/* ==========================================================================
   Sunscreen — marketing site
   One stylesheet, shared by index / the-math / privacy / support.
   Palette derives from the app icon: warm amber sun on near-black charcoal.
   ========================================================================== */

:root {
  /* surfaces */
  --bg:          #0F0F11;
  --surface:     #17171A;
  --surface-2:   #1E1E22;
  --line:        rgba(255, 255, 255, 0.09);
  --line-strong: rgba(255, 255, 255, 0.16);

  /* brand */
  --amber:        #E8AE30;
  --amber-bright: #F5D06B;
  --amber-dim:    #A8822E;

  /* data (sequential intensity — one hue, dim → bright) */
  --data-lo: #A8822E;
  --data-hi: #F0BE45;

  /* ink */
  --ink:   rgba(255, 255, 255, 0.93);
  --ink-2: rgba(255, 255, 255, 0.68);
  --ink-3: rgba(255, 255, 255, 0.45);

  /* type */
  --font-sans:  -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono:  ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  --font-serif: ui-serif, "New York", Georgia, "Times New Roman", serif;

  /* rhythm */
  --wrap: 62rem;
  --gap-section: clamp(5.5rem, 11vw, 10rem);
}

/* --------------------------------------------------------------- reset -- */

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink-2);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

a { color: var(--amber); text-decoration-color: rgba(232, 174, 48, 0.35); text-underline-offset: 3px; }
a:hover { color: var(--amber-bright); text-decoration-color: currentColor; }

h1, h2, h3 { color: var(--ink); line-height: 1.12; letter-spacing: -0.022em; margin: 0; font-weight: 600; }

:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
  border-radius: 4px;
}

/* -------------------------------------------------------------- layout -- */

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 5vw, 2.5rem);
}

.wrap--narrow { max-width: 40rem; }

section { padding-block: var(--gap-section); }

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--amber);
  color: #000;
  padding: 0.6rem 1rem;
  z-index: 100;
  border-radius: 0 0 8px 0;
  font-weight: 600;
}
.skip-link:focus { left: 0; }

/* ---------------------------------------------------------- typography -- */

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--amber);
  margin: 0 0 1.35rem;
}

.display {
  font-size: clamp(2.35rem, 6.4vw, 4rem);
  letter-spacing: -0.032em;
  font-weight: 600;
}

h2 { font-size: clamp(1.8rem, 3.9vw, 2.6rem); }
h3 { font-size: clamp(1.1rem, 2vw, 1.28rem); letter-spacing: -0.012em; }

.lede {
  font-size: clamp(1.06rem, 1.9vw, 1.28rem);
  line-height: 1.6;
  color: var(--ink-2);
  max-width: 34em;
  margin: 1.6rem 0 0;
}

p { margin: 1.15rem 0 0; max-width: 38em; }

strong { color: var(--ink); font-weight: 600; }

.mono { font-family: var(--font-mono); font-size: 0.94em; color: var(--ink); }

.muted { color: var(--ink-3); }

.small { font-size: 0.9rem; line-height: 1.6; }

/* ---------------------------------------------------------------- nav --- */

.nav {
  position: relative;
  z-index: 3;
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding-block: 1.6rem;
}

.nav__mark { width: 30px; height: 30px; border-radius: 8px; }

.nav__name {
  color: var(--ink);
  font-weight: 600;
  letter-spacing: -0.01em;
  text-decoration: none;
  font-size: 1.02rem;
}

.nav__links {
  margin-left: auto;
  display: flex;
  gap: clamp(1rem, 3vw, 1.9rem);
  font-size: 0.94rem;
}

.nav__links a { color: var(--ink-3); text-decoration: none; }
.nav__links a:hover { color: var(--ink); }

/* --------------------------------------------------------------- hero --- */

.hero {
  position: relative;
  padding-block: clamp(3rem, 7vw, 5.5rem) var(--gap-section);
}

/* the single soft glow on the page */
.hero::before {
  content: "";
  position: absolute;
  top: -14rem;
  left: 50%;
  width: min(78rem, 155vw);
  aspect-ratio: 1;
  transform: translateX(-50%);
  background: radial-gradient(circle, rgba(232, 174, 48, 0.13) 0%, rgba(232, 174, 48, 0.045) 34%, transparent 62%);
  pointer-events: none;
  z-index: 0;
}

.hero > * { position: relative; z-index: 1; }

.hero__grid {
  display: grid;
  gap: clamp(3rem, 7vw, 4.5rem);
  align-items: center;
}

@media (min-width: 62rem) {
  .hero__grid { grid-template-columns: 1.08fr 0.92fr; }
}

