/* Education Unlocked hub. Header, hero grid, buttons and footer follow the MathsUnlocked landing page. */
:root {
  --ink: #1F2937; --paper: #F7F9FB; --grid: #DCE8F1; --card: #FFFFFF; --locked: #EEF1F4; --amber-wash: #FBF3E6;
  --green: #2F6B4F; --blue: #1E7A68; --amber: #C97F1E; --muted: #8A97A6; --on-accent: #FFFFFF;
  --shadow: rgba(31,41,55,.10); --shadow-soft: rgba(31,41,55,.06); --page-bg: #F7F9FB;
  --muted-text: color-mix(in srgb, var(--ink) 66%, var(--card));
  --amber-strong: color-mix(in srgb, var(--amber) 70%, var(--ink));
  --border-strong: color-mix(in srgb, var(--ink) 55%, var(--card));
  --navy: color-mix(in srgb, var(--blue) 60%, #06241D);
  --sky: color-mix(in srgb, #6DB5A1 24%, var(--page-bg));
  --sky-mid: color-mix(in srgb, #6DB5A1 9%, var(--page-bg));
  --blue-wash: color-mix(in srgb, var(--blue) 9%, var(--card));
  --foot-bg: #0B2545; --foot-ink: #E8F1FA; --foot-muted: #A4BAD3; --foot-line: #1E3F6B; --foot-accent: #7FD6A8;
  --f-display: 'Fraunces', Georgia, serif; --f-body: 'Inter', system-ui, sans-serif;
  --ease: cubic-bezier(.2,.7,.2,1);
  color-scheme: light;
}
:root[data-theme="dark"] {
  --ink: #E6EBF1; --paper: #141A22; --grid: #2A3644; --card: #1C242F; --locked: #181E27; --amber-wash: #2E2617;
  --green: #5EBE94; --blue: #7CD3BC; --amber: #E0A94E; --muted: #8B98A7; --on-accent: #0E1319;
  --shadow: rgba(0,0,0,.5); --shadow-soft: rgba(0,0,0,.35); --page-bg: #0E1319;
  --navy: color-mix(in srgb, var(--blue) 70%, #fff);
  --foot-bg: #070D14; --foot-line: #1B2A3B;
  color-scheme: dark;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ink: #E6EBF1; --paper: #141A22; --grid: #2A3644; --card: #1C242F; --locked: #181E27; --amber-wash: #2E2617;
    --green: #5EBE94; --blue: #7CD3BC; --amber: #E0A94E; --muted: #8B98A7; --on-accent: #0E1319;
    --shadow: rgba(0,0,0,.5); --shadow-soft: rgba(0,0,0,.35); --page-bg: #0E1319;
    --navy: color-mix(in srgb, var(--blue) 70%, #fff);
    --foot-bg: #070D14; --foot-line: #1B2A3B;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; color: var(--ink); font: 400 16px/1.55 var(--f-body); -webkit-font-smoothing: antialiased; overflow-x: hidden;
  background: linear-gradient(180deg, var(--sky) 0, var(--sky-mid) 620px, var(--page-bg) 1700px) top left / 100% 1700px no-repeat, var(--page-bg);
}
h1, h2, h3, h4, p { margin: 0; }
a { color: inherit; }
button { font: inherit; color: inherit; }
:focus-visible { outline: 3px solid var(--blue); outline-offset: 2px; border-radius: 8px; }
svg.ic { flex-shrink: 0; display: block; }
.wrap { max-width: 1160px; margin: 0 auto; padding-inline: max(16px, env(safe-area-inset-left)) max(16px, env(safe-area-inset-right)); }
@media (min-width: 768px) { .wrap { padding-inline: max(24px, env(safe-area-inset-left)) max(24px, env(safe-area-inset-right)); } }
section { scroll-margin-top: 76px; }

