/* ================================================================
   EWELL BIOTECH — Brand VI System
   广州誉维生物 — VI手册1015规范
   ================================================================ */

@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;700;900&family=Inter:wght@300;400;500;600;700&display=swap');

/* ---------- Design Tokens (VI Colors) ---------- */
:root {
  /* Primary: 誉维红 (70% usage) */
  --ewell-red: #F33829;
  --ewell-red-dark: #AF2734;
  --ewell-red-coral: #FF6D60;
  --ewell-red-pink: #FFDFDD;

  /* Auxiliary: 雪青色 (Priority) */
  --aux-snow: #454975;
  --aux-snow-light: #6E709C;
  --aux-snow-pale: #BCC0CE;

  /* Other Auxiliary */
  --aux-gold: #F1B658;
  --aux-gold-light: #F2CA8F;
  --aux-warm-gray: #DCD1C8;
  --aux-gray: #B3B3B3;

  /* Neutral */
  --ink: #1A1A1A;
  --ink-soft: #4A4A4A;
  --paper: #FFFFFF;
  --paper-warm: #FAFAFA;
  --paper-cool: #F5F5F5;
  --divider: #E8E8E8;
  --line-strong: #2A2A2A;

  /* Red gradient (from VI) */
  --grad-red: linear-gradient(135deg, #F33829 0%, #FF6D60 100%);
  --grad-snow: linear-gradient(135deg, #454975 0%, #6E709C 100%);

  /* Typography (VI: HarmonyOS Sans SC) */
  --font-zh: 'HarmonyOS Sans SC', 'PingFang SC', 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
  --font-en: 'Inter', 'Helvetica Neue', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Fluid type scale */
  --fs-hero: clamp(2.5rem, 5.5vw, 4.5rem);
  --fs-h1: clamp(2rem, 4vw, 3.2rem);
  --fs-h2: clamp(1.5rem, 2.8vw, 2.2rem);
  --fs-h3: clamp(1.1rem, 1.8vw, 1.4rem);
  --fs-body: 1rem;
  --fs-small: 0.875rem;
  --fs-tiny: 0.75rem;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 2rem;
  --space-lg: 4rem;
  --space-xl: 6rem;

  /* Layout */
  --container: 1280px;
  --radius-sm: 2px;
  --radius-md: 4px;

  /* Motion */
  --ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --dur-fast: 0.25s;
  --dur-med: 0.5s;
  --dur-slow: 1s;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
  font-family: var(--font-zh);
  font-size: var(--fs-body);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.7;
  overflow-x: hidden;
  font-weight: 400;
}
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }

/* ---------- Container & Layout ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 clamp(1.2rem, 4vw, 3rem);
}
.section { padding: var(--space-xl) 0; position: relative; }
.section-tight { padding: var(--space-lg) 0; }

/* ---------- Typography ---------- */
h1, h2, h3, h4 {
  font-family: var(--font-zh);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.h-hero { font-size: var(--fs-hero); font-weight: 900; line-height: 1.1; letter-spacing: -0.02em; }
.h1 { font-size: var(--fs-h1); font-weight: 700; }
.h2 { font-size: var(--fs-h2); font-weight: 700; }
.h3 { font-size: var(--fs-h3); font-weight: 500; }

.font-en { font-family: var(--font-en); }
.font-mono { font-family: var(--font-mono); }

/* VI eyebrow label — minimalist with horizontal line */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-en);
  font-size: var(--fs-small);
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ewell-red);
  margin-bottom: 1.5rem;
}
.eyebrow::before {
  content: '';
  width: 36px;
  height: 1px;
  background: var(--ewell-red);
}
.eyebrow-dark { color: var(--ink); }
.eyebrow-dark::before { background: var(--ink); }

.lead {
  font-size: 1.05rem;
  color: var(--ink-soft);
  line-height: 1.8;
  font-weight: 400;
}
.text-center { text-align: center; }
.text-red { color: var(--ewell-red); }
.text-snow { color: var(--aux-snow); }
.text-muted { color: var(--ink-soft); }

/* ---------- VI Divider ---------- */
.vi-divider {
  height: 1px;
  background: var(--divider);
  margin: 2rem 0;
}
.vi-divider-dark {
  height: 1px;
  background: var(--line-strong);
  margin: 2rem 0;
}

/* ---------- Seal Logo SVG ---------- */
.seal-logo { display: inline-block; vertical-align: middle; }
.seal-logo svg { display: block; }

