/* Hydrogen H2O Life — "The Drop Test" */

:root {
  --bench: #f2f6f9;
  --glass: #ffffff;
  --ink: #0a2b52;
  --navy: #0e4c8c;
  --cyan: #1ba6e4;
  --link: #0a6b9c;
  --muted: #3f5d7d;
  --line: #d2dde8;
  --line-strong: #b4c6d8;
  --tube-glass: rgba(14, 76, 140, 0.16);
  --shadow: 0 1px 2px rgba(10, 43, 82, 0.06), 0 8px 24px -12px rgba(10, 43, 82, 0.18);

  --ph115: #5a2d8c;
  --ph95: #3f46a8;
  --ph90: #2d6cc0;
  --ph85: #17899f;
  --ph70: #237a42;
  --ph60: #d9b41c;
  --ph25: #c0352a;
  --field: #0e4c8c;
  --error: #9b1c4d;

  --display: "Gabarito", ui-rounded, system-ui, sans-serif;
  --text: "Atkinson Hyperlegible Next", "Atkinson Hyperlegible", system-ui, sans-serif;

  --gutter: clamp(16px, 4vw, 48px);
  --max: 1240px;
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bench: #08182b;
    --glass: #0d2340;
    --ink: #e4eef8;
    --navy: #9cc9f2;
    --cyan: #4fc2f2;
    --link: #7fd0f5;
    --muted: #a6bdd4;
    --line: #1c3656;
    --line-strong: #2b4a70;
    --tube-glass: rgba(156, 201, 242, 0.22);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 10px 28px -12px rgba(0, 0, 0, 0.6);
    --ph60: #e2c03a;
    --field: #0c3563;
    --error: #ff94b8;
    color-scheme: dark;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: 96px; }
html { scrollbar-color: var(--line-strong) var(--bench); }
body {
  margin: 0;
  caret-color: var(--cyan);
  background: var(--bench);
  color: var(--ink);
  font-family: var(--text);
  font-size: 1.125rem;
  line-height: 1.6;
  font-variant-numeric: lining-nums;
  -webkit-font-smoothing: antialiased;
}
::selection { background: var(--navy); color: #fff; }
img, svg { display: block; max-width: 100%; }
a { color: var(--link); text-underline-offset: 0.2em; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--cyan); outline-offset: 3px; border-radius: 4px; }
h1, h2, h3 { font-family: var(--display); line-height: 1.08; letter-spacing: -0.02em; margin: 0; text-wrap: balance; color: var(--ink); }
p { margin: 0 0 1em; text-wrap: pretty; }
.wrap { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 var(--gutter); }
.skip { position: absolute; left: -999px; top: 8px; background: var(--ink); color: var(--bench); padding: 8px 14px; border-radius: 8px; z-index: 50; }
.skip:focus { left: 8px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.tabular { font-variant-numeric: tabular-nums; }

