:root {
  --river: #0b5360;
  --river-deep: #063b43;
  --green: #244b39;
  --leaf: #5d8865;
  --sand: #e8d9bd;
  --stone: #f6f2ea;
  --ink: #18302e;
  --mist: #dbe8e5;
  --white: #fffefa;
  --line: rgba(24, 48, 46, 0.18);
  --serif: Georgia, 'Times New Roman', serif;
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--stone); color: var(--ink); font-family: var(--sans); font-size: 16px; line-height: 1.6; }
a { color: inherit; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }

.skip-link { position: fixed; z-index: 20; top: -4rem; left: 1rem; padding: .7rem 1rem; background: var(--white); color: var(--river-deep); border-radius: .25rem; transition: top .2s ease; }
.skip-link:focus { top: 1rem; }

.site-header { min-height: 86px; display: flex; align-items: center; justify-content: space-between; gap: 1.5rem; max-width: 1440px; margin: auto; padding: 1rem clamp(1.25rem, 4vw, 4.5rem); }
.brand { display: inline-flex; align-items: center; gap: .7rem; text-decoration: none; flex-shrink: 0; }
.brand-mark { display: grid; place-items: center; width: 42px; height: 42px; border: 1px solid currentColor; border-radius: 50%; font-size: .62rem; letter-spacing: .08em; font-weight: 800; position: relative; overflow: hidden; }
.brand-mark::after { content: ''; position: absolute; width: 135%; height: 42%; border: 1px solid currentColor; border-radius: 50%; transform: rotate(-20deg); bottom: -7px; opacity: .75; }
.brand-copy { display: grid; line-height: 1.1; }
.brand-copy strong { font-family: var(--serif); font-size: 1rem; letter-spacing: -.02em; }
.brand-copy small { font-size: .58rem; font-weight: 700; letter-spacing: .13em; text-transform: uppercase; margin-top: .25rem; }
.site-header nav { display: flex; align-items: center; justify-content: flex-end; gap: clamp(.8rem, 2vw, 2rem); font-size: .82rem; font-weight: 700; }
.site-header nav > a { text-decoration: none; }
.site-header nav > a:not(.nav-cta) { position: relative; }
.site-header nav > a:not(.nav-cta)::after { content: ''; height: 1px; width: 0; background: var(--river); position: absolute; left: 0; bottom: -.3rem; transition: width .2s ease; }
.site-header nav > a:not(.nav-cta):hover::after, .site-header nav > a:not(.nav-cta):focus-visible::after, .site-header nav > a[aria-current='page']::after { width: 100%; }
.nav-cta { padding: .72rem 1rem; border: 1px solid var(--river); color: var(--river-deep); border-radius: .2rem; }

.hero { max-width: 1440px; margin: 0 auto; padding: clamp(1.75rem, 4vw, 4.5rem) clamp(1.25rem, 4vw, 4.5rem) clamp(3.5rem, 7vw, 7rem); display: grid; grid-template-columns: minmax(0, .82fr) minmax(390px, 1.18fr); align-items: center; gap: clamp(2rem, 6vw, 8rem); }
.hero-copy { padding: clamp(1rem, 2vw, 2rem) 0; max-width: 560px; }
.eyebrow { display: flex; align-items: center; gap: .55rem; color: var(--river); font-size: .72rem; line-height: 1.3; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
.eyebrow > span { display: inline-block; width: 25px; height: 1px; background: currentColor; }
.eyebrow-light { color: var(--sand); }
h1, h2, h3, p { margin-top: 0; }
h1 { color: var(--river-deep); font-family: var(--serif); font-size: clamp(3rem, 5.2vw, 6rem); font-weight: 400; line-height: .96; letter-spacing: -.07em; margin: .9rem 0 1.5rem; }
h1 em { color: var(--green); font-weight: inherit; }
.hero-intro { max-width: 480px; font-size: clamp(1rem, 1.4vw, 1.17rem); color: #405653; }
.hero-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 1.2rem 1.6rem; margin-top: 2rem; }
.button { display: inline-flex; justify-content: center; align-items: center; gap: 1.2rem; padding: .95rem 1.2rem; min-height: 50px; border: 1px solid transparent; border-radius: .18rem; font-weight: 800; text-decoration: none; transition: transform .2s ease, background .2s ease, border-color .2s ease; }
.button:hover { transform: translateY(-2px); }
.button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible { outline: 3px solid #d69b3c; outline-offset: 3px; }
.button-primary { background: var(--river); color: var(--white); }
.button-primary:hover { background: var(--river-deep); }
.text-link { color: var(--river-deep); font-weight: 800; text-underline-offset: .3em; }
.hero-image-wrap { width: 100%; aspect-ratio: 16 / 9; position: relative; isolation: isolate; }
.hero-image-wrap::before { content: ''; z-index: -1; position: absolute; left: -9%; bottom: -6%; width: 61%; height: 44%; border-radius: 50%; border: 1px solid rgba(11, 83, 96, .32); transform: rotate(-15deg); }
.hero-image { display: block; width: 100%; height: 100%; object-fit: cover; object-position: center; border-radius: 2px; filter: saturate(.88) contrast(.98); }
.hero-image-wrap::after { content: ''; position: absolute; inset: 0; pointer-events: none; background: linear-gradient(145deg, rgba(6, 59, 67, .12), transparent 50%); }
.hero-date { position: absolute; display: grid; place-content: center; text-align: center; z-index: 1; right: -2.2rem; top: 2.2rem; width: 134px; height: 134px; border-radius: 50%; background: var(--sand); color: var(--river-deep); box-shadow: 0 10px 30px rgba(16, 45, 42, .17); font-size: .66rem; font-weight: 800; letter-spacing: .1em; line-height: 1.1; text-transform: uppercase; }
.hero-date strong { display: block; font-family: var(--serif); font-size: 3.15rem; font-weight: 400; letter-spacing: -.08em; line-height: .85; padding: .12rem 0 .18rem; }
.image-credit { position: absolute; z-index: 1; left: 1.1rem; bottom: 1rem; margin: 0; color: var(--white); font-size: .76rem; font-weight: 700; text-shadow: 0 1px 10px rgba(0,0,0,.65); }

