/* ==========================================================
   Opensee — open-see.org
   Palette: background #F6F8FB · accent #2C2C2D
   ========================================================== */

/* ---------- Tokens ---------- */
:root {
  --bg: #F6F8FB;
  --surface: #FFFFFF;
  --raised: #EDF0F5;
  --border: #DCE1E9;
  --line: #C9D0DB;
  --text: #1B1C1E;
  --muted: #687080;
  --accent: #2C2C2D;
  --on-accent: #F6F8FB;
  --radius: 6px;
  --top-h: 68px;
}

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

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

html,
body {
  margin: 0;
  background: #F6F8FB;
  color: var(--text);
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }

h1, h2, h3 { margin: 0; line-height: 1.15; letter-spacing: -0.02em; color: var(--accent); }

p { margin: 0; }

/* ---------- Wrapper ---------- */
.lane {
  width: 100%;
  max-width: 1040px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 15px 24px;
  border-radius: var(--radius);
  background: var(--accent);
  color: var(--on-accent);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  white-space: nowrap;
  transition: background 0.15s ease, transform 0.15s ease;
}
.btn:hover { background: #000000; }
.btn:active { transform: translateY(1px); }
.btn svg { width: 17px; height: 17px; fill: currentColor; flex-shrink: 0; }
.btn-sm { padding: 9px 16px; font-size: 13px; gap: 7px; }
.btn-sm svg { width: 14px; height: 14px; }

/* ---------- Header ---------- */
.top {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(246, 248, 251, 0.94);
  border-bottom: 1px solid var(--border);
  -webkit-backdrop-filter: saturate(160%) blur(10px);
  backdrop-filter: saturate(160%) blur(10px);
}

.top-in {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--top-h);
  gap: 16px;
}

/* The logo file is a white wordmark with generous padding:
   crop the padding and tint it to the accent colour. */
.logo {
  display: block;
  width: 124px;
  height: 24px;
  overflow: hidden;
  flex-shrink: 0;
}
.logo img {
  width: 144px;
  height: 60px;
  max-width: none;
  margin: -19px 0 0 -9.6px;
  filter: brightness(0.173);
}

.nav {
  display: none;
  position: absolute;
  top: var(--top-h);
  left: -20px;
  right: -20px;
  background: var(--bg);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 8px 0 16px;
}
.nav.open { display: block; }

.nav-in { display: flex; flex-direction: column; padding: 0 20px; }
.nav-in a {
  padding: 12px 0;
  color: var(--muted);
  font-size: 15px;
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px solid var(--border);
}
.nav-in a:last-child { border-bottom: 0; }
.nav-in a:hover,
.nav-in a.on { color: var(--accent); }

.top-right { display: flex; align-items: center; gap: 10px; }

.burger {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 38px;
  height: 38px;
  padding: 0 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  cursor: pointer;
}
.burger span { display: block; height: 1.5px; background: var(--accent); border-radius: 1px; }

/* ---------- Eyebrow / section heads ---------- */
.eyebrow {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 2.8px;
  text-transform: uppercase;
  color: var(--accent);
}

.head { margin-bottom: 36px; max-width: 620px; }
.head h2 { margin-top: 12px; font-size: clamp(1.6rem, 3.6vw, 2.3rem); font-weight: 700; }
.head p { margin-top: 12px; color: var(--muted); }

.sec { padding: 72px 0; }

/* ---------- Home: typographic opener ---------- */
.open {
  padding: 64px 0 48px;
  border-bottom: 1px solid var(--border);
}
.open h1 {
  margin-top: 18px;
  max-width: 880px;
  font-size: clamp(2.3rem, 6.4vw, 4.4rem);
  font-weight: 700;
  letter-spacing: -0.035em;
  line-height: 1.04;
}
.open h1 em { font-style: normal; color: var(--muted); }

.open-foot {
  display: flex;
  flex-direction: column;
  gap: 24px;
  margin-top: 32px;
}
.open-foot p { max-width: 520px; color: var(--muted); font-size: 17px; }

/* Network strip under the opener */
.nets {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  margin-top: 48px;
  border-top: 1px solid var(--border);
  border-left: 1px solid var(--border);
}
.nets div {
  padding: 14px 16px;
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
}
.nets small {
  display: block;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 1.6px;
  text-transform: uppercase;
  color: var(--muted);
}

/* ---------- Home: showcase band (icon + chart mock) ---------- */
.show {
  display: grid;
  gap: 20px;
}

.show-icon {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 24px;
  padding: 28px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
}
.show-icon .tile {
  width: 112px;
  height: 112px;
  border-radius: 26px;
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(44, 44, 45, 0.14);
}
/* The icon file has a thin frame baked in — scale past it */
.show-icon .tile img { width: 100%; height: 100%; transform: scale(1.12); }
.show-icon h3 { font-size: 20px; }
.show-icon p { margin-top: 8px; color: var(--muted); font-size: 15px; }

/* Candle chart mock — illustrative only */
.board {
  padding: 22px 22px 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
}
.board-top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}
.board-top b { font-size: 15px; color: var(--accent); }
.board-top span { font-size: 12px; color: var(--muted); }

.tabs { display: flex; gap: 6px; margin-top: 14px; flex-wrap: wrap; }
.tabs span {
  padding: 4px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 500;
  color: var(--muted);
}
.tabs span.on { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }

