@font-face {
  font-family: "STIX Two Text";
  src: url("fonts/stix-two-text-500.woff2") format("woff2");
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "STIX Two Text";
  src: url("fonts/stix-two-text-600.woff2") format("woff2");
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "STIX Two Text";
  src: url("fonts/stix-two-text-italic-500.woff2") format("woff2");
  font-weight: 500;
  font-style: italic;
  font-display: swap;
}
@font-face {
  font-family: "STIX figures";
  src: url("fonts/stix-two-text-figures-500.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
  unicode-range: U+0030-0039;
  size-adjust: 103.5%;
}
@font-face {
  font-family: "STIX figures";
  src: url("fonts/stix-two-text-figures-700.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
  unicode-range: U+0030-0039;
  size-adjust: 103.5%;
}
@font-face {
  font-family: "Atkinson Hyperlegible Next";
  src: url("fonts/atkinson-hyperlegible-next-400.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "Atkinson Hyperlegible Next";
  src: url("fonts/atkinson-hyperlegible-next-700.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "STIX fallback";
  src: local("Times New Roman");
  size-adjust: 104%;
  ascent-override: 76%;
  descent-override: 24%;
}
@font-face {
  font-family: "Atkinson fallback";
  src: local("Arial");
  size-adjust: 103%;
  ascent-override: 92%;
  descent-override: 24%;
}

:root {
  --paper: #F5F7F0;
  --pad: #E6EDDB;
  --white: #FFFFFF;
  --sheet: #FFFFFF;
  --graphite: #24292B;
  --graphite-soft: #4C5450;
  --rule: #BCC6B5;
  --red: #B0241C;
  --red-deep: #8C1C16;

  --serif: "STIX Two Text", "STIX fallback", "Times New Roman", serif;
  --sans: "STIX figures", "Atkinson Hyperlegible Next", "Atkinson fallback", Arial, sans-serif;

  --s0: 1.125rem;
  --s1: 1.5rem;
  --s2: 2rem;
  --s3: clamp(2rem, 1.6rem + 1.4vw, 2.666rem);
  --s4: clamp(2.5rem, 1.45rem + 4.5vw, 4.5rem);

  --sp-1: 0.5rem;
  --sp-2: 1rem;
  --sp-3: 1.5rem;
  --sp-4: 2rem;
  --sp-5: 3rem;
  --sp-6: 4.5rem;
  --sp-7: 6.75rem;

  --gutter: 1.5rem;
  --edge: clamp(1.25rem, 4vw, 3rem);
  --measure: 34em;
}

*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  margin: 0;
  overflow-x: clip;
  background: var(--paper);
  color: var(--graphite);
  font-family: var(--sans);
  font-size: var(--s0);
  line-height: 1.55;
  font-variant-numeric: proportional-nums;
}

h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 500;
  margin: 0;
  text-wrap: balance;
}
h1 { font-size: var(--s4); line-height: 1.04; letter-spacing: -0.015em; }
h2 { font-size: var(--s3); line-height: 1.12; letter-spacing: -0.01em; }
h3 { font-size: var(--s1); line-height: 1.2; font-weight: 600; }
h4 { font-size: var(--s0); line-height: 1.3; font-weight: 600; }

p { margin: 0; max-width: var(--measure); text-wrap: pretty; }
p + p { margin-top: var(--sp-2); }

a { color: inherit; text-decoration-thickness: 1px; text-underline-offset: 0.2em; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible { outline: 3px solid var(--red); outline-offset: 3px; }
::selection { background: var(--red); color: var(--white); }
input, textarea { caret-color: var(--red); }

i { font-family: var(--serif); font-style: italic; font-weight: 500; }

.tnum { font-variant-numeric: tabular-nums lining-nums; }
input, textarea, fieldset { scroll-margin-block: 6rem; }
.m { font-family: var(--serif); font-weight: 500; font-variant-numeric: lining-nums; }
.nowrap { white-space: nowrap; }

.wrap {
  width: 100%;
  max-width: calc(75rem + 2 * var(--edge));
  margin-inline: auto;
  padding-inline: var(--edge);
}

.skip {
  position: absolute;
  left: var(--sp-2);
  top: -4rem;
  z-index: 10;
  padding: var(--sp-1) var(--sp-2);
  background: var(--white);
  color: var(--graphite);
}
.skip:focus { top: var(--sp-1); }

/* Concept banner */
.concept {
  background: var(--graphite);
  color: var(--paper);
  font-size: 0.9375rem;
  line-height: 1.45;
}
.concept p { padding-block: 0.625rem; }

