:root {
  --ink: #111417;
  --muted: #687077;
  --paper: #fbfbfa;
  --mist: #eef1f2;
  --silver: #c8d0d4;
  --steel: #758087;
  --night: #111419;
  --blue: #0878e7;
  --line: rgba(17, 20, 23, 0.12);
  --max: 1180px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Inter, "SF Pro Display", "PingFang SC", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

.site-header {
  position: fixed;
  z-index: 10;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 52px;
  padding: 0 5vw;
  color: #fff;
  transition: background 220ms ease, color 220ms ease, box-shadow 220ms ease;
}

.site-header.is-scrolled {
  color: var(--ink);
  background: rgba(251, 251, 250, 0.78);
  box-shadow: 0 1px 0 rgba(17, 20, 23, 0.08);
  backdrop-filter: blur(18px);
}

.wordmark { font-size: 16px; font-weight: 680; letter-spacing: -0.03em; }
.site-nav { display: flex; align-items: center; gap: clamp(16px, 2.5vw, 34px); font-size: 12px; }
.site-nav a { opacity: 0.84; transition: opacity 180ms ease; }
.site-nav a:hover { opacity: 1; }
.site-nav .nav-cta { padding: 7px 12px; border-radius: 999px; color: #fff; background: var(--blue); opacity: 1; }
.menu-toggle { display: none; border: 0; color: inherit; background: transparent; font: inherit; cursor: pointer; }

.hero,
.story-section,
.battery-section,
.specs-section {
  scroll-margin-top: 52px;
}

.hero {
  min-height: 100svh;
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(360px, 1.08fr);
  align-items: center;
  gap: 24px;
  padding: 100px max(5vw, calc((100vw - var(--max)) / 2)) 56px;
  overflow: hidden;
  color: #fff;
  background: radial-gradient(circle at 71% 47%, #66727a 0, #2a3137 31%, #111419 67%);
}

.hero-copy, .story-copy, .battery-copy { position: relative; z-index: 2; }
.eyebrow { margin: 0 0 14px; font-size: 12px; font-weight: 650; letter-spacing: 0.12em; text-transform: uppercase; }
.hero .eyebrow { color: #b5c9dc; }
h1, h2, p { margin-top: 0; }
h1 { margin-bottom: 15px; font-size: clamp(58px, 8vw, 110px); line-height: 0.94; letter-spacing: -0.075em; }
h2 { margin-bottom: 20px; font-size: clamp(38px, 5vw, 68px); line-height: 0.98; letter-spacing: -0.065em; }
.hero-line { max-width: 330px; margin-bottom: 29px; color: #dce2e4; font-size: clamp(18px, 2vw, 23px); line-height: 1.45; }
.hero-actions { display: flex; align-items: center; gap: 22px; font-size: 15px; }
.button { display: inline-flex; align-items: center; justify-content: center; padding: 11px 18px; border-radius: 999px; font-weight: 600; }
.button-primary { color: white; background: var(--blue); transition: transform 180ms ease, background 180ms ease; }
.button-primary:hover { transform: translateY(-1px); background: #1d8cf6; }
.text-link { color: #70baff; }

.product-stage { position: relative; min-height: 550px; }
.product-stage-hero { display: flex; align-items: center; justify-content: flex-end; }
.hero-product-image {
  width: 140%;
  max-width: 760px;
  height: auto;
  margin-right: -10%;
  object-fit: contain;
  filter: drop-shadow(0 24px 32px rgba(0, 0, 0, 0.22));
}
.story-section,
.battery-section {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: center;
  min-height: min(760px, 85svh);
  gap: clamp(36px, 7vw, 120px);
  padding: 88px max(5vw, calc((100vw - var(--max)) / 2));
  overflow: hidden;
}

.story-copy { max-width: 490px; }
.story-copy > p:not(.eyebrow), .battery-copy > p:not(.eyebrow) { max-width: 410px; color: var(--muted); font-size: 18px; line-height: 1.58; }
.story-light { background: linear-gradient(132deg, #fff 0%, #eef2f3 100%); }
.story-dark { color: #f6f7f7; background: #151a20; }
.story-dark .story-copy > p:not(.eyebrow) { color: #bfc7ce; }
.story-dark .eyebrow { color: #7bb8f4; }
.story-silver { background: #e3e8e9; }
.story-scene {
  display: flex;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}
.story-scene-noise { background-color: #eef1f2; background-image: url("assets/vela-noise-scene.jpg"); }
.story-scene-spatial { justify-content: flex-end; background-color: #151a20; background-image: url("assets/vela-spatial-scene.jpg"); }
.story-scene-comfort { position: relative; display: block; background-color: #e3e8e9; background-image: url("assets/vela-comfort-scene.jpg"); }
.story-scene-comfort .story-copy { position: absolute; top: clamp(64px, 7vw, 112px); right: 7vw; width: min(38vw, 560px); }
.story-scene-comfort h2 { font-size: clamp(42px, 3.6vw, 56px); }