/* header: round logo, name, BETA, links, one button */
.top { position: fixed; left: 0; right: 0; top: 0; padding-top: env(safe-area-inset-top); z-index: 40; background: var(--card); border-bottom: 1px solid var(--grid); box-shadow: 0 1px 0 var(--shadow-soft); }
.top .wrap { display: flex; align-items: center; gap: 12px; min-height: 64px; max-width: none; }
.topspace { height: calc(64px + env(safe-area-inset-top)); }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font: 700 18px var(--f-body); letter-spacing: -.01em; }
.roundel { width: 36px; height: 36px; border-radius: 50%; border: 1px solid var(--grid); display: block; }
.beta { font: 700 12px var(--f-body); letter-spacing: .06em; background: var(--amber-wash); color: var(--amber-strong); border: 1px solid var(--amber); border-radius: 6px; padding: 1px 6px; }
.nav { display: none; gap: 4px; margin-left: 14px; margin-right: auto; }
.nav a { padding: 0 12px; min-height: 44px; display: inline-flex; align-items: center; font-weight: 600; font-size: 15px; color: var(--muted-text); text-decoration: none; border-radius: 10px; white-space: nowrap; }
.nav a:hover { background: var(--grid); color: var(--ink); }
.top .spacer { flex: 1; }
@media (min-width: 880px) { .nav { display: flex; } .top .spacer { display: none; } }

/* buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 48px; padding: 0 22px; border-radius: 12px; border: 1px solid transparent; font: 700 16px var(--f-body); text-decoration: none; cursor: pointer; transition: transform .12s var(--ease), box-shadow .2s var(--ease), background .2s; white-space: nowrap; }
.btn:active { transform: scale(.98); }
.btn.p { background: var(--green); color: var(--on-accent); box-shadow: 0 6px 16px color-mix(in srgb, var(--green) 30%, transparent); }
.btn.s { background: var(--card); color: var(--ink); border-color: var(--border-strong); }
@media (hover: hover) { .btn.p:hover { transform: translateY(-1px); box-shadow: 0 10px 22px color-mix(in srgb, var(--green) 38%, transparent); } .btn.s:hover { background: var(--paper); } }
.btn.sm { min-height: 44px; padding: 0 16px; font-size: 15px; }
.btn svg { width: 18px; height: 18px; }

/* hero: graph-paper grid like the Maths page, centred */
.hero { position: relative; padding-block: 36px 8px; overflow: hidden; text-align: center; }
.hero-bg { position: absolute; inset: 0; z-index: -1; pointer-events: none;
  background-image: linear-gradient(color-mix(in srgb, var(--blue) 14%, transparent) 1px, transparent 1px), linear-gradient(90deg, color-mix(in srgb, var(--blue) 14%, transparent) 1px, transparent 1px);
  background-size: 32px 32px; -webkit-mask-image: linear-gradient(#000 40%, transparent); mask-image: linear-gradient(#000 40%, transparent); }
.eyebrow { font: 700 12px var(--f-body); letter-spacing: .09em; text-transform: uppercase; color: var(--blue); }
h1 { font: 700 clamp(40px, 7.4vw, 72px)/1.04 var(--f-display); letter-spacing: -.02em; margin: 14px 0 16px; text-wrap: balance; }
h1 em { display: block; font-style: normal; color: var(--navy); }
.lede { font-size: clamp(17px, 2vw, 20px); color: var(--muted-text); max-width: 56ch; margin-inline: auto; text-wrap: pretty; }
.micro { display: flex; flex-wrap: wrap; gap: 6px 20px; justify-content: center; margin: 18px 0 0; color: var(--muted-text); font-size: 15px; }
.micro span { display: inline-flex; align-items: center; gap: 7px; }
.micro svg { width: 16px; height: 16px; color: var(--green); }