/* ---------- header ---------- */
.site-head {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bench) 92%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.site-head .wrap { display: flex; align-items: center; gap: 24px; min-height: 76px; }
.brand { display: flex; align-items: center; flex: none; }
.brand img { height: 62px; width: auto; }
:root[data-theme="dark"] .brand img, .brand-dark .brand img { filter: none; }
.nav { margin-left: auto; display: flex; align-items: center; gap: 4px; }
.nav a {
  font-family: var(--display); font-weight: 600; font-size: 1rem;
  color: var(--ink); text-decoration: none;
  padding: 10px 12px; border-radius: 10px;
}
.nav a:hover { background: color-mix(in srgb, var(--cyan) 12%, transparent); }
.nav a[aria-current="page"] { color: var(--navy); box-shadow: inset 0 -3px 0 var(--cyan); border-radius: 0; }
.nav .btn { margin-left: 8px; }
.menu-toggle { display: none; margin-left: auto; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--display); font-weight: 700; font-size: 1.0625rem;
  padding: 14px 22px; border-radius: 999px; text-decoration: none;
  border: 2px solid transparent; cursor: pointer;
  transition: transform 200ms var(--ease-out), background-color 200ms, box-shadow 200ms;
}
.btn svg { width: 20px; height: 20px; flex: none; }
.btn-primary { background: var(--navy); color: #fff; box-shadow: 0 6px 18px -8px rgba(14, 76, 140, 0.7); }
.btn-primary:hover { background: color-mix(in srgb, var(--navy) 86%, #000); transform: translateY(-1px); }
.btn-ghost { color: var(--ink); border-color: var(--line-strong); background: transparent; }
.btn-ghost:hover { border-color: var(--navy); }
.nav .btn { padding: 10px 18px; font-size: 1rem; color: #fff; }
.nav .btn:hover { background: color-mix(in srgb, var(--navy) 86%, #000); }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .btn-primary, :root:not([data-theme="light"]) .nav .btn { background: var(--cyan); color: #04213d; box-shadow: 0 6px 18px -10px rgba(0, 0, 0, 0.6); }
  :root:not([data-theme="light"]) .brand img, :root:not([data-theme="light"]) .foot-grid img { background: #fff; border-radius: 12px; padding: 4px 8px; }
  :root:not([data-theme="light"]) .readout .ph-big { color: color-mix(in srgb, var(--c) 45%, #fff); }
  :root:not([data-theme="light"]) .close .form { color: var(--ink); }
  :root:not([data-theme="light"]) .tube .glass { background-color: rgba(255, 255, 255, 0.07); }
  :root:not([data-theme="light"]) .tube .liquid { background: color-mix(in srgb, var(--c) 20%, transparent); border-top-color: color-mix(in srgb, var(--c) 60%, #fff); }
  :root:not([data-theme="light"]) .tube .liquid::after { background: color-mix(in srgb, var(--c) 72%, #fff); }
}