.hero__icon {
  width: 78px;
  height: 78px;
  border-radius: 20px;
  margin-bottom: 1.9rem;
  box-shadow: 0 10px 44px rgba(232, 174, 48, 0.2);
}

/* ---------------------------------------------------------------- cta --- */

.cta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem 1.5rem;
  margin-top: 2.4rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.85rem 1.45rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.98rem;
  text-decoration: none;
  transition: transform 0.16s ease, box-shadow 0.16s ease, background 0.16s ease;
}

.btn--primary {
  background: linear-gradient(180deg, var(--amber-bright), var(--amber));
  color: #17130A;
  box-shadow: 0 6px 26px rgba(232, 174, 48, 0.26);
}
.btn--primary:hover {
  color: #17130A;
  transform: translateY(-1px);
  box-shadow: 0 9px 32px rgba(232, 174, 48, 0.36);
}

.btn--ghost {
  color: var(--ink-2);
  border: 1px solid var(--line-strong);
}
.btn--ghost:hover { color: var(--ink); background: var(--surface); }

.btn__sub {
  display: block;
  font-size: 0.68rem;
  font-weight: 500;
  opacity: 0.72;
  letter-spacing: 0.02em;
  line-height: 1.2;
}

.cta-note { font-size: 0.86rem; color: var(--ink-3); margin: 0; }

/* -------------------------------------------------------------- watch --- */

.watch {
  --watch-w: 15.5rem;
  width: var(--watch-w);
  aspect-ratio: 422 / 514;
  border-radius: 15.5%;
  padding: 3px;
  background: linear-gradient(160deg, #3A3A3E, #131315 42%, #0A0A0B);
  box-shadow:
    0 0 0 1px rgba(255, 255, 255, 0.05),
    0 26px 60px -18px rgba(0, 0, 0, 0.9);
  flex: none;
}

.watch img,
.watch .watch__ph {
  width: 100%;
  height: 100%;
  border-radius: 14.4%;
  object-fit: cover;
  background: #000;
}

/* placeholder, used if an image is ever missing */
.watch__ph {
  display: grid;
  place-content: center;
  color: var(--ink-3);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-align: center;
}

.watch--hero { --watch-w: min(17.5rem, 74vw); margin-inline: auto; }

.watch-row {
  display: flex;
  gap: clamp(1.25rem, 3.5vw, 2.25rem);
  overflow-x: auto;
  padding-block: 0.5rem 1.25rem;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
}
.watch-row > * { scroll-snap-align: center; }
.watch-row .watch { --watch-w: 13.5rem; }

/* ------------------------------------------------------------ premise --- */

.premise {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.014), transparent);
}

.premise__quote {
  font-family: var(--font-serif);
  font-size: clamp(1.55rem, 3.9vw, 2.5rem);
  line-height: 1.32;
  letter-spacing: -0.015em;
  color: var(--ink);
  margin: 0;
  max-width: 20em;
}

.premise__quote em { color: var(--amber); font-style: italic; }

/* -------------------------------------------------------------- ideas --- */

.idea { margin-top: var(--gap-section); }
.idea:first-of-type { margin-top: 3.5rem; }

.idea__num {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--amber);
  display: block;
  margin-bottom: 0.9rem;
}

.idea h3 {
  font-size: clamp(1.45rem, 3.2vw, 2.05rem);
  letter-spacing: -0.024em;
  max-width: 18em;
}

/* ------------------------------------------------------------- figure --- */

.figure {
  margin: 2.75rem 0 0;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  overflow: hidden;
}

.figure__body { overflow-x: auto; padding: clamp(1rem, 3vw, 1.75rem); }

.figure svg { display: block; width: 100%; height: auto; min-width: 30rem; }

.figure figcaption {
  border-top: 1px solid var(--line);
  padding: 0.95rem clamp(1rem, 3vw, 1.75rem);
  font-size: 0.87rem;
  line-height: 1.55;
  color: var(--ink-3);
  background: rgba(0, 0, 0, 0.22);
  max-width: none;
}

.figure figcaption strong { color: var(--ink-2); font-weight: 600; }

/* svg helpers */
.svg-label   { font-family: var(--font-sans); font-size: 12px; fill: rgba(255,255,255,0.45); }
.svg-value   { font-family: var(--font-mono); font-size: 21px; font-weight: 600; fill: #F5D06B; }
.svg-title   { font-family: var(--font-sans); font-size: 13px; font-weight: 600; fill: rgba(255,255,255,0.93); }
.svg-note    { font-family: var(--font-sans); font-size: 11.5px; fill: rgba(255,255,255,0.45); }
.svg-axis    { stroke: rgba(255,255,255,0.16); stroke-width: 1; }
.svg-grid    { stroke: rgba(255,255,255,0.07); stroke-width: 1; }