.section-shell { max-width: 1280px; margin: auto; padding-left: clamp(1.25rem, 4vw, 4.5rem); padding-right: clamp(1.25rem, 4vw, 4.5rem); }
.intro-section { display: grid; grid-template-columns: 120px minmax(250px, 1.15fr) minmax(260px, .85fr); column-gap: clamp(1.5rem, 5vw, 6rem); padding-top: 5.8rem; padding-bottom: 6rem; }
.section-label { display: flex; flex-direction: column; align-items: flex-start; gap: .65rem; color: var(--river); font-size: .68rem; font-weight: 800; letter-spacing: .12em; line-height: 1.25; text-transform: uppercase; }
.section-label > span:first-child { display: grid; place-items: center; width: 30px; height: 30px; border: 1px solid currentColor; border-radius: 50%; font-size: .63rem; }
.section-label-light { color: var(--sand); }
.intro-main h2, .take-part-heading h2, .registration-copy h2, .contact-copy h2 { font-family: var(--serif); color: var(--green); font-size: clamp(2.25rem, 4.2vw, 4.2rem); font-weight: 400; letter-spacing: -.055em; line-height: 1; margin: .8rem 0 0; }
.intro-copy { padding-top: 2rem; color: #405653; }
.intro-copy p + p { margin-top: 1.25rem; }

.route-section { background: var(--river-deep); color: var(--white); padding: clamp(4.5rem, 8vw, 8rem) 0; position: relative; overflow: hidden; }
.route-section::before { content: ''; position: absolute; opacity: .14; width: 980px; height: 340px; border: 1px solid var(--sand); border-radius: 50%; right: -260px; top: 50px; transform: rotate(-17deg); }
.route-section .section-shell { display: grid; grid-template-columns: minmax(300px, .85fr) minmax(310px, 1.15fr); gap: clamp(3rem, 10vw, 10rem); position: relative; }
.route-heading h2 { font-family: var(--serif); font-size: clamp(2.7rem, 4.5vw, 4.7rem); font-weight: 400; letter-spacing: -.06em; line-height: .97; margin: 1rem 0 1.5rem; }
.route-heading > p:last-child { color: #d1e3de; max-width: 460px; }
.route-stops { list-style: none; border-left: 1px solid rgba(232, 217, 189, .55); padding: .1rem 0 0 3rem; margin: 1.25rem 0 0; display: grid; gap: 2.4rem; }
.route-stops li { position: relative; }
.route-number { position: absolute; left: -4rem; top: .1rem; display: grid; place-items: center; width: 2rem; height: 2rem; border-radius: 50%; background: var(--sand); color: var(--river-deep); font-size: .65rem; font-weight: 900; }
.stop-type { margin-bottom: .2rem; color: var(--sand); font-size: .67rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
.route-stops h3 { font-family: var(--serif); font-size: 1.7rem; font-weight: 400; letter-spacing: -.03em; line-height: 1.1; margin: 0; }
.route-stops p:last-child { margin: .25rem 0 0; color: #c9ded9; font-size: .91rem; }