/* ---------- the rack ---------- */
.rack {
  --tube-w: clamp(34px, 3.6vw, 50px);
  --tube-h: clamp(220px, 34vw, 400px);
  position: relative;
  display: grid; grid-template-columns: repeat(7, var(--tube-w));
  justify-content: space-between;
  padding: clamp(20px, 3vw, 34px) clamp(14px, 3vw, 34px) 0;
  background: var(--glass);
  border-radius: 16px 16px 6px 6px;
  box-shadow: var(--shadow);
}
.rack::after { /* the rack's front rail */
  content: ""; position: absolute; left: 0; right: 0; bottom: 64px; height: 18px;
  background: var(--navy); opacity: 0.92; border-radius: 3px;
}
.tube {
  --c: var(--ph95);
  position: relative; display: grid; justify-items: center; gap: 0;
  background: none; border: 0; padding: 0; cursor: pointer; color: var(--ink);
  font: inherit;
}
.tube .cap {
  width: calc(var(--tube-w) * 1.12); height: 20px; border-radius: 6px 6px 3px 3px;
  background: color-mix(in srgb, var(--navy) 85%, var(--bench));
}
.tube .glass {
  position: relative; width: var(--tube-w); height: var(--tube-h);
  border: 2px solid var(--tube-glass); border-top: 0;
  border-radius: 0 0 calc(var(--tube-w) / 2) calc(var(--tube-w) / 2);
  background: linear-gradient(90deg, rgba(255,255,255,0.0) 10%, rgba(255,255,255,0.55) 22%, rgba(255,255,255,0) 34%);
  overflow: hidden;
}
.tube .liquid {
  position: absolute; left: 0; right: 0; bottom: 0; height: 72%;
  background: color-mix(in srgb, var(--c) 13%, transparent);
  border-top: 2px solid color-mix(in srgb, var(--c) 30%, transparent);
}
.tube .liquid::after {
  content: ""; position: absolute; inset: 0;
  background: var(--c);
  clip-path: circle(0% at 50% 0%);
  transition: clip-path 1100ms var(--ease-out);
}
.tube[aria-selected="true"] .liquid::after { clip-path: circle(160% at 50% 0%); transition-delay: 380ms; }
.tube .shine {
  position: absolute; top: 0; bottom: 14px; left: 18%; width: 12%;
  background: rgba(255,255,255,0.5); border-radius: 99px; z-index: 2; pointer-events: none;
}
.tube .drop {
  position: absolute; left: 50%; top: -36px; width: 12px; height: 16px; margin-left: -6px;
  background: var(--c); border-radius: 50% 50% 50% 50% / 62% 62% 38% 38%;
  opacity: 0; z-index: 3; pointer-events: none;
}
.tube.dripping .drop { animation: drip 520ms cubic-bezier(0.55, 0, 1, 0.45) forwards; }
@keyframes drip {
  0% { opacity: 0; transform: translateY(0) scale(0.6); }
  15% { opacity: 1; transform: translateY(0) scale(1); }
  100% { opacity: 1; transform: translateY(calc(var(--tube-h) * 0.3 + 40px)) scaleY(1.2); }
}
.tube .ph {
  height: 64px; display: grid; place-items: center; position: relative; z-index: 1;
  font-family: var(--display); font-weight: 700; font-size: clamp(0.95rem, 1.4vw, 1.2rem);
  color: var(--muted); font-variant-numeric: tabular-nums; letter-spacing: -0.01em;
  transition: color 400ms;
}
.tube[aria-selected="true"] .ph { color: var(--ink); }
.tube[aria-selected="true"] .ph::after { content: ""; position: absolute; bottom: 10px; left: 50%; width: 18px; height: 3px; margin-left: -9px; border-radius: 2px; background: var(--c); }
.tube:hover .liquid { background: color-mix(in srgb, var(--c) 24%, transparent); }
.tube:focus-visible { outline-offset: 6px; }
.readout {
  --c: var(--ph95);
  background: var(--glass); border-radius: 6px 6px 16px 16px; box-shadow: var(--shadow);
  padding: 22px clamp(18px, 3vw, 30px) 26px;
  box-shadow: inset 0 8px 0 var(--c), var(--shadow);
  padding-top: 30px;
  transition: box-shadow 600ms var(--ease-out);
  min-height: 236px;
}
.readout-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.readout h2 { font-size: clamp(1.5rem, 2.4vw, 2rem); }
.readout .ph-big { font-family: var(--display); font-weight: 800; font-size: 1.25rem; color: var(--c); font-variant-numeric: tabular-nums; }
.readout .verdict { margin: 6px 0 14px; color: var(--muted); }
.readout ul { margin: 0 0 16px; padding: 0; list-style: none; display: grid; gap: 8px; }
.readout li { display: grid; grid-template-columns: 14px 1fr; gap: 10px; align-items: baseline; }
.readout li::before { content: ""; width: 10px; height: 10px; border-radius: 50%; background: var(--c); transform: translateY(1px); }
.readout a.more { font-family: var(--display); font-weight: 700; text-decoration: none; display: inline-flex; gap: 8px; align-items: center; }
.readout a.more svg { width: 18px; height: 18px; transition: transform 200ms var(--ease-out); }
.readout a.more:hover svg { transform: translateX(3px); }
.readout-body { animation: fadeUp 500ms var(--ease-out); }
@keyframes fadeUp { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* ---------- hero ---------- */
.hero { padding: clamp(36px, 6vw, 80px) 0 clamp(56px, 8vw, 104px); }
.hero .wrap { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr); gap: clamp(32px, 5vw, 72px); align-items: start; }
.hero h1 { font-size: clamp(2.5rem, 4.6vw, 4.25rem); font-weight: 800; letter-spacing: -0.03em; margin-bottom: 24px; }
.hero h1 em { font-style: normal; color: var(--navy); }
.hero .lede { font-size: clamp(1.125rem, 1.6vw, 1.3rem); color: var(--muted); max-width: 34ch; margin-bottom: 30px; }
.hero .actions { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 28px; }
.hero .phone-line { color: var(--muted); font-size: 1rem; }
.hero .phone-line a { font-weight: 700; font-variant-numeric: tabular-nums; }
.hero-copy { padding-top: clamp(0px, 3vw, 40px); }
.lab { display: grid; gap: 10px; }
.lab-hint { font-size: 0.9375rem; color: var(--muted); margin: 4px 2px 0; }

