/* ==========================================================================
   Text as Data 2026 — tada2026.org
   Berkeley Blue #002676 · California Gold #FDB515
   ========================================================================== */

:root {
  --blue: #002676;
  --blue-deep: #001233;
  --blue-night: #011c52;
  --gold: #fdb515;
  --gold-soft: #ffc843;
  --gold-ink: #8a6100; /* accessible gold for small text on light bg */
  --ink: #131f3d;
  --slate: #48546e;
  --cream: #faf8f3;
  --paper: #ffffff;
  --line: rgba(0, 38, 118, 0.1);
  --shadow-sm: 0 1px 3px rgba(0, 18, 51, 0.06), 0 4px 16px rgba(0, 18, 51, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 18, 51, 0.08), 0 16px 40px rgba(0, 18, 51, 0.1);
  --radius: 1rem;
  --font-display: "Fraunces", Georgia, "Times New Roman", serif;
  --font-body: "Source Sans 3", system-ui, -apple-system, "Segoe UI", sans-serif;
  --header-h: 4rem;
}

/* ---------- Base ---------- */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 1rem);
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--ink);
  background: var(--cream);
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
}

h1,
h2,
h3 {
  margin: 0;
  font-family: var(--font-display);
  line-height: 1.15;
  text-wrap: balance;
}

p {
  margin: 0;
}

.container {
  width: min(72rem, 100% - 2.5rem);
  margin-inline: auto;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  z-index: 100;
  padding: 0.75rem 1.25rem;
  background: var(--gold);
  color: var(--blue-deep);
  font-weight: 700;
  border-radius: 0 0 0.5rem 0.5rem;
  text-decoration: none;
}

.skip-link:focus {
  top: 0;
}

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

::selection {
  background: var(--gold);
  color: var(--blue-deep);
}

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(1, 18, 51, 0.88);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: var(--header-h);
}

.brand {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 600;
  color: #fff;
  text-decoration: none;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.brand span {
  color: var(--gold);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-links a {
  position: relative;
  color: rgba(255, 255, 255, 0.78);
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  transition: color 0.2s ease;
}

.nav-links a:hover {
  color: #fff;
}

.nav-links a[aria-current="true"] {
  color: #fff;
}

.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -0.45rem;
  height: 2px;
  border-radius: 999px;
  background: var(--gold);
  transform: scaleX(0);
  transition: transform 0.25s ease;
}

.nav-links a[aria-current="true"]::after,
.nav-links a:hover::after {
  transform: scaleX(1);
}

.menu-toggle {
  display: none;
  padding: 0.5rem;
  border: 0;
  border-radius: 0.5rem;
  background: transparent;
  color: #fff;
  cursor: pointer;
}

.menu-toggle:hover {
  background: rgba(255, 255, 255, 0.1);
}

.menu-toggle .icon-close {
  display: none;
}

.menu-toggle[aria-expanded="true"] .icon-menu {
  display: none;
}

.menu-toggle[aria-expanded="true"] .icon-close {
  display: block;
}

@media (max-width: 47.99rem) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.5rem 1.25rem 1rem;
    background: rgba(1, 18, 51, 0.97);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    visibility: hidden;
    opacity: 0;
    transform: translateY(-0.5rem);
    transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s;
  }

  .nav-links.open {
    visibility: visible;
    opacity: 1;
    transform: translateY(0);
  }

  .nav-links a {
    padding: 0.85rem 0.25rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.07);
  }

  .nav-links a:last-child {
    border-bottom: 0;
  }

  .nav-links a::after {
    display: none;
  }

  .nav-links a[aria-current="true"] {
    color: var(--gold);
  }
}

/* ---------- Hero ---------- */

.hero {
  position: relative;
  overflow: hidden;
  color: #fff;
  background:
    radial-gradient(55rem 30rem at 88% -12%, rgba(253, 181, 21, 0.16), transparent 62%),
    radial-gradient(42rem 26rem at -8% 108%, rgba(64, 120, 255, 0.18), transparent 60%),
    linear-gradient(158deg, var(--blue-deep) 0%, var(--blue-night) 48%, var(--blue) 100%);
  padding-block: clamp(4.5rem, 10vw, 7.5rem);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cg fill='%23ffffff' fill-opacity='0.045' font-family='Courier New,monospace' font-size='17'%3E%3Ctext x='14' y='40'%3E%7B%3C/text%3E%3Ctext x='196' y='66'%3Etext%3C/text%3E%3Ctext x='84' y='118'%3E%5B%5B%3C/text%3E%3Ctext x='236' y='160'%3E%7D%3C/text%3E%3Ctext x='30' y='206'%3Edata%3C/text%3E%3Ctext x='168' y='238'%3E%3B%3C/text%3E%3Ctext x='108' y='286'%3E%5D%5D%3C/text%3E%3Ctext x='250' y='288'%3E%2F%2F%3C/text%3E%3C/g%3E%3C/svg%3E");
}