.sponsor-showcase { overflow: hidden; padding: clamp(4.25rem, 7vw, 6.5rem) 0 clamp(3.5rem, 6vw, 5.5rem); background: var(--white); border-top: 1px solid rgba(24,48,46,.1); border-bottom: 1px solid rgba(24,48,46,.1); }
.sponsor-heading-centred { max-width: 760px; text-align: center; }
.sponsor-heading-centred .eyebrow { justify-content: center; }
.sponsor-heading h2 { margin: .8rem 0 1rem; color: var(--river-deep); font-family: var(--serif); font-size: clamp(2.4rem, 4vw, 4.4rem); font-weight: 400; letter-spacing: -.055em; line-height: 1; }
.sponsor-heading > p:last-child { max-width: 550px; margin: 0 auto; color: #586a65; }
.sponsor-logo-carousel { position: relative; overflow: hidden; margin-top: clamp(2rem, 4vw, 3.5rem); padding: .85rem 0; mask-image: linear-gradient(to right, transparent, #000 7%, #000 93%, transparent); }
.sponsor-logo-carousel::before, .sponsor-logo-carousel::after { content: ''; position: absolute; z-index: 2; top: 0; bottom: 0; width: min(9vw, 120px); pointer-events: none; }
.sponsor-logo-carousel::before { left: 0; background: linear-gradient(90deg, var(--white), transparent); }
.sponsor-logo-carousel::after { right: 0; background: linear-gradient(-90deg, var(--white), transparent); }
.sponsor-track { display: flex; width: max-content; animation: sponsor-marquee 24s linear infinite; }
.sponsor-set { flex: 0 0 max(100vw, 700px); width: max(100vw, 700px); display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); align-items: center; justify-items: center; gap: clamp(1rem, 3vw, 3.5rem); padding: 0 clamp(1.5rem, 5vw, 7rem); }
.sponsor-logo-carousel:hover .sponsor-track, .sponsor-logo-carousel:focus-within .sponsor-track { animation-play-state: paused; }
.sponsor-logo { display: grid; place-items: center; width: clamp(118px, 11vw, 164px); aspect-ratio: 1; border: 1px solid rgba(6,59,67,.17); border-radius: 50%; box-shadow: 0 10px 26px rgba(16,45,42,.08); overflow: hidden; text-decoration: none; transition: transform .2s ease, box-shadow .2s ease; }
.sponsor-logo:hover { transform: translateY(-4px); box-shadow: 0 16px 34px rgba(16,45,42,.16); }
.sponsor-ai-logo { background: #082f38; }
.sponsor-ai-logo-mark { display: flex; align-items: center; gap: .25rem; color: #56ebe3; font-weight: 800; letter-spacing: -.06em; line-height: .8; }
.sponsor-ai-logo-mark strong { font-size: clamp(2.75rem, 5vw, 4.4rem); font-weight: 900; }
.sponsor-ai-logo-mark small { font-size: clamp(.6rem, 1.15vw, .86rem); font-weight: 800; letter-spacing: .08em; line-height: 1.15; }
.sponsor-twbi-logo { padding: 6%; background: #153f38; }
.sponsor-twbi-logo img { width: 100%; height: 100%; object-fit: contain; }
@keyframes sponsor-marquee { to { transform: translateX(-50%); } }

.take-part { display: grid; grid-template-columns: 120px minmax(0, 1fr); column-gap: clamp(1.5rem, 5vw, 6rem); padding-top: 6.5rem; padding-bottom: 6.5rem; }
.take-part-heading { margin-bottom: 2.5rem; }
.participant-list { grid-column: 2; display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.participant-card { min-height: 280px; background: var(--white); padding: 1.6rem; border-top: 3px solid var(--river); position: relative; box-shadow: 0 8px 25px rgba(16, 45, 42, .04); transition: transform .2s ease, box-shadow .2s ease; }
.participant-card:hover { transform: translateY(-4px); box-shadow: 0 14px 32px rgba(16, 45, 42, .1); }
.participant-icon { display: block; color: var(--leaf); font-family: var(--serif); font-size: 2.1rem; line-height: 1; }
.card-number { position: absolute; right: 1.6rem; top: 1.7rem; color: #a6b5af; font-size: .68rem; font-weight: 800; letter-spacing: .1em; }
.participant-card h3 { color: var(--river-deep); font-family: var(--serif); font-size: 1.8rem; font-weight: 400; letter-spacing: -.04em; line-height: 1.1; margin: 2.5rem 0 .85rem; }
.participant-card p:last-child { margin-bottom: 0; color: #50635e; font-size: .9rem; }
.participation-note { grid-column: 2; margin: 1.5rem 0 0; color: #52635e; font-size: .88rem; }