/* ---------- sections ---------- */
.section { padding: clamp(64px, 9vw, 128px) 0; }
.section + .section { border-top: 1px solid var(--line); }
.section h2 { font-size: clamp(2rem, 4vw, 3.4rem); font-weight: 800; margin-bottom: 20px; }
.section .intro { font-size: 1.1875rem; color: var(--muted); max-width: 60ch; }

/* equation */
.equation { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr); gap: clamp(32px, 6vw, 96px); align-items: center; }
.eq-figure { display: flex; align-items: center; justify-content: center; gap: clamp(10px, 2vw, 28px); flex-wrap: wrap; }
.eq-figure figure { margin: 0; display: grid; justify-items: center; gap: 10px; }
.eq-figure svg { height: clamp(90px, 13vw, 150px); width: auto; }
.eq-figure figcaption { font-family: var(--display); font-weight: 800; font-size: clamp(1.5rem, 3vw, 2.4rem); letter-spacing: -0.02em; }
.eq-figure figcaption small { display: block; font-family: var(--text); font-weight: 400; font-size: 0.9375rem; color: var(--muted); letter-spacing: 0; text-align: center; }
.eq-op { font-family: var(--display); font-weight: 800; font-size: clamp(2rem, 4vw, 3.4rem); color: var(--cyan); padding-bottom: 40px; }
.eq-result { font-family: var(--display); font-weight: 800; font-size: clamp(1.4rem, 2.4vw, 2rem); color: var(--navy); margin: 28px 0 0; text-align: center; }
.copy-col p { max-width: 58ch; }
.copy-col strong { color: var(--navy); }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .copy-col strong { color: var(--cyan); } }

/* timeline frames */
.frames { list-style: none; margin: 40px 0 0; padding: 0; display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 0; position: relative; }
.frames li { position: relative; padding: 28px 18px 0 0; border-top: 3px solid var(--line-strong); }
.frames li::before { content: ""; position: absolute; top: -9px; left: 0; width: 15px; height: 15px; border-radius: 50%; background: var(--bench); border: 3px solid var(--line-strong); }
.frames li.after { border-top-color: var(--cyan); }
.frames li.after::before { background: var(--cyan); border-color: var(--cyan); }
.frames li.threshold::after {
  content: ""; position: absolute; top: -34px; left: -2px; width: 14px; height: 18px;
  background: var(--cyan); border-radius: 50% 50% 50% 50% / 62% 62% 38% 38%;
  transform: rotate(180deg);
}
.frames time { display: block; font-family: var(--display); font-weight: 800; font-size: 1.25rem; margin-bottom: 8px; font-variant-numeric: tabular-nums; }
.frames p { font-size: 1rem; color: var(--muted); margin: 0; }
.frames li.after p { color: var(--ink); }

.pull { margin: clamp(48px, 7vw, 88px) 0 0; display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 32px; align-items: end; }
.pull blockquote { margin: 0; font-family: var(--display); font-weight: 700; font-size: clamp(1.75rem, 3.6vw, 3rem); line-height: 1.12; letter-spacing: -0.02em; max-width: 24ch; color: var(--navy); }
.pull blockquote cite { display: block; margin-top: 16px; font-family: var(--text); font-style: normal; font-weight: 400; font-size: 1rem; color: var(--muted); letter-spacing: 0; }

/* research index */
.research-head { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 24px; align-items: end; margin-bottom: 36px; }
.topic-index { columns: 3 260px; column-gap: 40px; margin: 0; padding: 0; list-style: none; }
.topic-index li { break-inside: avoid; border-bottom: 1px solid var(--line); }
.topic-index a { display: flex; justify-content: space-between; gap: 16px; padding: 12px 2px; text-decoration: none; color: var(--ink); }
.topic-index a:hover { color: var(--link); }
.topic-index .n { color: var(--muted); font-variant-numeric: tabular-nums; font-size: 0.9375rem; }

