/* Williams Maths — williamsmaths.com
   Palette and type lifted from the Russian Math Circle flyer (Sept 2026). */

:root {
  --navy: #0a2342;
  --navy-2: #0e2d55;
  --paper: #fbfaf7;
  --panel: #e8eff9;
  --panel-2: #f3f6fb;
  --blue: #1656b8;
  --slate: #3c567e;
  --ink: #14213a;
  --muted: #5b6b85;
  --line: #d9e0ea;
  --line-navy: rgba(255, 255, 255, 0.14);
  --pale: #c2d5ef;

  --serif: "Instrument Serif", Georgia, "Times New Roman", serif;
  --sans: "IBM Plex Sans", -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  --max: 1120px;
  --gutter: clamp(20px, 4vw, 40px);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.6;
  font-feature-settings: "kern", "liga";
}
img { max-width: 100%; display: block; }
a { color: inherit; }
h1, h2, h3, h4 { margin: 0; font-weight: 400; }

.wrap { max-width: var(--max); margin: 0 auto; padding-left: var(--gutter); padding-right: var(--gutter); }

/* ---------- Type ---------- */
.kicker {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--blue);
  font-weight: 500;
}
.on-navy .kicker { color: var(--pale); }
.display {
  font-family: var(--serif);
  line-height: 1.02;
  letter-spacing: -0.01em;
}
.display em, .lede em { font-style: italic; color: var(--blue); }
.on-navy .display em { color: #8fb6ec; }
.lede { font-family: var(--serif); font-size: clamp(26px, 3vw, 36px); line-height: 1.2; }
.small { font-size: 15px; color: var(--muted); }
.note { font-family: var(--serif); font-style: italic; color: var(--slate); font-size: 18px; }
strong { font-weight: 600; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 13px 20px;
  border-radius: 4px;
  font-family: var(--sans); font-weight: 600; font-size: 15px;
  text-decoration: none;
  border: 1.5px solid transparent;
  transition: background .15s, color .15s, border-color .15s;
  white-space: nowrap;
}
.btn-primary { background: var(--blue); color: #fff; border-color: var(--blue); }
.btn-primary:hover { background: #124a9f; border-color: #124a9f; }
.btn-ghost { background: transparent; color: var(--navy); border-color: var(--navy); }
.btn-ghost:hover { background: var(--navy); color: #fff; }
.on-navy .btn-ghost { color: #fff; border-color: rgba(255,255,255,.55); }
.on-navy .btn-ghost:hover { background: #fff; color: var(--navy); border-color: #fff; }
.btn svg { width: 18px; height: 18px; flex: none; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 20;
  background: rgba(251, 250, 247, 0.92);
  backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 24px; height: 64px; }
.brand { display: flex; align-items: baseline; gap: 12px; text-decoration: none; }
.brand .word { font-family: var(--serif); font-size: 24px; color: var(--navy); }
.brand .where { font-family: var(--mono); font-size: 11px; letter-spacing: .14em; text-transform: uppercase; color: var(--slate); }
.nav { display: flex; align-items: center; gap: 26px; }
.nav a { font-size: 15px; text-decoration: none; color: var(--slate); }
.nav a:hover { color: var(--navy); }
.nav a.btn { padding: 9px 14px; font-size: 14px; color: #fff; }
.nav a.btn:hover { color: #fff; }
.nav .signin { font-family: var(--mono); font-size: 12px; letter-spacing: .08em; text-transform: uppercase; }
.menu-toggle { display: none; background: none; border: 1px solid var(--line); border-radius: 4px; padding: 8px 10px; font-family: var(--mono); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; color: var(--navy); cursor: pointer; }

/* ---------- Hero ---------- */
.hero { background: var(--navy); color: #fff; }
.hero .wrap {
  display: grid; grid-template-columns: 1.25fr 1fr; gap: clamp(28px, 5vw, 72px);
  padding-top: clamp(40px, 6vw, 72px); padding-bottom: 0;
  align-items: end;
}
.hero-copy { padding-bottom: clamp(40px, 6vw, 72px); }
.hero h1 { font-size: clamp(56px, 8vw, 104px); margin: 18px 0 10px; }
.hero .by { font-family: var(--sans); font-size: 20px; color: #dbe6f7; margin: 0 0 14px; }
.hero .by .mono { font-family: var(--mono); font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--pale); margin-right: 10px; }
.hero .by strong { color: #fff; font-weight: 600; }
.hero .cred { font-family: var(--mono); font-size: 11.5px; letter-spacing: .14em; text-transform: uppercase; color: var(--pale); margin: 0 0 10px; }
.hero .warm { font-family: var(--serif); font-style: italic; font-size: 22px; line-height: 1.3; color: #dbe6f7; margin: 0 0 30px; max-width: 30ch; }
.hero .english { font-family: var(--serif); font-size: clamp(24px, 2.6vw, 32px); color: #8fb6ec; margin: 4px 0 18px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }
.hero-photo { position: relative; align-self: center; }
.hero-photo img { width: 100%; height: auto; aspect-ratio: 4 / 5; object-fit: cover; object-position: 50% 30%; }
.hero-photo figcaption { position: absolute; left: 0; bottom: 0; background: var(--navy); color: var(--pale); font-family: var(--mono); font-size: 11px; letter-spacing: .14em; text-transform: uppercase; padding: 8px 12px; }