.candles {
  position: relative;
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 4px;
  height: 180px;
  margin-top: 18px;
  padding-top: 6px;
  background-image: linear-gradient(var(--raised) 1px, transparent 1px);
  background-size: 100% 45px;
  border-bottom: 1px solid var(--line);
}
.c {
  position: relative;
  flex: 1;
}
/* wick */
.c::before {
  content: "";
  position: absolute;
  left: 50%;
  width: 1px;
  margin-left: -0.5px;
  top: var(--wt);
  bottom: var(--wb);
  background: var(--accent);
}
/* body */
.c::after {
  content: "";
  position: absolute;
  left: 18%;
  right: 18%;
  top: var(--bt);
  bottom: var(--bb);
  border: 1.5px solid var(--accent);
  border-radius: 2px;
  background: var(--surface);
}
.c.dn::after { background: var(--accent); }

.board-foot {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin-top: 16px;
}
.board-foot div { padding: 10px 12px; background: var(--raised); border-radius: 8px; }
.board-foot small { display: block; font-size: 11px; color: var(--muted); }
.board-foot b { font-size: 13px; color: var(--accent); }

.note { margin-top: 12px; font-size: 12px; color: var(--muted); }

/* ---------- Home: numbered features ---------- */
.nums {
  display: grid;
  border-top: 1px solid var(--border);
}
.num {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 4px 16px;
  padding: 26px 0;
  border-bottom: 1px solid var(--border);
}
.num i {
  grid-row: span 2;
  font-style: normal;
  font-size: 30px;
  font-weight: 300;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--line);
}
.num h3 { font-size: 18px; font-weight: 600; }
.num p { color: var(--muted); font-size: 15px; }

/* ---------- Home: how it works strip ---------- */
.flow {
  display: grid;
  gap: 12px;
}
.flow div {
  padding: 22px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
}
.flow span {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--muted);
}
.flow h3 { margin-top: 10px; font-size: 17px; }
.flow p { margin-top: 6px; color: var(--muted); font-size: 14px; }

/* ---------- Home: stat columns ---------- */
.stats {
  display: grid;
  background: var(--accent);
  border-radius: 14px;
  color: var(--on-accent);
  overflow: hidden;
}
.stat {
  padding: 30px 28px;
  border-bottom: 1px solid rgba(246, 248, 251, 0.14);
}
.stat:last-child { border-bottom: 0; }
.stat b {
  display: block;
  font-size: 44px;
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1;
}
.stat span { display: block; margin-top: 10px; font-size: 14px; color: rgba(246, 248, 251, 0.7); }

/* ---------- Home: closing CTA ---------- */
.lane.close {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 22px;
  padding-top: 8px;
  padding-bottom: 80px;
}
.close h2 { font-size: clamp(1.6rem, 4vw, 2.4rem); max-width: 600px; }

/* ---------- Inner pages ---------- */
.lane.intro { padding-top: 56px; padding-bottom: 32px; }
.intro h1 { margin-top: 14px; font-size: clamp(2rem, 5vw, 3rem); font-weight: 700; }
.intro p { margin-top: 12px; max-width: 580px; color: var(--muted); }

.cards { display: grid; gap: 14px; }

.card {
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
}
.card h2 { font-size: 17px; font-weight: 600; letter-spacing: -0.01em; }
.card h2 small {
  display: block;
  margin-bottom: 6px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--muted);
}
.card p,
.card li { color: var(--muted); font-size: 15px; }
.card p + p { margin-top: 10px; }
.card h2 + p,
.card h2 + ul { margin-top: 10px; }
.card ul { margin: 10px 0 0; padding-left: 18px; }
.card li + li { margin-top: 4px; }

.card.dark { background: var(--accent); border-color: var(--accent); }
.card.dark h2,
.card.dark h2 small,
.card.dark p { color: var(--on-accent); }
.card.dark p { opacity: 0.78; }
.card.dark a { color: var(--on-accent); font-weight: 600; }

.pair { display: grid; gap: 14px; margin-top: 14px; }

.meta { margin-top: 28px; padding-bottom: 72px; font-size: 13px; color: var(--muted); }

/* ---------- Footer ---------- */
.foot {
  border-top: 1px solid var(--border);
  background: var(--surface);
}
.lane.foot-in {
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding-top: 32px;
  padding-bottom: 32px;
}
.foot-links { display: flex; flex-wrap: wrap; gap: 8px 22px; }
.foot-links a { color: var(--muted); font-size: 14px; text-decoration: none; }
.foot-links a:hover { color: var(--accent); }
.foot-copy { font-size: 13px; color: var(--muted); }

/* ==========================================================
   Tablet and up
   ========================================================== */
@media (min-width: 640px) {
  .nets { grid-template-columns: repeat(5, 1fr); }
  .flow { grid-template-columns: repeat(3, 1fr); }
  .stats { grid-template-columns: repeat(3, 1fr); }
  .stat { border-bottom: 0; border-right: 1px solid rgba(246, 248, 251, 0.14); }
  .stat:last-child { border-right: 0; }
  .pair { grid-template-columns: 1fr 1fr; }
  .cards.two { grid-template-columns: 1fr 1fr; }
  .nums { grid-template-columns: 1fr 1fr; column-gap: 40px; }
}

@media (min-width: 760px) {
  .lane { padding: 0 32px; }
  .burger { display: none; }
  .nav {
    display: block;
    position: static;
    border: 0;
    background: transparent;
    padding: 0;
    margin-left: auto;
  }
  .nav-in { flex-direction: row; gap: 26px; padding: 0; }
  .nav-in a { padding: 0; border: 0; font-size: 14px; }
  .top-right { margin-left: 14px; }
}

@media (min-width: 900px) {
  .open { padding: 96px 0 64px; }
  .open-foot { flex-direction: row; align-items: flex-end; justify-content: space-between; }
  .show { grid-template-columns: 5fr 7fr; }
  .sec { padding: 96px 0; }
  .nums { grid-template-columns: repeat(3, 1fr); }
  .lane.close { flex-direction: row; align-items: center; justify-content: space-between; }
  .lane.foot-in { flex-direction: row; align-items: center; justify-content: space-between; }
}