/* close / contact */
.close { background: var(--field); color: #fff; }
.close h2, .close .intro { color: #fff; }
.close .intro { opacity: 0.88; }
.close-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: clamp(32px, 6vw, 88px); align-items: start; }
.reach { list-style: none; margin: 32px 0 0; padding: 0; display: grid; gap: 4px; }
.reach a { display: flex; align-items: center; gap: 14px; color: #fff; text-decoration: none; font-family: var(--display); font-weight: 700; font-size: 1.25rem; padding: 12px 0; }
.reach a span small { display: block; font-family: var(--text); font-weight: 400; font-size: 0.9375rem; opacity: 0.8; }
.reach svg { width: 26px; height: 26px; flex: none; color: var(--cyan); }
.reach a:hover span { text-decoration: underline; text-underline-offset: 0.2em; }
.form { background: var(--glass); color: var(--ink); border-radius: 16px; padding: clamp(22px, 3vw, 34px); box-shadow: 0 20px 40px -20px rgba(0,0,0,0.45); }
.form h3 { font-size: 1.5rem; margin-bottom: 18px; }
.field { display: grid; gap: 6px; margin-bottom: 16px; }
.field label { font-weight: 700; font-size: 1rem; }
.field input, .field textarea, .field select {
  font: inherit; font-size: 1.0625rem; color: var(--ink);
  background: var(--bench); border: 2px solid var(--line); border-radius: 10px; padding: 12px 14px; width: 100%;
}
.field textarea { min-height: 120px; resize: vertical; }
.field input:focus, .field textarea:focus, .field select:focus { outline: none; border-color: var(--cyan); background: var(--glass); }
.field .err { color: var(--error); font-size: 0.9375rem; display: none; }
.field.invalid .err { display: block; }
.field.invalid input { border-color: var(--error); }
.form .note { font-size: 0.9375rem; color: var(--muted); margin: 12px 0 0; }
.choice { display: flex; flex-wrap: wrap; gap: 8px; border: 0; padding: 0; margin: 0 0 16px; }
.choice legend { font-weight: 700; font-size: 1rem; margin-bottom: 6px; }
.choice label { display: inline-flex; align-items: center; gap: 8px; border: 2px solid var(--line); border-radius: 999px; padding: 8px 14px; cursor: pointer; font-size: 1rem; }
.choice input { accent-color: var(--navy); }
.choice label:has(input:checked) { border-color: var(--navy); background: color-mix(in srgb, var(--cyan) 10%, transparent); }

/* ---------- page heads (inner pages) ---------- */
.page-head { padding: clamp(48px, 7vw, 96px) 0 clamp(32px, 4vw, 56px); }
.page-head h1 { font-size: clamp(2.4rem, 5vw, 4.4rem); font-weight: 800; letter-spacing: -0.03em; margin-bottom: 18px; max-width: 18ch; }
.page-head .intro { font-size: clamp(1.125rem, 1.5vw, 1.3rem); color: var(--muted); max-width: 60ch; }

/* ladder strip: the pH card */
.ladder { display: grid; grid-template-columns: repeat(7, 1fr); height: 10px; }
.ladder span:nth-child(1) { background: var(--ph115); }
.ladder span:nth-child(2) { background: var(--ph95); }
.ladder span:nth-child(3) { background: var(--ph90); }
.ladder span:nth-child(4) { background: var(--ph85); }
.ladder span:nth-child(5) { background: var(--ph70); }
.ladder span:nth-child(6) { background: var(--ph60); }
.ladder span:nth-child(7) { background: var(--ph25); }