/* ---------- Statement band ---------- */
.statement { border-bottom: 1px solid var(--line); }
.statement .wrap { display: grid; grid-template-columns: 1.2fr 1fr; gap: clamp(28px, 5vw, 72px); padding-top: 48px; padding-bottom: 48px; align-items: center; }
.statement p { margin: 0; }

/* ---------- Sections ---------- */
section { padding: clamp(56px, 8vw, 96px) 0; }
section.tight { padding: clamp(40px, 6vw, 64px) 0; }
.sec-head { display: flex; align-items: baseline; justify-content: space-between; gap: 24px; border-top: 1.5px solid var(--navy); padding-top: 14px; margin-bottom: 36px; }
.sec-head .kicker { color: var(--navy); }
.sec-head .aside { font-family: var(--mono); font-size: 12px; color: var(--muted); letter-spacing: .06em; }
h2.display { font-size: clamp(34px, 4.6vw, 56px); margin-bottom: 20px; }
h3 { font-family: var(--sans); font-size: 19px; font-weight: 600; color: var(--navy); }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(28px, 5vw, 72px); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.prose p { margin: 0 0 18px; }
.prose p:last-child { margin-bottom: 0; }

/* Three questions */
.questions { counter-reset: q; list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.questions li { counter-increment: q; border-top: 1px solid var(--line); padding-top: 18px; font-family: var(--serif); font-size: 24px; line-height: 1.25; color: var(--navy); }
.questions li::before { content: counter(q, decimal-leading-zero); display: block; font-family: var(--mono); font-size: 12px; letter-spacing: .14em; color: var(--blue); margin-bottom: 10px; }

/* Two ways in */
.way { border-left: 3px solid var(--navy); padding: 4px 0 4px 18px; margin-bottom: 26px; }
.way h3 { margin-bottom: 4px; }
.way p { margin: 0; }
.way.between { border-left-color: var(--blue); margin-top: 6px; }

/* Problem panel */
.problem { background: var(--panel); padding: clamp(28px, 4vw, 44px); border-radius: 6px; }
.problem .head { display: flex; justify-content: space-between; gap: 16px; margin-bottom: 20px; }
.problem .source { font-family: var(--mono); font-size: 12px; color: var(--slate); }
.problem .text { font-family: var(--sans); font-size: 17px; line-height: 1.6; color: var(--ink); }
.problem .text strong { font-weight: 600; }
.problem details { margin-top: 22px; border-top: 1px solid rgba(10,35,66,.15); padding-top: 14px; }
.problem summary { cursor: pointer; font-family: var(--mono); font-size: 12px; letter-spacing: .14em; text-transform: uppercase; color: var(--blue); font-weight: 500; list-style: none; }
.problem summary::-webkit-details-marker { display: none; }
.problem summary::after { content: " →"; }
.problem details[open] summary::after { content: " ↓"; }
.problem details p { margin: 12px 0 0; font-size: 15px; }
.problem .note { display: block; margin-top: 18px; font-size: 16px; }

/* Ladder */
.age-head { margin: 0 0 4px; color: var(--muted); }
.ladder { list-style: none; margin: 0 0 22px; padding: 0; }
.ladder li { display: grid; grid-template-columns: 56px 1fr; gap: 14px; align-items: baseline; padding: 14px 0; border-top: 1px solid var(--line); }
.ladder li:last-child { border-bottom: 1px solid var(--line); }
.ladder .age { font-family: var(--serif); font-size: 34px; color: var(--blue); line-height: 1; }
.ladder .comp { font-weight: 600; color: var(--navy); }
.ladder .tag { font-family: var(--mono); font-size: 12px; color: var(--muted); margin-left: 8px; }

/* Facts */
.facts { display: grid; grid-template-columns: repeat(5, 1fr); gap: 24px; margin-top: 8px; }
.facts .kicker { display: block; margin-bottom: 8px; color: var(--slate); }
.facts .v { font-size: 17px; color: var(--navy); }
.facts .v b { font-weight: 600; }
.on-navy .facts .kicker { color: var(--pale); }
.on-navy .facts .v { color: #fff; }