.registration-section, .contact-section { background: var(--green); color: var(--white); padding: clamp(4.5rem, 8vw, 8rem) 0; }
.registration-inner, .contact-layout { display: grid; grid-template-columns: minmax(280px, .78fr) minmax(360px, 1.22fr); gap: clamp(2.5rem, 8vw, 8rem); align-items: start; }
.registration-copy h2, .contact-copy h2 { color: var(--white); margin-top: 1rem; }
.registration-copy > p:not(.eyebrow), .contact-copy > p:not(.eyebrow) { color: #d7e5d7; max-width: 430px; font-size: 1.03rem; }
.contact-copy a { color: var(--sand); font-weight: 800; text-underline-offset: .2em; }
.registration-callout { display: flex; gap: .7rem; margin-top: 2rem; max-width: 450px; padding-top: 1.1rem; border-top: 1px solid rgba(232,217,189,.42); color: #e0ecdf; font-size: .84rem; }
.registration-callout span { color: var(--sand); font-size: .6rem; padding-top: .35rem; }
.registration-callout p { margin: 0; }
.interest-form { background: var(--white); color: var(--ink); padding: clamp(1.5rem, 4vw, 2.8rem); box-shadow: 0 25px 55px rgba(0,0,0,.18); }
.form-intro { display: flex; justify-content: space-between; gap: 1rem; padding-bottom: 1.1rem; margin-bottom: 1.35rem; border-bottom: 1px solid var(--line); }
.form-intro p { margin: 0; color: var(--river-deep); font-family: var(--serif); font-size: 1.25rem; line-height: 1.1; }
.form-intro span { color: #60736e; font-size: .65rem; font-weight: 800; letter-spacing: .1em; text-align: right; text-transform: uppercase; }
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem 1.1rem; }
.field { display: grid; gap: .35rem; }
.field-full { grid-column: 1 / -1; }
.field label, .check-field label { font-size: .77rem; font-weight: 800; line-height: 1.35; }
.field label span:not(.optional), .check-field label span { color: #9c4b2f; }
.optional { color: #687771; font-size: .68rem; font-weight: 600; }
.field input, .field select, .field textarea { width: 100%; border: 1px solid #b9c6c0; border-radius: 1px; background: #fffefa; color: var(--ink); padding: .7rem .75rem; transition: border-color .2s ease, box-shadow .2s ease; }
.field textarea { resize: vertical; }
.field input:focus, .field select:focus, .field textarea:focus { border-color: var(--river); box-shadow: 0 0 0 3px rgba(11,83,96,.12); outline: 0; }
.field input[aria-invalid='true'], .field select[aria-invalid='true'], .field textarea[aria-invalid='true'] { border-color: #b44932; }
.honeypot { display: none; }
.check-field { display: grid; grid-template-columns: 18px 1fr; gap: .65rem; margin: 1.35rem 0; align-items: start; }
.check-field input { width: 18px; height: 18px; margin: .1rem 0 0; accent-color: var(--river); }
.button-submit { width: 100%; border-color: var(--river); background: var(--river); color: var(--white); }
.button-submit:hover { background: var(--river-deep); }
.button-submit:disabled { cursor: wait; opacity: .7; transform: none; }
.form-status { min-height: 1.4em; margin: .9rem 0 0; font-size: .87rem; font-weight: 700; }
.form-status[data-state='success'] { color: #1f6b42; }
.form-status[data-state='error'] { color: #a33e2a; }
.form-footnote { margin: .9rem 0 0; color: #62736e; font-size: .72rem; line-height: 1.45; }

.contact-hero { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(240px, .55fr); gap: clamp(2rem, 8vw, 8rem); align-items: end; padding-top: clamp(3.5rem, 7vw, 7rem); padding-bottom: clamp(4rem, 7vw, 6.5rem); }
.contact-intro { max-width: 600px; color: #405653; font-size: 1.1rem; }
.contact-direct { align-self: stretch; border-left: 2px solid var(--river); padding: 1.25rem 0 1.25rem 1.4rem; }
.contact-direct p { color: #52635e; font-size: .9rem; }
.contact-direct a { display: inline-block; margin: .1rem 0 .7rem; color: var(--river-deep); font-family: var(--serif); font-size: clamp(1.4rem, 2.5vw, 2rem); font-weight: 700; text-decoration-thickness: 1px; text-underline-offset: .2em; }
.contact-label { margin-bottom: .2rem; color: var(--river); font-size: .69rem; font-weight: 800; letter-spacing: .13em; text-transform: uppercase; }