/* --------------------------------------------------------------- grid --- */

.cards {
  display: grid;
  gap: 1px;
  margin-top: 3.25rem;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 16px;
  overflow: hidden;
}

@media (min-width: 46rem) { .cards { grid-template-columns: 1fr 1fr; } }

.card {
  background: var(--surface);
  padding: clamp(1.5rem, 3.4vw, 2.1rem);
}

.card h3 { margin-bottom: 0.55rem; }
.card p { margin: 0; font-size: 0.96rem; color: var(--ink-2); }

.card__k {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--amber-dim);
  display: block;
  margin-bottom: 0.9rem;
}

/* --------------------------------------------------------------- step --- */

.steps {
  display: grid;
  gap: clamp(2.5rem, 5vw, 3.5rem);
  margin-top: 3.5rem;
}

@media (min-width: 52rem) { .steps { grid-template-columns: repeat(3, 1fr); } }

.step { display: flex; flex-direction: column; align-items: flex-start; gap: 1.5rem; }
.step .watch { --watch-w: 100%; max-width: 14rem; align-self: center; }
.step h3 { margin-bottom: 0.5rem; }
.step p { margin: 0; font-size: 0.96rem; }
.step__n {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--amber);
}

/* ------------------------------------------------------------- inline --- */

.callout {
  margin-top: 2.5rem;
  padding: 1.4rem 1.6rem;
  border-left: 2px solid var(--amber);
  background: linear-gradient(90deg, rgba(232, 174, 48, 0.07), transparent 70%);
  border-radius: 0 10px 10px 0;
}
.callout p { margin: 0; }

.disclaimer {
  margin-top: 3rem;
  font-size: 0.84rem;
  color: var(--ink-3);
  max-width: 44em;
}

.rule { border: 0; border-top: 1px solid var(--line); margin: 0; }

/* --------------------------------------------------------------- prose - */

.prose h2 { margin-top: 3.25rem; font-size: clamp(1.3rem, 2.6vw, 1.6rem); }
.prose h2:first-of-type { margin-top: 2.5rem; }
.prose ul { margin: 1.15rem 0 0; padding-left: 1.15rem; max-width: 38em; }
.prose li { margin-bottom: 0.6rem; }
.prose li::marker { color: var(--amber-dim); }

.refs { margin-top: 1.5rem; padding-left: 0; list-style: none; }
.refs li {
  font-size: 0.9rem;
  color: var(--ink-3);
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--line);
  max-width: 44em;
}

/* ------------------------------------------------------------- footer --- */

.footer {
  border-top: 1px solid var(--line);
  padding-block: clamp(3.5rem, 7vw, 5rem) 3rem;
}

.footer__cta { text-align: center; padding-bottom: clamp(3rem, 6vw, 4.5rem); }
.footer__cta h2 { max-width: 16em; margin-inline: auto; }
.footer__cta .cta-row { justify-content: center; }
.footer__cta .lede { margin-inline: auto; }

.footer__bar {
  border-top: 1px solid var(--line);
  padding-top: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem 1.75rem;
  align-items: center;
  font-size: 0.88rem;
  color: var(--ink-3);
}

.footer__bar a { color: var(--ink-3); text-decoration: none; }
.footer__bar a:hover { color: var(--ink); }
.footer__bar .spacer { margin-left: auto; }

/* ------------------------------------------------------------- motion --- */

.reveal { opacity: 0; transform: translateY(14px); }

.reveal.is-in {
  opacity: 1;
  transform: none;
  transition: opacity 0.5s ease, transform 0.5s cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* Content must never depend on JS: if JS is off, nothing is hidden. */
.no-js .reveal { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1 !important; transform: none !important; transition: none !important; }
  * { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}

/* ------------------------------------------------------- refinements --- */

.display, h2, h3, .premise__quote { text-wrap: balance; }
.lede { text-wrap: pretty; }

/* Two-panel figures: side by side on wide screens, stacked on narrow ones,
   so the comparison survives instead of turning into a sideways scroll. */
.figure__panels { display: grid; }
.figure__panels > div { padding: clamp(0.9rem, 2.4vw, 1.5rem); min-width: 0; }
.figure__panels svg { min-width: 0; }