/* waters page */
.mini-rack { position: sticky; top: 76px; z-index: 10; background: color-mix(in srgb, var(--bench) 94%, transparent); backdrop-filter: blur(10px); border-bottom: 1px solid var(--line); }
.mini-rack ul { list-style: none; margin: 0 auto; padding: 10px var(--gutter); max-width: var(--max); display: flex; flex-wrap: wrap; gap: 8px; }
@media (max-width: 860px) { .mini-rack ul { flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; } }
.mini-rack a {
  --c: var(--ph95);
  display: inline-flex; align-items: center; gap: 10px; white-space: nowrap;
  padding: 8px 14px 8px 8px; border-radius: 999px; border: 2px solid var(--line);
  color: var(--ink); text-decoration: none; font-family: var(--display); font-weight: 700; font-size: 0.9375rem; background: var(--glass);
}
.mini-rack a i { width: 22px; height: 22px; border-radius: 50%; background: var(--c); display: grid; place-items: center; }
.mini-rack a:hover, .mini-rack a.active { border-color: var(--c); }
.group { padding: 0 0 clamp(48px, 6vw, 80px); }
.group-band { --c: var(--ph95); background: var(--c); color: #fff; padding: clamp(36px, 5vw, 64px) 0 clamp(28px, 4vw, 44px); margin-bottom: clamp(28px, 4vw, 48px); }
.group-band.light-ink { color: #1b1a05; }
.group-band h2 { color: inherit; font-size: clamp(2rem, 4.4vw, 3.6rem); font-weight: 800; }
.band-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.group-band .ph-tag { font-family: var(--display); font-weight: 800; font-size: clamp(1.4rem, 2.6vw, 2.2rem); font-variant-numeric: tabular-nums; }
.group-band p { max-width: 62ch; margin: 14px 0 0; font-size: 1.125rem; }
.uses { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 clamp(28px, 4vw, 56px); }
.uses li { display: grid; grid-template-columns: 3ch 1fr; gap: 14px; padding: 18px 0; border-bottom: 1px solid var(--line); break-inside: avoid; }
.uses .num { font-family: var(--display); font-weight: 800; color: var(--muted); font-variant-numeric: tabular-nums; text-align: right; }
.uses h3 { font-size: 1.1875rem; font-weight: 700; margin-bottom: 4px; letter-spacing: -0.01em; }
.uses p { margin: 0; font-size: 1.0625rem; color: color-mix(in srgb, var(--ink) 86%, var(--bench)); }
.steps { margin: 0; padding-left: 1.4em; }
.steps li { margin-bottom: 6px; }
.prose { max-width: 68ch; }
.prose h2 { font-size: clamp(1.6rem, 2.8vw, 2.2rem); margin: 48px 0 14px; }
.prose h3 { font-size: 1.3rem; margin: 28px 0 10px; }
.two-col { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: clamp(28px, 5vw, 72px); }

/* science page */
.sci-tools { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; margin-top: 28px; }
.search { position: relative; flex: 1 1 320px; max-width: 520px; }
.search svg { position: absolute; left: 14px; top: 50%; translate: 0 -50%; width: 20px; height: 20px; color: var(--muted); }
.search input { width: 100%; font: inherit; color: var(--ink); background: var(--glass); border: 2px solid var(--line); border-radius: 999px; padding: 12px 18px 12px 44px; }
.search input:focus { outline: none; border-color: var(--cyan); }
.sci-count { color: var(--muted); font-size: 1rem; }
.sci-list { list-style: none; margin: 0; padding: 0; }
.sci-topic { display: grid; grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.6fr); gap: 24px; padding: 24px 0; border-bottom: 1px solid var(--line); }
.sci-topic h2 { font-size: 1.375rem; font-weight: 700; letter-spacing: -0.01em; }
.sci-topic h2 small { display: block; font-family: var(--text); font-weight: 400; font-size: 0.9375rem; color: var(--muted); margin-top: 4px; }
.sources { list-style: none; margin: 0; padding: 0; display: grid; gap: 14px; }
.sources a { color: var(--ink); text-decoration-color: var(--line-strong); text-underline-offset: 3px; font-weight: 700; line-height: 1.35; }
.sources a:hover { color: var(--link); text-decoration-color: currentColor; }
.sources svg { display: inline-block; width: 14px; height: 14px; color: var(--muted); margin-left: 6px; vertical-align: -1px; }
.sources .nowrap { white-space: nowrap; }
.src-meta { display: block; margin-top: 3px; font-size: 0.875rem; color: var(--muted); font-variant-numeric: tabular-nums; }
.empty { padding: 48px 0; color: var(--muted); display: none; }
.empty.show { display: block; }
.note-box { background: var(--glass); border-radius: 16px; padding: 22px 26px; box-shadow: var(--shadow); max-width: 68ch; }
.note-box p:last-child { margin: 0; }

