/* WDC challenge landing page
   One stylesheet, no build step. Tokens first, then base, layout, components. */

/* Fonts: self-hosted so no visitor data goes to a third-party font CDN (GDPR). */
@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
  src: url("fonts/inter-latin-wght-normal.woff2") format("woff2-variations");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

@font-face {
  font-family: "JetBrains Mono";
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url("fonts/jetbrains-mono-latin-400-normal.woff2") format("woff2");
}

@font-face {
  font-family: "JetBrains Mono";
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url("fonts/jetbrains-mono-latin-500-normal.woff2") format("woff2");
}

:root {
  --color-bg: #f3f8ff;
  --color-surface: #ffffff;
  --color-ink: #111316;
  --color-muted: #4b5360;
  --color-numeral: #5f6773;
  --color-border: #dce6f5;
  --color-border-soft: #e3e8ef;
  --color-rule: #c9d6e8;
  --color-input-border: #b9c4d2;
  --color-placeholder: #6b7380;
  --color-photo: #e9f1fc;
  --color-highlight: #fde5da;
  --color-accent: #ec4409;
  --color-accent-hover: #d23c07;

  --font-sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --page-max: 1240px;
  --page-gutter: clamp(16px, 4vw, 40px);
  --section-space: clamp(56px, 8vw, 112px);
  --column-gap: clamp(24px, 4vw, 56px);
  --radius-control: 4px;
}

/* Base */

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1,
h2,
h3,
p,
ol,
figure {
  margin: 0;
}

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

a:hover {
  color: var(--color-muted);
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* Layout */

.page {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 0 var(--page-gutter) 56px;
}

.site-header {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding: 28px 0;
}

.site-header__logo {
  display: block;
  height: 56px;
  width: auto;
}

.site-header__meta {
  font-size: 14px;
  color: var(--color-muted);
}

.section {
  border-top: 1px solid var(--color-border);
  padding: var(--section-space) 0;
}

.section--flush-top {
  border-top: 0;
  padding-top: clamp(56px, 7vw, 96px);
}

.stack {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.stack--loose {
  gap: 32px;
}

/* Typography */

.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.eyebrow::before {
  content: "";
  width: 8px;
  height: 8px;
  flex: 0 0 auto;
  background: var(--color-accent);
}

.section-title {
  font-size: clamp(30px, 3vw, 44px);
  line-height: 1.08;
  letter-spacing: -0.025em;
  font-weight: 500;
}

.lede {
  font-size: 19px;
  line-height: 1.45;
  max-width: 40ch;
}

.muted {
  color: var(--color-muted);
}

.numbered {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
  font-size: 18px;
  line-height: 1.4;
  counter-reset: item;
}

.numbered li {
  display: flex;
  gap: 16px;
  counter-increment: item;
}

.numbered li::before {
  content: counter(item);
  min-width: 14px;
  color: var(--color-numeral);
}

.numbered--compact {
  gap: 12px;
  font-size: 17px;
  line-height: 1.45;
}

.numbered--compact li {
  gap: 14px;
}

/* Hero */

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 460px);
  align-items: center;
  gap: clamp(32px, 5vw, 80px);
  padding: clamp(32px, 6vw, 88px) 0 clamp(56px, 8vw, 112px);
}

.hero__content {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.hero__title {
  font-size: clamp(40px, 5.4vw, 72px);
  line-height: 1.03;
  letter-spacing: -0.03em;
  font-weight: 500;
}

.hero__lede {
  font-size: clamp(18px, 1.6vw, 21px);
  line-height: 1.45;
  color: var(--color-muted);
  max-width: 42ch;
}

.hero__dates {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-top: 8px;
}

.date-cards {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.date-card {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 120px;
  padding: 10px 16px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.date-card__label {
  font-size: 12px;
  color: var(--color-muted);
}

.date-card__value {
  font-size: 17px;
  font-weight: 500;
}

.hero__times {
  font-size: 14px;
  line-height: 1.45;
  color: var(--color-muted);
}

.hero__credits {
  font-size: 15px;
  line-height: 1.5;
  color: var(--color-muted);
  max-width: 46ch;
}

/* Sign-up card and form controls */

.signup-card {
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding: clamp(24px, 3vw, 36px);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.signup-card__title {
  font-size: 26px;
  line-height: 1.15;
  font-weight: 500;
  letter-spacing: -0.02em;
}

.signup-card__intro {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 15px;
  line-height: 1.45;
}

.signup-card__proof {
  border-top: 1px solid var(--color-border-soft);
  padding-top: 16px;
  font-size: 14px;
  line-height: 1.45;
  color: var(--color-muted);
}

.signup-form {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.field__label {
  font-size: 14px;
  font-weight: 500;
}

.input {
  width: 100%;
  height: 52px;
  padding: 0 16px;
  font: inherit;
  font-size: 16px;
  color: var(--color-ink);
  background: var(--color-surface);
  border: 1px solid var(--color-input-border);
  border-radius: var(--radius-control);
}

.input::placeholder {
  color: var(--color-placeholder);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  height: 58px;
  padding: 0 30px;
  font: inherit;
  font-size: 19px;
  font-weight: 700;
  color: #ffffff;
  background: var(--color-accent);
  border: 0;
  border-radius: var(--radius-control);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
}