.site-footer { display: grid; grid-template-columns: 1fr auto auto auto; align-items: center; gap: 1.5rem; padding-top: 2.2rem; padding-bottom: 2.2rem; font-size: .78rem; color: #52645e; }
.brand-footer { color: var(--river-deep); }
.site-footer p { margin: 0; }
.footer-link { color: var(--river-deep); font-weight: 800; text-underline-offset: .3em; }
.proposed-domain { font-weight: 800; color: var(--river); }
.proposed-domain span { color: #76837f; font-weight: 500; }

@media (max-width: 900px) {
  .site-header nav > a:not(.nav-cta) { display: none; }
  .hero { grid-template-columns: 1fr; }
  .hero-copy { max-width: 640px; }
  .hero-date { right: 1.2rem; }
  .intro-section { grid-template-columns: 90px 1fr; }
  .intro-copy { grid-column: 2; padding-top: 0; max-width: 650px; }
  .route-section .section-shell { grid-template-columns: 1fr; }
  .take-part { grid-template-columns: 90px 1fr; }
  .participant-list { grid-template-columns: repeat(3, 1fr); }
  .registration-inner, .contact-layout { grid-template-columns: 1fr; }
  .registration-copy, .contact-copy { max-width: 680px; }
  .contact-hero { grid-template-columns: 1fr; max-width: 700px; }
  .contact-direct { max-width: 460px; }
  .site-footer { grid-template-columns: 1fr auto; }
  .site-footer .proposed-domain { grid-column: 1 / -1; }
}

@media (max-width: 620px) {
  body { font-size: 15px; }
  .site-header { min-height: 70px; gap: .5rem; padding: .8rem 1rem; }
  .site-header nav { gap: 0; font-size: .72rem; }
  .nav-cta { padding: .58rem .65rem; white-space: nowrap; }
  .brand { gap: .45rem; }
  .brand-mark { width: 36px; height: 36px; font-size: .54rem; }
  .brand-copy strong { font-size: .86rem; }
  .brand-copy small { font-size: .5rem; }
  .hero { padding-top: 1rem; padding-bottom: 4rem; }
  h1 { font-size: clamp(3.05rem, 15vw, 4.55rem); }
  .hero-image-wrap, .hero-image { min-height: 0; }
  .hero-date { top: .75rem; right: .75rem; width: 88px; height: 88px; font-size: .52rem; }
  .hero-date strong { font-size: 2.1rem; }
  .image-credit { left: .75rem; bottom: .65rem; max-width: 75%; font-size: .62rem; }
  .intro-section, .take-part { grid-template-columns: 1fr; row-gap: 1rem; }
  .intro-copy, .participant-list, .participation-note { grid-column: 1; }
  .section-label { flex-direction: row; align-items: center; }
  .participant-list { grid-template-columns: 1fr; }
  .participant-card { min-height: 0; }
  .participant-card h3 { margin-top: 1rem; }
  .route-stops { padding-left: 2.45rem; }
  .route-number { left: -3.45rem; }
  .sponsor-set { flex-basis: max(100vw, 540px); width: max(100vw, 540px); gap: .8rem; padding: 0 1rem; }
  .sponsor-logo { width: clamp(94px, 21vw, 128px); }
  .form-grid { grid-template-columns: 1fr; }
  .field-full { grid-column: auto; }
  .contact-hero { padding-top: 2.5rem; padding-bottom: 3.75rem; }
  .contact-direct { border-left: 0; border-top: 2px solid var(--river); padding: 1.2rem 0 0; }
  .site-footer { grid-template-columns: 1fr; gap: 1rem; }
  .site-footer .proposed-domain { grid-column: auto; }
}

@media (max-width: 380px) {
  .site-header nav { font-size: .67rem; }
  .nav-cta { padding: .5rem .55rem; }
  .brand-copy strong { font-size: .8rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .sponsor-track { animation: none; transform: none; }
  .sponsor-set[aria-hidden='true'] { display: none; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; scroll-behavior: auto !important; transition-duration: .01ms !important; }
}