/* Private coaching */
.coaching { background: var(--panel-2); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.steps { list-style: none; margin: 0; padding: 0; counter-reset: s; }
.steps li { counter-increment: s; display: grid; grid-template-columns: 44px 1fr; gap: 14px; padding: 16px 0; border-top: 1px solid var(--line); }
.steps li::before { content: counter(s); font-family: var(--serif); font-size: 30px; color: var(--blue); line-height: 1; }
.steps li:last-child { border-bottom: 1px solid var(--line); }
.steps h3 { font-size: 17px; margin-bottom: 2px; }
.steps p { margin: 0; font-size: 15.5px; }

/* Joseph */
.joseph .wrap { display: grid; grid-template-columns: 1fr 1.4fr; gap: clamp(28px, 5vw, 72px); align-items: stretch; }
.joseph .photo { position: relative; min-height: 320px; }
.joseph img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; object-position: 50% 20%; border-radius: 4px; }
blockquote { margin: 28px 0 0; padding: 0 0 0 20px; border-left: 3px solid var(--blue); }
blockquote p { font-family: var(--serif); font-size: 26px; line-height: 1.25; color: var(--navy); margin: 0 0 8px; }
blockquote cite { font-family: var(--mono); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); font-style: normal; }

/* Workshop CTA */
.workshop { background: var(--navy); color: #fff; }
.workshop .wrap { display: grid; grid-template-columns: 1.4fr 1fr; gap: clamp(28px, 5vw, 72px); align-items: center; }
.workshop h2 { font-size: clamp(40px, 5.5vw, 64px); margin: 10px 0 16px; }
.workshop p { color: #dbe6f7; margin: 0 0 24px; }
.workshop .phone { font-family: var(--mono); font-size: 26px; font-weight: 600; letter-spacing: .04em; color: #fff; text-decoration: none; }
.workshop .phone-label { font-family: var(--mono); font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--pale); margin-left: 14px; }
.workshop .facts { grid-template-columns: repeat(2, 1fr); gap: 20px 28px; }
.workshop .card { border: 1px solid var(--line-navy); border-radius: 6px; padding: 28px; }
.workshop .card .kicker { margin-bottom: 14px; display: block; }
.workshop .card ul { margin: 0; padding: 0; list-style: none; }
.workshop .card li { padding: 10px 0; border-top: 1px solid var(--line-navy); font-size: 15.5px; color: #dbe6f7; }
.workshop .card li b { color: #fff; font-weight: 600; }

/* Footer */
.site-footer { border-top: 1px solid var(--line); padding: 28px 0 40px; }
.site-footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 14px 28px; font-family: var(--mono); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; color: var(--slate); }
.site-footer a { text-decoration: none; }
.site-footer a:hover { color: var(--navy); }
.site-footer .links { display: flex; flex-wrap: wrap; gap: 22px; }

/* Legal pages */
.legal { max-width: 760px; }
.legal h1 { font-family: var(--serif); font-size: 44px; margin: 8px 0 24px; }
.legal h2 { font-family: var(--sans); font-size: 18px; font-weight: 600; margin: 28px 0 8px; color: var(--navy); }

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  .grid-3, .questions { grid-template-columns: 1fr; gap: 18px; }
  .facts { grid-template-columns: repeat(3, 1fr); }
  .joseph .wrap { grid-template-columns: 1fr 1.2fr; }
}
@media (max-width: 760px) {
  body { font-size: 16px; }
  .nav { display: none; position: absolute; top: 64px; left: 0; right: 0; background: var(--paper); border-bottom: 1px solid var(--line); flex-direction: column; align-items: stretch; gap: 0; padding: 8px 0; }
  .nav.open { display: flex; }
  .nav a { padding: 12px var(--gutter); }
  .nav .btn { margin: 8px var(--gutter); width: calc(100% - 2 * var(--gutter)); justify-content: center; }
  .menu-toggle { display: inline-block; }
  .brand .where { display: none; }
  .hero .wrap, .statement .wrap, .grid-2, .joseph .wrap, .workshop .wrap { grid-template-columns: 1fr; }
  .joseph .photo { min-height: 0; }
  .joseph img { position: static; aspect-ratio: 4 / 5; height: auto; object-position: 50% 10%; }
  .hero .wrap { padding-top: 0; }
  .hero-copy { padding-top: 32px; }
  .hero-photo { order: -1; margin: 0 calc(-1 * var(--gutter)); }
  .workshop .phone-label { display: block; margin: 6px 0 0; }
  .hero-photo img { aspect-ratio: 1 / 1; object-position: 50% 25%; }
  .hero h1 { font-size: clamp(48px, 15vw, 72px); }
  .facts, .workshop .facts { grid-template-columns: repeat(2, 1fr); }
  .btn { width: 100%; justify-content: center; }
  .hero-actions { flex-direction: column; }
}