/* story page */
.story-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 68ch) minmax(0, 1fr); }
.story-grid > * { grid-column: 2; }
.story-body p { font-size: 1.1875rem; line-height: 1.7; }
.story-body p:first-of-type::first-line { font-weight: 700; }
.story-body .dated { font-family: var(--display); font-weight: 800; font-size: 1rem; color: var(--navy); display: block; margin: 40px 0 10px; font-variant-numeric: tabular-nums; }
.story-body blockquote { margin: 48px 0; font-family: var(--display); font-weight: 700; font-size: clamp(1.6rem, 3vw, 2.4rem); line-height: 1.15; color: var(--navy); letter-spacing: -0.02em; }
.threshold-rule { height: 3px; background: linear-gradient(90deg, var(--line-strong) 0 50%, var(--cyan) 50% 100%); margin: 48px 0; position: relative; }
.threshold-rule::after { content: ""; position: absolute; left: 50%; top: -24px; width: 14px; height: 18px; margin-left: -7px; background: var(--cyan); border-radius: 50% 50% 50% 50% / 62% 62% 38% 38%; transform: rotate(180deg); }

/* videos */
.videos { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: clamp(24px, 4vw, 48px); }
.video h2 { font-size: 1.5rem; margin: 16px 0 6px; }
.video p { color: var(--muted); margin: 0; }
.player { position: relative; aspect-ratio: 16 / 9; border-radius: 16px; overflow: hidden; background: #0a2b52; box-shadow: var(--shadow); }
.player button { position: absolute; inset: 0; border: 0; padding: 0; cursor: pointer; background: #0a2b52; display: block; width: 100%; }
.player img { width: 100%; height: 100%; object-fit: cover; opacity: 0.9; transition: opacity 300ms, transform 600ms var(--ease-out); }
.player button:hover img { opacity: 1; transform: scale(1.02); }
.player .play { position: absolute; left: 50%; top: 50%; translate: -50% -50%; width: 76px; height: 76px; border-radius: 50%; background: var(--glass); color: var(--navy); display: grid; place-items: center; box-shadow: 0 10px 30px -10px rgba(0,0,0,0.6); }
.player .play svg { width: 30px; height: 30px; margin-left: 4px; }
.player iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.player .consent { position: absolute; left: 12px; bottom: 12px; right: 12px; color: #fff; font-size: 0.875rem; text-shadow: 0 1px 3px rgba(0,0,0,0.7); text-align: left; }

/* athletes */
.roster { list-style: none; margin: 0; padding: 0; columns: 2 300px; column-gap: 48px; }
.roster li { break-inside: avoid; padding: 14px 0; border-bottom: 1px solid var(--line); display: flex; justify-content: space-between; gap: 16px; }
.roster strong { font-family: var(--display); font-size: 1.25rem; letter-spacing: -0.01em; }
.roster span { color: var(--muted); text-align: right; }

/* ---------- footer ---------- */
.site-foot { background: var(--glass); border-top: 1px solid var(--line); }
.foot-grid { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr) minmax(0, 1.4fr); gap: 40px; padding: 56px 0 40px; }
.foot-grid img { height: 64px; width: auto; margin-bottom: 14px; }
.foot-grid h2 { font-size: 1rem; font-weight: 800; margin-bottom: 12px; }
.foot-grid ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; }
.foot-grid a { color: var(--ink); text-decoration: none; }
.foot-grid a:hover { color: var(--link); text-decoration: underline; }
.socials { display: flex; gap: 10px; margin-top: 16px; }
.socials a { width: 44px; height: 44px; border-radius: 50%; border: 1px solid var(--line-strong); display: grid; place-items: center; color: var(--navy); }
.socials a:hover { background: var(--navy); color: #fff; border-color: var(--navy); }
.socials svg { width: 20px; height: 20px; }
.disclaimer { font-size: 0.875rem; color: var(--muted); line-height: 1.55; }
.foot-base { border-top: 1px solid var(--line); padding: 18px 0 28px; font-size: 0.875rem; color: var(--muted); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }

