:root {
  --bg: #000;
  --surface: #161617;
  --border: #2a2a2c;
  --text: #f5f5f7;
  --text-secondary: #a1a1a6;
  --link: #2997ff;
  --font: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-display: var(--font);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }

html { scroll-behavior: smooth; scroll-padding-top: 48px; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.47;
  letter-spacing: -0.022em;
  -webkit-font-smoothing: antialiased;
  /* Keeps the footer at the bottom of the window on short pages */
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}
main { flex: 1; }

a { color: var(--link); text-decoration: none; }
code { font-family: ui-monospace, "SF Mono", Menlo, monospace; font-size: 0.9em; }
a:hover { text-decoration: underline; }


.container { max-width: 980px; margin: 0 auto; padding: 0 22px; }
.narrow { max-width: 692px; }
.center { text-align: center; }

/* Nav */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(22, 22, 23, 0.8);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
}
.nav-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 22px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-name { color: var(--text); font-size: 15px; font-weight: 600; }
.nav-links { display: flex; gap: 28px; list-style: none; }
.nav-links a { color: var(--text); opacity: 0.8; font-size: 12px; }
.nav-name:hover, .nav-links a:hover { text-decoration: none; opacity: 1; }
.nav-links a[aria-current="page"] { opacity: 1; }

/* Hero */
.hero {
  max-width: 820px;
  margin: 0 auto;
  padding: 120px 22px 100px;
  text-align: center;
}
.hero h1 {
  font-family: var(--font-display);
  font-size: 80px;
  line-height: 1.05;
  font-weight: 600;
  letter-spacing: -0.015em;
  margin: 8px 0 20px;
}
.hero-page { max-width: 980px; }
.hero-page h1 { font-size: 64px; line-height: 1.0625; }
.lede {
  font-size: 24px;
  line-height: 1.33;
  color: var(--text-secondary);
  letter-spacing: 0.009em;
}
.hero .lede { max-width: 640px; margin: 0 auto; }
.hero-links {
  margin-top: 36px;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 32px;
}

.eyebrow {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: -0.016em;
}

.button {
  display: inline-block;
  background: #0071e3;
  color: #fff;
  font-size: 17px;
  padding: 11px 22px;
  border-radius: 980px;
}
.button:hover { background: #0077ed; text-decoration: none; }

.text-link { font-size: 17px; }

/* Sections */
.section { padding: 100px 0; border-top: 1px solid var(--border); }
.section h2 {
  font-family: var(--font-display);
  font-size: 48px;
  line-height: 1.08;
  font-weight: 600;
  letter-spacing: -0.003em;
  margin-bottom: 32px;
}
#about p, #sessions p { font-size: 19px; line-height: 1.47; color: var(--text-secondary); }
#about p + p, #sessions p + p { margin-top: 20px; }
#about strong { color: var(--text); font-weight: 600; }

/* Projects */
.projects {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.feature {
  background: var(--surface);
  border-radius: 18px;
  padding: 48px;
}
.feature-text { height: 100%; display: flex; flex-direction: column; }
.feature-text .links { margin-top: auto; padding-top: 24px; }
.feature h3 {
  font-family: var(--font-display);
  font-size: 40px;
  font-weight: 600;
  line-height: 1.1;
  margin: 6px 0 14px;
}
.feature p:not(.eyebrow) { font-size: 17px; color: var(--text-secondary); }
.links { display: flex; flex-wrap: wrap; gap: 12px 28px; }
.status { font-size: 17px; color: #86868b; }


.section-text { font-size: 19px; color: var(--text-secondary); }
.section-text + .section-text { margin-top: 20px; }
.section-intro { font-size: 19px; color: var(--text-secondary); margin: -16px 0 32px; }
.feature p:not(.eyebrow) + p:not(.eyebrow) { margin-top: 12px; }

/* Tutoring: reasons */
.reasons {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
}
.reasons h3 { font-size: 24px; font-weight: 600; line-height: 1.17; margin-bottom: 10px; }
.reasons p { color: var(--text-secondary); }