/* sections */
.sec { padding-block: 28px 8px; }
.sec-head { display: grid; gap: 10px; margin-bottom: 26px; text-align: center; justify-items: center; }
h2 { font: 700 clamp(28px, 4.2vw, 42px)/1.1 var(--f-display); letter-spacing: -.01em; text-wrap: balance; }
.sub { font-size: 17px; color: var(--muted-text); max-width: 60ch; text-wrap: pretty; }

/* subject buttons: each in its own soft colour (--c) */
.subjects { display: grid; gap: 14px; grid-template-columns: repeat(auto-fill, minmax(min(100%, 250px), 1fr)); }
.sc { --c: #3B6FA0; position: relative; display: flex; flex-direction: column; gap: 8px; padding: 18px; border-radius: 16px; text-decoration: none; color: var(--ink);
  background: color-mix(in srgb, var(--c) 11%, var(--card)); border: 1px solid color-mix(in srgb, var(--c) 30%, var(--grid)); }
.sc .row { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.sc .ico { width: 46px; height: 46px; border-radius: 13px; display: grid; place-items: center; font: 700 19px var(--f-display);
  background: color-mix(in srgb, var(--c) 26%, var(--card)); color: color-mix(in srgb, var(--c) 72%, var(--ink)); }
.sc h3 { font: 700 21px/1.2 var(--f-display); }
.sc p { color: var(--muted-text); font-size: 14.5px; }
.codes { font: 600 12.5px var(--f-body); letter-spacing: .02em; color: var(--muted-text); }
.pill { font: 700 11.5px var(--f-body); letter-spacing: .04em; padding: 3px 10px; border-radius: 999px; white-space: nowrap;
  background: color-mix(in srgb, var(--c) 14%, var(--card)); color: color-mix(in srgb, var(--c) 70%, var(--ink)); border: 1px solid color-mix(in srgb, var(--c) 30%, var(--card)); }
.sc.live { box-shadow: 0 10px 26px color-mix(in srgb, var(--c) 20%, transparent); border-color: color-mix(in srgb, var(--c) 55%, var(--grid)); }
.sc.live .pill { background: var(--c); color: #fff; border-color: transparent; }
.sc .go { margin-top: auto; padding-top: 6px; display: inline-flex; align-items: center; gap: 6px; font-weight: 700; color: color-mix(in srgb, var(--c) 75%, var(--ink)); }
.sc .go svg { width: 18px; height: 18px; }
.sc.soon { cursor: default; }
@media (hover: hover) { a.sc.live { transition: transform .15s var(--ease), box-shadow .2s; } a.sc.live:hover { transform: translateY(-3px); box-shadow: 0 16px 34px color-mix(in srgb, var(--c) 28%, transparent); } }
.note { text-align: center; margin-top: 18px; color: var(--muted-text); font-size: 15px; }

/* how it works */
.how { display: grid; gap: 16px; grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr)); }
.how > div { padding: 22px; background: var(--card); border: 1px solid var(--grid); border-radius: 16px; box-shadow: 0 2px 0 var(--shadow-soft); }
.how h3 { font: 700 19px/1.25 var(--f-display); margin-bottom: 6px; }
.how p { color: var(--muted-text); font-size: 15.5px; }
.how .n { display: inline-grid; place-items: center; width: 34px; height: 34px; border-radius: 10px; background: var(--blue-wash); color: var(--blue); margin-bottom: 12px; }
.how .n svg { width: 18px; height: 18px; }