/* ---------- responsive ---------- */
@media (max-width: 980px) {
  .hero .wrap, .equation, .close-grid, .two-col { grid-template-columns: 1fr; }
  .hero-copy { padding-top: 0; }
  .frames { grid-template-columns: repeat(3, minmax(0, 1fr)); row-gap: 36px; }
  .uses { grid-template-columns: 1fr; }
  .sci-topic { grid-template-columns: 1fr; gap: 12px; }
  .foot-grid { grid-template-columns: 1fr 1fr; }
  .foot-grid > :last-child { grid-column: 1 / -1; }
  .videos { grid-template-columns: 1fr; }
}
@media (max-width: 860px) {
  .menu-toggle {
    display: inline-flex; align-items: center; gap: 8px; background: none; border: 2px solid var(--line-strong);
    border-radius: 999px; padding: 8px 14px; font: inherit; font-family: var(--display); font-weight: 700; color: var(--ink); cursor: pointer;
  }
  .menu-toggle svg { width: 20px; height: 20px; }
  .nav {
    display: none; position: absolute; top: 100%; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--bench); border-bottom: 1px solid var(--line); padding: 8px var(--gutter) 20px;
  }
  .nav.open { display: flex; }
  .nav a { padding: 14px 4px; border-bottom: 1px solid var(--line); border-radius: 0; font-size: 1.125rem; }
  .nav a[aria-current="page"] { box-shadow: none; font-weight: 800; background: color-mix(in srgb, var(--cyan) 12%, transparent); padding-left: 12px; }
  .nav .btn { margin: 16px 0 0; justify-content: center; border-radius: 999px; }
  .brand img { height: 46px; }
  .site-head .wrap { min-height: 66px; }
  .mini-rack { top: 66px; }
}
@media (max-width: 560px) {
  body { font-size: 1.0625rem; }
  .rack { --tube-w: 34px; --tube-h: 210px; padding-top: 20px; }
  .rack::after { bottom: 52px; }
  .tube .ph { height: 52px; font-size: 0.875rem; }
  .frames { grid-template-columns: 1fr; row-gap: 0; }
  .frames li { border-top: 0; padding: 0 0 26px 24px; background: linear-gradient(var(--line-strong), var(--line-strong)) 0 0 / 3px 100% no-repeat; }
  .frames li.after { background-image: linear-gradient(var(--cyan), var(--cyan)); }
  .frames li::before { top: 2px; left: -6px; }
  .frames li.threshold::after { top: -6px; left: -33px; transform: rotate(-90deg); }
  .pull { grid-template-columns: 1fr; }
  .research-head { grid-template-columns: 1fr; }
  .foot-grid { grid-template-columns: 1fr; }
  .roster li { flex-direction: column; gap: 2px; }
  .roster span { text-align: left; }
  .hero { padding-top: 20px; }
  .hero h1 { font-size: 2.25rem; margin-bottom: 16px; }
  .hero .lede { font-size: 1.0625rem; margin-bottom: 20px; }
  .hero .actions { flex-wrap: nowrap; margin-bottom: 24px; }
  .hero .actions .btn { flex: 1 1 auto; justify-content: center; padding: 13px 16px; }
  .hero .actions .long { display: none; }
  .hero .actions { margin-bottom: 12px; }
  .hero .phone-line { margin-bottom: 20px; font-size: 0.9375rem; }
  .hero .wrap { gap: 0; }
  .rack { --tube-h: 150px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 1ms !important; transition-duration: 1ms !important; transition-delay: 0ms !important; }
  .tube .drop { display: none; }
}