.button:hover {
  color: #ffffff;
  background: var(--color-accent-hover);
}

.button__icon {
  width: 18px;
  height: 18px;
  flex: 0 0 auto;
}

.fineprint {
  font-size: 13px;
  line-height: 1.45;
  color: var(--color-muted);
}

.fineprint a {
  color: var(--color-muted);
}

/* "What you'll learn" intro */

.learn-intro {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
  text-align: center;
  border-top: 1px solid var(--color-border);
  padding-top: clamp(56px, 7vw, 96px);
}

/* Feature rows: figure, arrow, text */

.feature {
  display: grid;
  grid-template-columns: minmax(0, 540px) 32px minmax(0, 1fr);
  align-items: center;
  gap: var(--column-gap);
}

.feature--reverse {
  grid-template-columns: minmax(0, 1fr) 32px minmax(0, 540px);
}

.feature--narrow {
  grid-template-columns: minmax(0, 400px) 32px minmax(0, 1fr);
}

.arrow {
  width: 32px;
  height: 32px;
  flex: 0 0 auto;
  color: var(--color-accent);
}

.arrow--left {
  transform: scaleX(-1);
}

.arrow--down {
  transform: rotate(90deg);
}

/* Panels */

.panel {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 28px 28px 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.panel__caption {
  font-size: 15px;
  font-weight: 500;
}

.chart {
  display: block;
  width: 100%;
  height: auto;
  font-family: var(--font-sans);
}

.chart__accent {
  fill: var(--color-accent);
}

.md-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  font-family: var(--font-mono);
}

.md-card__caption {
  padding: 16px 20px;
  font-size: 12px;
  color: var(--color-muted);
  border-bottom: 1px solid var(--color-border-soft);
}

.md-card__body {
  list-style: none;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px;
  font-size: 13px;
  line-height: 1.6;
}

.md-card__heading {
  font-weight: 500;
}

.md-card__line {
  color: var(--color-muted);
}

.md-card__line--highlight {
  color: var(--color-ink);
  background: var(--color-highlight);
  padding: 8px 10px;
  margin: 0 -10px;
}

.teacher {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.teacher__photo {
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 4 / 5;
  background: var(--color-photo);
  font-size: 14px;
  color: var(--color-muted);
}

.teacher__name {
  display: block;
  font-size: 17px;
  font-weight: 500;
}

.teacher__role {
  display: block;
  font-size: 14px;
  color: var(--color-muted);
}

/* Is this for you? */

.fit {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.fit__card {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: clamp(20px, 3vw, 32px);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.fit__title {
  font-size: 20px;
  font-weight: 500;
}

/* FAQ */

.faq {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(280px, 100%), 1fr));
  gap: 32px 48px;
}

.faq__item {
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-top: 1px solid var(--color-rule);
  padding-top: 20px;
}

.faq__question {
  font-size: 18px;
  font-weight: 500;
}

.faq__answer {
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-muted);
}

/* Closing call to action */

.cta {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
  padding: clamp(36px, 6vw, 80px);
  text-align: center;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.cta__title {
  font-size: clamp(32px, 3.4vw, 48px);
  line-height: 1.06;
  letter-spacing: -0.025em;
  font-weight: 500;
}

.cta__form {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  width: 100%;
  max-width: 580px;
  padding-top: 8px;
}

.cta__form .input {
  flex: 1 1 260px;
  min-width: 0;
  height: 58px;
}

.cta__form .button {
  flex: 1 0 auto;
}

/* Footer */

.site-footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  padding-top: 28px;
  font-size: 13px;
  color: var(--color-muted);
}

.site-footer a {
  color: var(--color-muted);
}

/* Thank-you page */

.thanks {
  max-width: 720px;
  margin: 0 auto;
  padding: clamp(32px, 6vw, 80px) 0 clamp(56px, 8vw, 104px);
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.steps {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 16px;
  counter-reset: step;
}

.step {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: clamp(20px, 3vw, 28px);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  counter-increment: step;
}

.step__title {
  display: flex;
  gap: 14px;
  font-size: 20px;
  font-weight: 500;
}

.step__title::before {
  content: counter(step);
  color: var(--color-numeral);
  font-weight: 400;
}

.step__body {
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-muted);
}

.session {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-top: 14px;
  border-top: 1px solid var(--color-border-soft);
}

.session__name {
  font-size: 16px;
  font-weight: 500;
}

.session__when {
  display: block;
  font-size: 14px;
  font-weight: 400;
  color: var(--color-muted);
}

.session__links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 14px;
}

/* Small screens: stack every row and drop the sideways arrows,
   which only make sense when the figure sits beside the text. */

@media (max-width: 960px) {
  .hero,
  .feature,
  .feature--reverse,
  .feature--narrow {
    grid-template-columns: minmax(0, 1fr);
  }

  .feature .arrow {
    display: none;
  }

  .feature--narrow .teacher {
    max-width: 400px;
  }

  .fit {
    grid-template-columns: minmax(0, 1fr);
  }
}