/* GrandTour landing — deliberately spare: black, white, grays, one column;
   the phone frame on the right is the real web app in an iframe. */

* { box-sizing: border-box; }

:root {
  --ink: #111;
  --faint: #767676;
  --hairline: #ddd;
  --ghost: #f5f5f5;
}

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

body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  font-size: 1.0625rem;
  line-height: 1.6;
  color: var(--ink);
  background: #fff;
}

header, main, footer {
  max-width: 74rem;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* header */
header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding-top: 1.5rem;
  padding-bottom: 1.5rem;
}

.wordmark {
  font-weight: 600;
  letter-spacing: 0.01em;
}

nav {
  display: flex;
  align-items: baseline;
  gap: 1.25rem;
}

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

nav .app-link { font-weight: 600; }

.lang select {
  font: inherit;
  font-size: 0.9375rem;
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--hairline);
  border-radius: 0;
  padding: 0.15rem 0.4rem;
}

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

/* type */
h1 {
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  line-height: 1.15;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 1rem;
}

h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 0 0 0.75rem;
}

section { margin: 3.5rem 0; }

section#hero { margin-top: 2.5rem; }

p { margin: 0 0 1rem; }

ul { padding-left: 1.25rem; }

li { margin-bottom: 0.5rem; }

a { color: var(--ink); text-underline-offset: 3px; }

a:hover { text-decoration-thickness: 2px; }

/* The authored copy stays in its own readable column while the complete tour
   viewer occupies a phone-sized, sticky stage beside it. */
.landing-layout {
  display: grid;
  grid-template-columns: minmax(0, 44rem) minmax(20rem, 23.4375rem);
  align-items: start;
  justify-content: space-between;
  gap: clamp(3rem, 7vw, 7rem);
}

.copy-column { min-width: 0; }

.viewer-column {
  position: sticky;
  top: 1.25rem;
  margin: 2.5rem 0 3.5rem;
}

.phone-frame {
  width: 100%;
  aspect-ratio: 375 / 815;
  padding: 6px;
  overflow: hidden;
  border-radius: 3.25rem;
  background: #181818;
  box-shadow:
    0 2rem 4rem rgba(0, 0, 0, 0.18),
    0 0.25rem 0.9rem rgba(0, 0, 0, 0.12);
}

.phone-frame iframe {
  display: block;
  width: 100%;
  height: 100%;
  border: 0;
  border-radius: 2.875rem;
  background: #1a2128;
}



@media (max-width: 860px) {
  header, main, footer { max-width: 44rem; }
  .landing-layout { display: block; }
  .viewer-column {
    position: static;
    width: min(23.4375rem, 100%);
    margin: 3.5rem auto;
  }
}

/* footer */
footer {
  border-top: 1px solid var(--hairline);
  margin-top: 4rem;
  padding-top: 1.5rem;
  padding-bottom: 3rem;
  color: var(--faint);
  font-size: 0.9375rem;
}