.hero .container {
  position: relative;
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--gold);
}

.hero-eyebrow::before {
  content: "";
  width: 2.25rem;
  height: 2px;
  background: var(--gold);
  border-radius: 999px;
}

.hero h1 {
  max-width: 16ch;
  font-size: clamp(2.75rem, 7.5vw, 4.75rem);
  font-weight: 700;
  letter-spacing: -0.015em;
  margin-bottom: 1.5rem;
}

.hero h1 em {
  font-style: italic;
  color: var(--gold);
}

.hero-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 1.75rem;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.45rem 1rem;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.16);
  background: rgba(255, 255, 255, 0.07);
  color: #e4ebff;
  font-size: 0.92rem;
  font-weight: 600;
}

.chip svg {
  width: 1rem;
  height: 1rem;
  color: var(--gold);
  flex-shrink: 0;
}

.chip--gold {
  border-color: rgba(253, 181, 21, 0.4);
  background: rgba(253, 181, 21, 0.12);
  color: var(--gold-soft);
}

.hero-intro {
  font-size: clamp(1.0625rem, 1.5vw, 1.1875rem);
  line-height: 1.75;
  color: rgba(228, 235, 255, 0.88);
  text-wrap: pretty;
  margin-bottom: 2.25rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-bottom: 3rem;
}

.hero-host {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  padding-top: 1.75rem;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.hero-host span {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: rgba(228, 235, 255, 0.55);
}

.hero-host img {
  width: clamp(170px, 30vw, 210px);
  height: auto;
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.7rem;
  border-radius: 0.65rem;
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  text-decoration: none;
  transition: background 0.2s ease, color 0.2s ease, transform 0.15s ease, box-shadow 0.2s ease;
}

.btn:active {
  transform: translateY(1px);
}

.btn svg {
  width: 1.05rem;
  height: 1.05rem;
  flex-shrink: 0;
}

.btn-gold {
  background: var(--gold);
  color: var(--blue-deep);
  box-shadow: 0 6px 20px rgba(253, 181, 21, 0.25);
}

.btn-gold:hover {
  background: var(--gold-soft);
  transform: translateY(-2px);
  box-shadow: 0 10px 26px rgba(253, 181, 21, 0.32);
}

.btn-ghost {
  border: 1.5px solid rgba(255, 255, 255, 0.35);
  color: #fff;
  background: transparent;
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.6);
  transform: translateY(-2px);
}

.btn-blue {
  background: var(--blue);
  color: #fff;
}

.btn-blue:hover {
  background: var(--blue-night);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.btn-outline {
  border: 1.5px solid rgba(0, 38, 118, 0.3);
  color: var(--blue);
  background: transparent;
}

.btn-outline:hover {
  background: var(--blue);
  color: #fff;
  transform: translateY(-2px);
}

/* ---------- Sections ---------- */

.section {
  padding-block: clamp(4rem, 8vw, 6.25rem);
}

.section--paper {
  background: var(--paper);
  border-block: 1px solid var(--line);
}

.section-head {
  max-width: 46rem;
  margin-bottom: clamp(2.25rem, 5vw, 3.25rem);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  margin-bottom: 0.9rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--gold-ink);
}

.eyebrow::before {
  content: "";
  width: 2rem;
  height: 2px;
  background: var(--gold);
  border-radius: 999px;
}

.section-head h2 {
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  font-weight: 600;
  color: var(--blue);
}

.section-head .lede {
  margin-top: 0.9rem;
  font-size: 1.1rem;
  color: var(--slate);
  text-wrap: pretty;
}

/* ---------- Key dates ---------- */

.dates-grid {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
}

.date-card {
  position: relative;
  padding: 1.9rem 1.9rem 1.75rem;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.date-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.date-card .month {
  display: block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--gold-ink);
  margin-bottom: 0.15rem;
}

.date-card .day {
  display: block;
  font-family: var(--font-display);
  font-size: 3.4rem;
  font-weight: 700;
  line-height: 1;
  color: var(--blue);
  margin-bottom: 0.9rem;
}

.date-card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 0.4rem;
}

.date-card p {
  font-size: 0.97rem;
  color: var(--slate);
}

.date-card--accent {
  background: linear-gradient(150deg, var(--blue-night), var(--blue));
  border-color: transparent;
}

