12px; padding: 2px 10px; border-radius: 99px; background: var(--bg-soft); border: 1px solid var(--line); color: var(--muted); margin-top: 14px; }
.tag.soon { color: var(--wood-dark); border-color: var(--wood); }
:root[data-theme="dark"] .tag.soon { color: var(--chalk-yellow); }
.card.disabled { opacity: .62; cursor: default; box-shadow: none; }

.progress { height: 8px; background: var(--bg-soft); border: 1px solid var(--line); border-radius: 99px; overflow: hidden; margin-top: 14px; }
.progress > span { display: block; height: 100%; background: var(--primary); }

/* ---------- Course page ---------- */
.lesson-list { list-style: none; padding: 0; margin: 18px 0 0; display: grid; gap: 10px; }
.lesson-list a {
  display: flex; align-items: center; gap: 14px; padding: 14px 16px; border-radius: var(--radius);
  background: var(--card); border: 1px solid var(--line); border-left: 5px solid var(--wood); color: var(--text); text-decoration: none;
}
.lesson-list a:hover { border-color: var(--primary); border-left-color: var(--wood); }
.lesson-list .num {
  flex: none; width: 34px; height: 34px; border-radius: 50%; display: grid; place-items: center;
  background: var(--board); color: var(--chalk); font-family: var(--heading); font-size: 16px;
}
.lesson-list .done .num { background: var(--ok); color: #fff; }

/* ---------- Lesson page ---------- */
.lesson { display: grid; grid-template-columns: 1fr; gap: 24px; }
@media (min-width: 960px) { .lesson { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); align-items: start; } .workspace { position: sticky; top: 16px; } }
.lesson.no-exercise { grid-template-columns: 1fr; max-width: 78ch; }
.prose { min-width: 0; }
.prose p, .prose li { max-width: 68ch; }
.lesson.no-exercise .prose p, .lesson.no-exercise .prose li { max-width: none; }
.prose h1 { color: var(--primary); }
:root[data-theme="dark"] .prose h1 { color: var(--chalk-yellow); }
.prose a { text-decoration: underline; text-underline-offset: 2px; }
.prose code { background: var(--inline-bg); border: 1px solid var(--line); padding: 1px 6px; border-radius: 6px; font-size: .92em; }
.prose pre {
  background: var(--code-bg); color: var(--code-text); border: 3px solid var(--wood); border-radius: 10px;
  padding: 14px; overflow-x: auto; box-shadow: inset 0 0 24px rgba(0,0,0,.25);
}
.prose pre code { background: none; border: 0; padding: 0; color: inherit; }
.prose .tip { border-left: 5px solid var(--wood); background: var(--bg-soft); padding: 8px 16px; border-radius: 0 10px 10px 0; margin: 16px 0; }
.prose .tip p { margin: 6px 0; }
.prose .table-wrap { overflow-x: auto; margin: 16px 0; border: 1px solid var(--line); border-radius: 10px; background: var(--card); }
.prose table { border-collapse: collapse; width: 100%; font-size: 14.5px; }
.prose th, .prose td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); white-space: nowrap; }
.prose tbody tr:last-child td { border-bottom: 0; }
.prose thead { background: var(--board); color: var(--chalk); }
.prose th { font-family: var(--heading); font-weight: 500; font-size: 14px; text-transform: uppercase; letter-spacing: .06em; }

/* The editor is a small chalkboard in a wooden frame */
.workspace {
  background: var(--card); border: 1px solid var(--line); border-top: 5px solid var(--wood);
  border-radius: var(--radius); padding: 16px; box-shadow: var(--shadow);
}
.workspace label { display: block; font-family: var(--heading); font-size: 15px; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); margin-bottom: 6px; }
#editor {
  width: 100%; min-height: 230px; resize: vertical; tab-size: 4;
  background: var(--code-bg); color: var(--code-text); border: 3px solid var(--wood); border-radius: 10px;
  padding: 12px; font: 14px/1.55 ui-monospace, SFMono-Regular, Consolas, monospace; caret-color: var(--chalk-yellow);
}
.actions { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0; }
#output {
  min-height: 80px; max-height: 260px; overflow: auto; margin: 0; white-space: pre-wrap; word-break: break-word;
  background: var(--code-bg); color: var(--code-text); border: 1px solid var(--line); border-radius: 10px; padding: 12px;
  font: 14px/1.5 ui-monospace, SFMono-Regular, Consolas, monospace;
}
.result { margin: 12px 0 0; padding: 10px 14px; border-radius: 10px; font-size: 15px; border: 2px solid var(--line); background: var(--card); }
.result.ok { border-color: var(--ok); color: var(--ok); }
.result.bad { border-color: var(--bad); color: var(--bad); }
.result:empty { display: none; }

.lesson-nav { display: flex; justify-content: space-between; gap: 12px; margin-top: 34px; }
.loading, .noscript, .empty { color: var(--muted); }
.noscript { padding: 16px; }
.error-box { border: 2px solid var(--bad); color: var(--bad); border-radius: var(--radius); padding: 16px; background: var(--card); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .card { transition: none; }
  a.card:hover { transform: none; }
}
@media (max-width: 480px) {
  .brand-name { font-size: 18px; }
  .brand-name span { letter-spacing: .22em; }
}