@media (min-width: 44rem) {
  .figure__panels { grid-template-columns: 1fr 1fr; }
  .figure__panels > div + div { border-left: 1px solid var(--line); }
}
@media (max-width: 43.999rem) {
  .figure__panels > div + div { border-top: 1px solid var(--line); }
}

/* In the narrow prose column, let figures break out to a readable width.
   Capped so it never exceeds the viewport (no horizontal page scroll). */
.wrap--narrow .figure {
  width: min(52rem, calc(100vw - 2.5rem));
  position: relative;
  left: 50%;
  transform: translateX(-50%);
}

/* ------------------------------------------------- inline citations ----- */

.ref {
  font-family: var(--font-mono);
  font-size: 0.62em;
  vertical-align: super;
  line-height: 0;
  margin-left: 0.1em;
  padding: 0 0.1em;
  color: var(--amber);
  text-decoration: none;
}
.ref:hover, .ref:focus-visible { text-decoration: underline; }

ol.refs { counter-reset: ref; }

ol.refs li {
  counter-increment: ref;
  position: relative;
  padding: 0.75rem 0 0.75rem 2rem;
  scroll-margin-top: 2rem;
}

ol.refs li::before {
  content: counter(ref);
  position: absolute;
  left: 0;
  top: 0.9rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--amber);
}

ol.refs li:target { background: rgba(232, 174, 48, 0.07); }

.refs cite { font-style: italic; color: var(--ink-2); }
.refs a { color: var(--ink-3); text-decoration-color: rgba(255, 255, 255, 0.22); }
.refs a:hover { color: var(--amber); }

/* the hero shot is a Series 11 export (416×496); the step shots are SE (368×448) */
.watch--hero { aspect-ratio: 416 / 496; }

/* two citations on one claim read as "2,3" */
.ref + .ref::before { content: ","; margin-right: 0.08em; }

/* ------------------------------------------------------ hero carousel --- */
/* One bezel; the screen inside it slides. Without JavaScript the track sits
   at the first shot and the controls are hidden, so it degrades to a still. */

.hero-carousel { width: min(17.5rem, 74vw); margin-inline: auto; user-select: none; -webkit-user-select: none; }
.hero-carousel .watch { --watch-w: 100%; }

.carousel__frame {
  width: 100%; height: 100%;
  border-radius: 14.4%;
  overflow: hidden;
  background: #000;
  cursor: grab;
  touch-action: pan-y;
}
.carousel__frame:active { cursor: grabbing; }

.carousel__track { display: flex; height: 100%; will-change: transform; }
.carousel__track.is-animating { transition: transform 0.55s cubic-bezier(0.22, 0.61, 0.36, 1); }
.carousel__track img { flex: none; width: 100%; height: 100%; object-fit: cover; border-radius: 0; -webkit-user-drag: none; }

.carousel__controls { display: flex; align-items: center; justify-content: center; gap: 1rem; margin-top: 1.25rem; }
.no-js .carousel__controls { display: none; }

.carousel__arrow {
  display: grid; place-items: center;
  width: 2.25rem; height: 2.25rem;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  background: none;
  color: var(--ink-2);
  cursor: pointer;
  transition: background 0.16s ease, color 0.16s ease;
}
.carousel__arrow:hover { background: var(--surface); color: var(--ink); }

.carousel__dots { display: flex; align-items: center; gap: 0.5rem; }
.carousel__dot {
  width: 0.375rem; height: 0.375rem;
  border-radius: 999px; border: 0; padding: 0;
  background: rgba(255, 255, 255, 0.25);
  cursor: pointer;
  transition: width 0.2s ease, background 0.2s ease;
}
.carousel__dot:hover { background: rgba(255, 255, 255, 0.45); }
.carousel__dot[aria-selected="true"] { width: 1.25rem; background: var(--amber); }

.carousel__note { text-align: center; margin-top: 1rem; }

@media (prefers-reduced-motion: reduce) { .carousel__track.is-animating { transition: none; } }

/* ------------------------------------------------------- complications --- */

.complications { display: flex; justify-content: center; gap: clamp(1.25rem, 3.5vw, 2.25rem); margin-top: 3.25rem; }
.complications .watch { --watch-w: min(12rem, 40vw); }
.complications__note { text-align: center; margin-top: 1.25rem; max-width: none; }

/* a single watch shot in the prose column, with a caption */
.watch-figure { margin: 2.75rem auto 0; width: min(22rem, 80vw); text-align: center; }
.watch-figure .watch { --watch-w: min(13rem, 60vw); margin-inline: auto; }
.watch-figure figcaption { margin-top: 1rem; font-size: 0.87rem; line-height: 1.55; color: var(--ink-3); }