.date-card--accent .month {
  color: var(--gold);
}

.date-card--accent .day {
  color: var(--gold);
}

.date-card--accent h3 {
  color: #fff;
}

.date-card--accent p {
  color: rgba(228, 235, 255, 0.82);
}

.dates-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  margin-top: 2rem;
}

.link-quiet {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  color: var(--blue);
  font-weight: 700;
  text-decoration: none;
  border-bottom: 2px solid rgba(253, 181, 21, 0.6);
  padding-bottom: 0.1rem;
  transition: border-color 0.2s ease;
}

.link-quiet:hover {
  border-color: var(--gold);
}

.link-quiet svg {
  width: 1rem;
  height: 1rem;
  color: var(--gold-ink);
}

/* ---------- Call for presentations ---------- */

.call-grid {
  display: grid;
  gap: 2.5rem;
  align-items: start;
}

@media (min-width: 56rem) {
  .call-grid {
    grid-template-columns: 1.25fr 0.85fr;
    gap: 4rem;
  }
}

.check-list {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
}

.check-list li {
  position: relative;
  padding: 0.35rem 0 0.35rem 2.6rem;
  margin-bottom: 0.85rem;
  color: var(--ink);
  font-size: 1.05rem;
}

.check-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0.35rem;
  display: grid;
  place-items: center;
  width: 1.75rem;
  height: 1.75rem;
  border-radius: 50%;
  background: rgba(253, 181, 21, 0.2);
  color: var(--gold-ink);
  font-size: 0.9rem;
  font-weight: 800;
}

.badge {
  display: inline-block;
  margin-left: 0.4rem;
  padding: 0.1rem 0.6rem;
  border-radius: 999px;
  background: rgba(0, 38, 118, 0.08);
  color: var(--blue);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  vertical-align: middle;
}

.call-card {
  padding: 2rem;
  background: linear-gradient(150deg, var(--blue-night), var(--blue));
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  color: #fff;
}

.call-card .label {
  display: block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 0.35rem;
}

.call-card .big-date {
  font-family: var(--font-display);
  font-size: 2.1rem;
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: 1.1rem;
}

.call-card .note {
  font-size: 0.97rem;
  color: rgba(228, 235, 255, 0.85);
}

/* ---------- Venue & travel ---------- */

.venue-grid {
  display: grid;
  gap: 1.25rem;
}

@media (min-width: 56rem) {
  .venue-grid {
    grid-template-columns: 1.15fr 0.85fr;
  }
}

.venue-card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 2.25rem;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

.venue-card .icon-ring {
  margin-bottom: 1.1rem;
}

.venue-card h3 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--blue);
  margin-bottom: 0.35rem;
}

.venue-card .campus {
  font-weight: 700;
  color: var(--gold-ink);
  font-size: 0.95rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

.venue-card address {
  font-style: normal;
  color: var(--slate);
  line-height: 1.6;
  margin-bottom: 1.4rem;
}

.venue-card .btn {
  align-self: flex-start;
}

.travel-stack {
  display: grid;
  gap: 1.25rem;
  align-content: start;
}

.travel-card {
  display: flex;
  gap: 1.15rem;
  padding: 1.6rem;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.travel-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.icon-ring {
  display: grid;
  place-items: center;
  width: 3rem;
  height: 3rem;
  flex-shrink: 0;
  border-radius: 0.85rem;
  background: rgba(253, 181, 21, 0.16);
  color: var(--blue);
}

.icon-ring svg {
  width: 1.4rem;
  height: 1.4rem;
}

.travel-card h3 {
  font-family: var(--font-body);
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 0.3rem;
}

.travel-card p {
  font-size: 0.97rem;
  color: var(--slate);
}

/* ---------- Contact band ---------- */

.contact-band {
  background:
    radial-gradient(40rem 20rem at 100% 0%, rgba(253, 181, 21, 0.14), transparent 60%),
    linear-gradient(150deg, var(--blue-deep), var(--blue));
  color: #fff;
  text-align: center;
  padding-block: clamp(3.5rem, 7vw, 5rem);
}

.contact-band h2 {
  font-size: clamp(1.7rem, 3.5vw, 2.2rem);
  font-weight: 600;
  margin-bottom: 0.6rem;
}

.contact-band p {
  color: rgba(228, 235, 255, 0.8);
  margin-bottom: 1.75rem;
}

/* ---------- Footer ---------- */

.site-footer {
  background: var(--blue-deep);
  color: rgba(228, 235, 255, 0.7);
  padding-block: 1.75rem;
  font-size: 0.92rem;
}

.site-footer .container {
  text-align: center;
}

/* ---------- Reveal animations ---------- */

.js .reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.js .reveal.visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }

  .js .reveal {
    opacity: 1;
    transform: none;
  }
}