/* Activities */
.list-title { font-size: 24px; font-weight: 600; line-height: 1.17; padding: 24px 0 8px; }
.results { list-style: none; }
.list-card { background: var(--surface); border-radius: 18px; padding: 0 24px; margin-top: 40px; }
.list-card + .list-card { margin-top: 20px; }
.results li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding: 16px 0;
}
.results li + li { border-top: 1px solid var(--border); }
.result-name { font-weight: 600; }
.result-detail { color: var(--text-secondary); }
.result-year { color: #86868b; white-space: nowrap; }
.result-link { white-space: nowrap; }

/* Sign-up form */
.hero-short { padding-bottom: 48px; }
.form-section { padding: 0 0 100px; }
.form-container { max-width: 560px; }
/* 16px matches gridRowSpacing for the Stripe fields in pay.html */
.form { display: flex; flex-direction: column; gap: 16px; }
.field { border: 0; min-width: 0; }
.field label, .field legend {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 8px;
}
.field input, .field textarea {
  width: 100%;
  font: inherit;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
  outline: none;
  transition: border-color 0.15s;
}
.field ::placeholder { color: #6e6e73; }
.field input:focus, .field textarea:focus { border-color: #0071e3; }
.field textarea { resize: vertical; display: block; }

.choices { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.field .choice { position: relative; font-size: 17px; font-weight: 400; margin: 0; }
.field .choice input { position: absolute; top: 0; left: 0; width: 1px; height: 1px; opacity: 0; pointer-events: none; }
.choice span {
  display: block;
  text-align: center;
  padding: 14px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  cursor: pointer;
  transition: border-color 0.15s;
}
.choice input:checked + span { border-color: #0071e3; box-shadow: inset 0 0 0 1px #0071e3; }
.choice input:focus-visible + span { outline: 2px solid #0071e3; outline-offset: 2px; }

.trap { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }

.form .button { align-self: center; margin-top: 8px; border: 0; font: inherit; cursor: pointer; }
.form .button:disabled { opacity: 0.6; cursor: default; }
.form-error, .form-success { text-align: center; }
.form-error { color: #ff6961; }
.form-success { color: #30d158; }
.form-back { text-align: center; margin-top: 32px; }
.form-note { text-align: center; font-size: 14px; color: #86868b; margin-top: -8px; }
.field .optional { font-weight: 400; color: var(--text-secondary); }
.field-hint { font-size: 14px; color: #86868b; margin-top: 8px; }

/* Pay button, or the Apple Pay button in its place */
.actions { display: flex; flex-direction: column; align-items: center; margin-top: 8px; }
.actions .button { margin-top: 0; }
#express { width: 100%; max-width: 240px; }

.amount { position: relative; }
.amount span {
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  pointer-events: none;
}
.field .amount input { padding-left: 32px; }

/* Contact */
#contact .lede { margin-bottom: 32px; }
.social {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 32px;
  margin-top: 0;
}

/* Footer */
.footer {
  border-top: 1px solid var(--border);
  padding: 20px 0 32px;
  font-size: 12px;
  color: #86868b;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 24px;
}
.footer-links { list-style: none; display: flex; flex-wrap: wrap; gap: 8px 20px; }
.footer-links a { color: var(--text-secondary); }

/* Small screens */
@media (max-width: 734px) {
  .hero { padding: 80px 16px 72px; }
  .hero h1, .hero-page h1 { font-size: 40px; }
  .lede { font-size: 19px; }
  .section { padding: 72px 0; }
  .section h2 { font-size: 32px; margin-bottom: 24px; }
  #about p, #sessions p { font-size: 17px; }
  .container, .nav-inner { padding: 0 16px; }
  .nav-links { gap: 20px; }
  .projects, .reasons { grid-template-columns: 1fr; }
  .form-section { padding-bottom: 72px; }
  .reasons { gap: 32px; }
  .feature { padding: 32px 24px; }
  .feature h3 { font-size: 32px; }
  .hero-links { flex-direction: column; gap: 20px; }
}