/* Masthead */
.masthead__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-2) var(--sp-3);
  padding-block: var(--sp-3);
}
.wordmark {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  margin: 0;
}
.wordmark__mark { fill: var(--red); flex: none; }
.wordmark__name {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.375rem;
  line-height: 1;
  letter-spacing: 0.005em;
}
.masthead__nav {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  font-size: 1rem;
}
.masthead__nav a:not(.button) { padding-block: 0.75rem; }
@media (max-width: 34rem) {
  .masthead__nav { display: none; }
}

/* Buttons */
.button {
  display: inline-flex;
  align-items: center;
  min-height: 3rem;
  padding: 0.75rem 1.5rem;
  border: 0;
  border-radius: 2px;
  background: var(--red);
  color: var(--white);
  font: 700 1.125rem/1.2 var(--sans);
  text-decoration: none;
  cursor: pointer;
}
.button:hover { background: var(--red-deep); }
.button:active { background: var(--red-deep); transform: translateY(1px); }
.button:focus-visible { outline-color: var(--graphite); }
.button--small { min-height: 2.75rem; padding: 0.625rem 1.125rem; font-size: 1rem; }

/* Sections */
.hero, .lesson, .syllabus, .groups, .tutors, .faq, .book { padding-block: var(--sp-6); }
.hero { padding-top: var(--sp-3); padding-bottom: var(--sp-4); }
@media (min-width: 60rem) {
  .lesson, .syllabus, .groups, .tutors, .faq, .book { padding-block: var(--sp-7); }
  .hero { padding-block: var(--sp-4) var(--sp-5); }
}

.section-head { display: grid; gap: var(--sp-2); margin-bottom: var(--sp-5); }

/* Hero */
.hero__grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--sp-5); }
.hero__text { align-self: center; }
.lede { font-size: 1.3125rem; line-height: 1.45; margin-top: var(--sp-3); max-width: 28em; }
.hero__action {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--sp-2) var(--sp-3);
  margin-top: var(--sp-4);
}
.quiet-link { padding-block: 0.75rem; }
.hero__note { margin-top: var(--sp-3); font-size: 1rem; color: var(--graphite-soft); max-width: 30em; }

/* Plot */
.plot { margin: 0; }
.plot__canvas {
  position: relative;
  container-type: inline-size;
  background: var(--pad);
}
.plot__svg { display: block; width: 100%; height: auto; }
.plot__canvas p { position: absolute; margin: 0; max-width: none; line-height: 1.2; }
.plot__eq {
  left: 22%;
  top: 5%;
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(0.9375rem, 3.4cqi, 1.3125rem);
  font-variant-numeric: lining-nums;
}
.plot__label {
  color: var(--red);
  font-size: clamp(0.75rem, 2.55cqi, 0.9375rem);
  font-weight: 700;
  font-variant-numeric: lining-nums;
}
.plot__label .m { font-weight: 600; }
.plot__label i { font-weight: 500; }
.plot__label--max { left: 33.333%; bottom: 63%; transform: translateX(-50%); text-align: center; }
.plot__label--inf { right: 51.5%; top: 59.5%; text-align: right; }
.plot__label--min { left: 66.667%; top: 82.5%; transform: translateX(-50%); text-align: center; }
.plot__label--int { right: 85.5%; top: 68.5%; text-align: right; }
.plot__axis { font-size: clamp(1rem, 3.6cqi, 1.375rem); }
.plot__axis--x { left: 95%; top: 81.5%; }
.plot__axis--y { left: 11%; top: 0.5%; }
.plot figcaption {
  margin-top: var(--sp-2);
  font-size: 0.9375rem;
  line-height: 1.45;
  color: var(--graphite-soft);
  max-width: 36em;
}
@media (max-width: 37.5rem) {
  .plot__canvas { margin-inline: calc(-1 * var(--edge)); }
}

@media (prefers-reduced-motion: no-preference) {
  .plot__curve {
    stroke-dasharray: 1;
    stroke-dashoffset: 1;
    animation: draw 1.1s cubic-bezier(0.65, 0, 0.35, 1) 0.2s forwards;
  }
  .plot__points, .plot__marks, .plot__label {
    animation: appear 0.3s cubic-bezier(0.16, 1, 0.3, 1) 1.25s both;
  }
}
@keyframes draw { to { stroke-dashoffset: 0; } }
@keyframes appear { from { opacity: 0; } to { opacity: 1; } }