/* footer: same structure as the Maths page */
.foot { margin-top: 72px; background: var(--foot-bg); color: var(--foot-ink); }
.foot .wrap { padding-block: 56px 28px; display: grid; gap: 40px; }
.foot-top { display: flex; gap: 24px 40px; flex-wrap: wrap; justify-content: space-between; align-items: flex-start; }
.foot-brand { display: grid; gap: 14px; max-width: 340px; }
.foot-brand .roundel { width: 64px; height: 64px; border: 2px solid var(--foot-accent); }
.foot-brand p { color: var(--foot-muted); font-size: 16px; }
.foot-cols { display: grid; gap: 28px 24px; grid-template-columns: repeat(auto-fit, minmax(min(100%, 170px), 1fr)); }
.foot h4 { font: 700 15px var(--f-body); margin-bottom: 6px; }
.foot-cols a, .foot-cols span { display: flex; align-items: center; min-height: 40px; color: var(--foot-muted); font-size: 15px; text-decoration: none; }
.foot-cols a:hover { color: var(--foot-accent); }
.foot-cols .off { opacity: .6; }
.foot-bot { border-top: 1px solid var(--foot-line); padding-top: 22px; display: flex; gap: 16px; flex-wrap: wrap; justify-content: space-between; align-items: center; color: var(--foot-muted); font-size: 14px; }
.foot-right { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.seg { display: inline-flex; border: 1px solid var(--foot-line); border-radius: 12px; overflow: hidden; }
.seg button { border: 0; background: none; padding: 0 14px; min-height: 44px; font-weight: 600; font-size: 14px; cursor: pointer; color: var(--foot-muted); }
.seg button[aria-pressed="true"] { background: var(--foot-accent); color: #0B2545; }
.socials { display: flex; gap: 10px; }
.socials a { width: 44px; height: 44px; border-radius: 50%; border: 1px solid var(--foot-line); color: var(--foot-accent); display: grid; place-items: center; text-decoration: none; transition: background .2s, color .2s; }
.socials a:hover { background: var(--foot-accent); color: #0B2545; }
.lang { position: relative; }
.lang-btn { display: inline-flex; align-items: center; gap: 8px; min-height: 44px; padding: 0 14px; border-radius: 12px; border: 1px solid var(--foot-line); background: color-mix(in srgb, var(--foot-line) 45%, transparent); color: var(--foot-ink); font: 700 15px var(--f-body); cursor: pointer; }
.lang-btn:hover { border-color: var(--foot-accent); }
.lang-menu { position: absolute; right: 0; bottom: calc(100% + 8px); min-width: 200px; background: var(--foot-bg); border: 1px solid var(--foot-line); border-radius: 14px; padding: 6px; box-shadow: 0 16px 40px rgba(0,0,0,.45); z-index: 20; display: grid; gap: 2px; }
.lang-menu[hidden] { display: none; }
.lang-menu button { display: flex; justify-content: space-between; align-items: center; gap: 12px; min-height: 44px; padding: 0 12px; border: 0; border-radius: 10px; background: none; color: var(--foot-ink); font: 500 15px var(--f-body); cursor: pointer; text-align: left; }
.lang-menu button:hover, .lang-menu button:focus-visible { background: var(--foot-line); }
.lang-menu button svg { opacity: 0; }
.lang-menu button[aria-selected="true"] { color: var(--foot-accent); font-weight: 700; }
.lang-menu button[aria-selected="true"] svg { opacity: 1; }
.top-btn { display: inline-flex; align-items: center; gap: 8px; min-height: 44px; padding: 0 14px; border-radius: 999px; border: 1px solid var(--foot-line); background: none; color: var(--foot-ink); font-weight: 600; cursor: pointer; }
.top-btn:hover { border-color: var(--foot-accent); color: var(--foot-accent); }

@media (prefers-reduced-motion: reduce) { * { transition: none !important; scroll-behavior: auto !important; } }
.brand .name { white-space: nowrap; }
@media (max-width: 520px) {
  .top .wrap { gap: 8px; }
  .brand { gap: 8px; }
  .brand .name { font-size: 15px; }
  .beta { font-size: 11px; padding: 0 5px; }
  .top .btn.sm { padding: 0 12px; font-size: 14px; }
  /* subjects: Maths full width, the rest two to a row */
  .subjects { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
  .sc.live { grid-column: 1 / -1; }
  .sc { padding: 14px; }
  .sc .row { flex-wrap: wrap; gap: 8px; }
  .sc h3 { font-size: 19px; }
}