.battery-section { color: #f8fafb; background: radial-gradient(circle at 70% 40%, #34424c, #12161b 59%); }
.battery-copy > p:not(.eyebrow) { color: #c6d0d6; }
.battery-copy .eyebrow { color: #83c5ff; }
.battery-number { display: flex; align-items: center; gap: 14px; margin-top: 30px; }
.battery-number strong { font-size: clamp(86px, 11vw, 150px); font-weight: 650; line-height: 0.75; letter-spacing: -0.09em; }
.battery-number span { color: #c6d0d6; font-size: 15px; line-height: 1.3; }
.case-stage { position: relative; min-height: 420px; }
.charging-case { position: absolute; left: 50%; top: 50%; width: 310px; height: 230px; border-radius: 110px 110px 88px 88px; background: linear-gradient(125deg, #fff, #d8e0e3 48%, #9aa8ae); box-shadow: inset -22px -24px 36px rgba(74, 90, 96, 0.28), 28px 38px 50px rgba(0, 0, 0, 0.35); transform: translate(-50%, -50%) rotate(-12deg); }
.case-seam { position: absolute; top: 93px; left: 9px; right: 9px; height: 2px; background: rgba(73, 92, 99, 0.27); }
.case-light { position: absolute; left: 50%; bottom: 54px; width: 7px; height: 7px; border-radius: 50%; background: #5de685; box-shadow: 0 0 11px #5de685; }

.specs-section { padding: 120px max(5vw, calc((100vw - var(--max)) / 2)); background: #fff; }
.specs-section > h2 { max-width: 560px; }
.spec-grid { display: grid; grid-template-columns: repeat(4, 1fr); margin: 52px 0 0; border-top: 1px solid var(--line); }
.spec-grid div { min-height: 135px; padding: 24px 18px 18px 0; border-bottom: 1px solid var(--line); }
.spec-grid div + div { padding-left: 18px; border-left: 1px solid var(--line); }
dt { margin-bottom: 12px; color: var(--muted); font-size: 13px; }
dd { margin: 0; font-size: 17px; font-weight: 620; line-height: 1.35; }
.spec-note { margin-top: 22px; color: var(--muted); font-size: 13px; }

.site-footer { display: flex; justify-content: space-between; gap: 20px; padding: 28px 5vw; color: #aeb7bd; background: #111419; font-size: 12px; }
.site-footer p { margin: 0; }

.reveal { opacity: 0; transform: translateY(18px); transition: opacity 650ms ease, transform 650ms ease; }
.reveal.is-visible { opacity: 1; transform: translateY(0); }

@media (max-width: 700px) {
  .site-header { min-height: 48px; padding: 0 22px; }
  .menu-toggle { display: block; padding: 10px 0; font-size: 12px; }
  .site-nav { position: absolute; top: 48px; left: 14px; right: 14px; display: none; flex-direction: column; align-items: stretch; gap: 0; padding: 10px; color: var(--ink); background: rgba(252, 252, 251, 0.96); border-radius: 14px; box-shadow: 0 12px 34px rgba(0, 0, 0, 0.13); backdrop-filter: blur(18px); }
  .site-nav.is-open { display: flex; }
  .site-nav a { padding: 12px; }
  .site-nav .nav-cta { margin-top: 4px; text-align: center; }
  .hero { grid-template-columns: 1fr; align-content: center; min-height: 760px; gap: 0; padding: 94px 26px 42px; }
  h1 { font-size: clamp(58px, 19vw, 78px); }
  h2 { font-size: clamp(38px, 12vw, 54px); }
  .hero-line { font-size: 18px; }
  .product-stage { min-height: 350px; margin: 8px -28px -24px; }
  .hero-product-image { width: 128%; max-width: 560px; margin-right: -13%; }
  .story-section, .battery-section { grid-template-columns: 1fr; min-height: 0; gap: 28px; padding: 82px 26px; }
  .story-scene { min-height: 0; padding-top: min(72vw, 360px); background-position: center top; background-size: 100% auto; }
  .story-scene-spatial, .story-scene-comfort { justify-content: flex-start; }
  .story-scene-comfort { display: flex; }
  .story-scene-comfort .story-copy { position: static; width: auto; }
  .story-scene-comfort h2 { font-size: clamp(38px, 12vw, 54px); }
  .story-copy > p:not(.eyebrow), .battery-copy > p:not(.eyebrow) { font-size: 16px; }
  .case-stage { min-height: 310px; }
  .charging-case { width: 250px; height: 185px; }
  .case-seam { top: 75px; }
  .case-light { bottom: 42px; }
  .specs-section { padding: 82px 26px; }
  .spec-grid { grid-template-columns: repeat(2, 1fr); margin-top: 36px; }
  .spec-grid div:nth-child(3) { padding-left: 0; border-left: 0; }
  .spec-grid div { min-height: 118px; }
  .site-footer { flex-direction: column; padding: 26px; gap: 9px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
  .reveal { opacity: 1; transform: none; }
}