/* Lesson timeline */
.timeline { list-style: none; margin: 0; padding: 0; border-bottom: 1px solid var(--rule); }
.timeline__row {
  display: grid;
  gap: var(--sp-1) var(--gutter);
  padding-block: var(--sp-3);
  border-top: 1px solid var(--rule);
}
.timeline__time { font-size: 1rem; color: var(--graphite-soft); }
.timeline__time .tnum { font-weight: 700; color: var(--graphite); }
.timeline__body p { margin-top: var(--sp-1); }
.timeline__track {
  position: relative;
  height: 0.875rem;
  margin-top: var(--sp-1);
  background: linear-gradient(var(--rule), var(--rule)) center / 100% 1px no-repeat;
}
.timeline__track::before, .timeline__track::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--rule);
}
.timeline__track::before { left: 0; }
.timeline__track::after { right: 0; }
.timeline__bar { position: absolute; top: 0; bottom: 0; background: var(--graphite); }
.timeline__bar--1 { left: 0; width: 11.111%; }
.timeline__bar--2 { left: 11.111%; width: 38.889%; }
.timeline__bar--3 { left: 50%; width: 38.889%; }
.timeline__bar--4 { left: 88.889%; width: 11.111%; }

/* Syllabus */
.syllabus { background: var(--sheet); }
.syllabus__grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--sp-5); }
.syllabus__text h2 { margin-bottom: var(--sp-3); }
.topics__title { font-size: var(--s0); font-weight: 600; margin-bottom: var(--sp-3); color: var(--graphite-soft); }
.topics { display: grid; gap: var(--sp-4); }
.topics h4 { padding-bottom: var(--sp-1); border-bottom: 1px solid var(--graphite); margin-bottom: var(--sp-1); }
.topics ul { list-style: none; margin: 0; padding: 0; }
.topics li { padding-block: 0.4rem; border-bottom: 1px solid var(--rule); line-height: 1.4; }

/* Groups */
.groups { background: var(--pad); }
.groups__grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--sp-4); }
.groups table { width: 100%; border-collapse: collapse; font-size: 1.125rem; }
.groups caption { text-align: left; caption-side: bottom; padding-top: var(--sp-2); font-size: 0.9375rem; color: var(--graphite-soft); }
.groups th, .groups td { text-align: left; padding: 0.75rem 1rem 0.75rem 0; vertical-align: top; }
.groups thead th { font-size: 0.9375rem; font-weight: 700; color: var(--graphite-soft); border-bottom: 1px solid var(--graphite); padding-top: 0; }
.groups tbody td { border-bottom: 1px solid var(--rule); font-variant-numeric: tabular-nums lining-nums; }
.groups__course th {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.3125rem;
  padding-top: var(--sp-3);
  border-bottom: 1px solid var(--rule);
}
.groups td:last-child { white-space: nowrap; padding-right: 0; }
@media (max-width: 40rem) {
  .groups table { font-size: 1rem; }
  .groups .day { display: block; }
}
@media (min-width: 26rem) {
  .groups .places { white-space: nowrap; }
}
@media (max-width: 19.99rem) {
  .groups td .nowrap { white-space: normal; }
}
.fee__amount {
  font-family: var(--serif);
  font-weight: 600;
  font-size: var(--s2);
  line-height: 1;
  font-variant-numeric: lining-nums;
  margin-right: 0.25rem;
}
.fee { font-size: 1.125rem; }
.groups__fees .button { margin-top: var(--sp-2); }

/* Tutors */
.tutors__grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--sp-4); }
.tutor h3 { margin-bottom: var(--sp-1); }
.tutors__note { color: var(--graphite-soft); font-size: 1rem; }

/* FAQ */
.faq { background: var(--sheet); }
.faq__grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--sp-4); }
.faq__list { border-bottom: 1px solid var(--rule); }
.faq details { border-top: 1px solid var(--rule); }
.faq summary {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--sp-3);
  min-height: 2.75rem;
  padding-block: var(--sp-2);
  font-family: var(--serif);
  font-weight: 500;
  font-size: 1.3125rem;
  line-height: 1.3;
  cursor: pointer;
  list-style: none;
  text-wrap: balance;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  flex: none;
  font-family: var(--sans);
  font-weight: 400;
  font-size: 1.5rem;
  line-height: 1;
  color: var(--graphite-soft);
}
.faq details[open] summary::after { content: "\2212"; }
.faq details p { padding-bottom: var(--sp-3); }

/* Booking form */
.book { background: var(--pad); }
.book__grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--sp-4); }
.book__intro p { margin-top: var(--sp-2); }
.form {
  border-left: 2px solid var(--red);
  padding-left: clamp(1rem, 3vw, 2.5rem);
  max-width: 36rem;
}
.form__concept { font-size: 0.9375rem; color: var(--graphite-soft); margin-bottom: var(--sp-3); }
.field { margin: 0 0 var(--sp-3); padding: 0; border: 0; min-width: 0; }
.field > label, .field legend {
  display: block;
  font-weight: 700;
  font-size: 1.125rem;
  margin-bottom: 0.375rem;
  padding: 0;
}
.optional { font-weight: 400; color: var(--graphite-soft); }
.help { font-size: 0.9375rem; color: var(--graphite-soft); margin-top: 0.375rem; }
input[type="text"], input[type="email"], textarea {
  display: block;
  width: 100%;
  min-height: 3rem;
  padding: 0.625rem 0.75rem;
  border: 1.5px solid var(--graphite-soft);
  border-radius: 2px;
  background: var(--white);
  color: var(--graphite);
  font: 400 1.125rem/1.4 var(--sans);
}
textarea { resize: vertical; min-height: 7rem; }
input:focus-visible, textarea:focus-visible { outline-offset: 1px; border-color: var(--graphite); }
.choice { display: flex; align-items: center; gap: 0.625rem; min-height: 2.75rem; }
.choice input { width: 1.5rem; height: 1.5rem; margin: 0; accent-color: var(--red); flex: none; }
.choice label { flex: 1; font-size: 1.125rem; padding-block: 0.625rem; cursor: pointer; }
.help--before { margin: 0 0 var(--sp-1); }
.error { margin-top: 0.375rem; color: var(--red); font-weight: 700; font-size: 0.9375rem; }
.error[hidden] { display: none; }
input[aria-invalid="true"]:not([type="radio"]) { border-color: var(--red); box-shadow: inset 0 0 0 1px var(--red); }
@media (forced-colors: active) {
  input[aria-invalid="true"]:not([type="radio"]):not(:focus-visible) { outline: 1px solid; outline-offset: -2.5px; }
}
.form__status { margin-top: var(--sp-2); font-weight: 700; }
.form__status:empty { display: none; }

/* Footer */
.footer {
  background: var(--graphite);
  color: var(--paper);
  padding-block: var(--sp-5);
  font-size: 1rem;
}
.footer__inner { display: grid; gap: var(--sp-2); }
.footer .wordmark__mark { fill: #E8695F; }

/* Wide layouts: a 12-column grid */
@media (min-width: 48rem) {
  .topics { grid-template-columns: 1fr 1fr; }
  .tutors__grid { grid-template-columns: 1fr 1fr; }
  .tutors__grid h2, .tutors__note { grid-column: 1 / -1; }
  .timeline__row { grid-template-columns: 7rem minmax(0, 1fr); }
  .timeline__body, .timeline__track { grid-column: 2; }
}

@media (min-width: 64rem) {
  .hero__grid,
  .syllabus__grid,
  .groups__grid,
  .tutors__grid,
  .faq__grid,
  .book__grid {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    column-gap: var(--gutter);
  }
  .hero__text { grid-column: 1 / 7; }
  .plot { grid-column: 7 / 13; }

  .section-head { grid-template-columns: repeat(12, minmax(0, 1fr)); column-gap: var(--gutter); align-items: end; }
  .section-head h2 { grid-column: 1 / 6; }
  .section-head p { grid-column: 7 / 12; }

  .timeline__row { grid-template-columns: repeat(12, minmax(0, 1fr)); align-items: start; }
  .timeline__time { grid-column: 1 / 3; padding-top: 0.2rem; }
  .timeline__body { grid-column: 3 / 9; }
  .timeline__track { grid-column: 9 / 13; margin-top: 0.75rem; }

  .syllabus__text { grid-column: 1 / 6; }
  .syllabus__topics { grid-column: 7 / 13; }

  .groups__grid h2 { grid-column: 1 / -1; }
  .groups__table { grid-column: 1 / 8; }
  .groups__fees { grid-column: 9 / 13; }

  .tutors__grid h2 { grid-column: 1 / 5; grid-row: 1 / 3; }
  .tutor:nth-of-type(1) { grid-column: 5 / 9; }
  .tutor:nth-of-type(2) { grid-column: 9 / 13; }
  .tutors__note { grid-column: 5 / 12; }

  .faq__grid h2 { grid-column: 1 / 5; }
  .faq__list { grid-column: 5 / 13; }

  .book__intro { grid-column: 1 / 5; }
  .form { grid-column: 5 / 11; }

  .footer__inner { grid-template-columns: repeat(12, minmax(0, 1fr)); column-gap: var(--gutter); align-items: baseline; }
  .footer__inner > :nth-child(1) { grid-column: 1 / 5; }
  .footer__inner > :nth-child(2) { grid-column: 5 / 9; }
  .footer__inner > :nth-child(3) { grid-column: 9 / 13; }
}