/* ---------- Navigation (Minimal Eastern) ---------- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  padding: 1.25rem 0;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(12px) saturate(160%);
  -webkit-backdrop-filter: blur(12px) saturate(160%);
  border-bottom: 1px solid transparent;
  transition: all var(--dur-med) var(--ease-out-quart);
}
.nav.scrolled {
  border-bottom-color: var(--divider);
  padding: 0.8rem 0;
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-shrink: 0;
}
.nav-brand .seal-mark {
  width: 40px; height: 40px;
  display: block;
  flex-shrink: 0;
}
.nav-brand .brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.nav-brand .brand-name {
  font-family: var(--font-zh);
  font-weight: 700;
  font-size: 1rem;
  color: var(--ink);
  letter-spacing: 0.02em;
  white-space: nowrap;
}
.nav-brand .brand-tag {
  font-family: var(--font-en);
  font-size: 0.7rem;
  color: var(--ewell-red);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  font-weight: 500;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.15rem;
  white-space: nowrap;
}
.nav-links a {
  padding: 0.5rem 0.9rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink-soft);
  border-radius: 0;
  transition: color var(--dur-fast) var(--ease-out-quart);
  position: relative;
}
.nav-links a:hover { color: var(--ewell-red); }
.nav-links a.active { color: var(--ink); font-weight: 700; }
.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background: var(--ewell-red);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1.1rem;
  border: 1.5px solid var(--ink);
  color: var(--ink);
  font-weight: 500;
  font-size: 0.85rem;
  border-radius: 0;
  transition: all var(--dur-fast) var(--ease-out-quart);
  white-space: nowrap;
  flex-shrink: 0;
}
.nav-cta:hover {
  background: var(--ink);
  color: var(--paper);
}
.nav-toggle { display: none; }

/* ---------- Buttons (Minimal Square) ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1.8rem;
  font-family: var(--font-zh);
  font-weight: 500;
  font-size: 0.95rem;
  border-radius: 0;
  transition: all var(--dur-fast) var(--ease-out-quart);
  position: relative;
  white-space: nowrap;
  letter-spacing: 0.02em;
}
.btn-primary {
  background: var(--ewell-red);
  color: var(--paper);
}
.btn-primary:hover {
  background: var(--ink);
  transform: translateY(-2px);
}
.btn-outline {
  border: 1.5px solid var(--ink);
  color: var(--ink);
  background: transparent;
}
.btn-outline:hover {
  background: var(--ink);
  color: var(--paper);
}
.btn-outline-red {
  border: 1.5px solid var(--ewell-red);
  color: var(--ewell-red);
  background: transparent;
}
.btn-outline-red:hover {
  background: var(--ewell-red);
  color: var(--paper);
}
.btn-text {
  padding: 0;
  color: var(--ink);
  border-bottom: 1px solid var(--ink);
  padding-bottom: 0.2rem;
}
.btn-text:hover { color: var(--ewell-red); border-color: var(--ewell-red); }
.btn-arrow { transition: transform var(--dur-fast) var(--ease-out-quart); }
.btn:hover .btn-arrow { transform: translateX(4px); }

/* ---------- Hero (Minimal Eastern) ---------- */
.hero {
  position: relative;
  padding: 9rem 0 5rem;
  background: var(--paper);
  overflow: hidden;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 4rem;
  align-items: center;
}
.hero-content h1 {
  margin-bottom: 1.5rem;
}
.hero-content .lead {
  max-width: 540px;
  margin-bottom: 2.5rem;
}
.hero-visual {
  position: relative;
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}
.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ---------- Section Headers ---------- */
.section-header {
  max-width: 680px;
  margin-bottom: 4rem;
}
.section-header.center { margin-left: auto; margin-right: auto; text-align: center; }
.section-header .lead { margin-top: 1rem; }

/* ---------- Cards (Minimal) ---------- */
.card {
  background: var(--paper);
  border: 1px solid var(--divider);
  padding: 2rem;
  transition: all var(--dur-med) var(--ease-out-quart);
  position: relative;
  overflow: hidden;
}
.card:hover {
  border-color: var(--ink);
  transform: translateY(-4px);
  box-shadow: 0 10px 30px rgba(26, 26, 26, 0.06);
}
.card-label {
  font-family: var(--font-en);
  font-size: var(--fs-tiny);
  color: var(--ewell-red);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 1rem;
  font-weight: 600;
}
.card h3 { margin-bottom: 0.6rem; }
.card-num {
  font-family: var(--font-en);
  font-size: 3rem;
  font-weight: 300;
  color: var(--ewell-red);
  line-height: 1;
  margin-bottom: 1rem;
}

/* ---------- Auxiliary Graphics (Seal Fragments) ---------- */
.aux-graphics {
  position: absolute;
  pointer-events: none;
  z-index: 0;
}
.aux-graphics-frag {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 4px;
  width: 120px;
}
.aux-graphics-frag div {
  width: 20px; height: 20px;
  background: var(--ewell-red);
  opacity: 0.85;
}
.aux-graphics-bars-h {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 60px;
}
.aux-graphics-bars-h div {
  height: 8px;
  background: var(--ewell-red);
}
.aux-graphics-bars-v {
  display: flex;
  gap: 4px;
}
.aux-graphics-bars-v div {
  width: 8px;
  height: 60px;
  background: var(--ewell-red);
}
.aux-graphics-corner {
  width: 60px; height: 60px;
  border: 8px solid var(--ewell-red);
  border-right: none;
  border-bottom: none;
}

/* Pattern backgrounds using SVG */
.aux-pattern {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='60' height='60' viewBox='0 0 60 60'%3E%3Crect x='2' y='2' width='12' height='12' fill='%23F33829' opacity='0.7'/%3E%3Crect x='18' y='2' width='12' height='12' fill='%23F33829' opacity='0.4'/%3E%3Crect x='34' y='2' width='12' height='12' fill='%23F33829' opacity='0.7'/%3E%3Crect x='2' y='18' width='12' height='12' fill='%23F33829' opacity='0.4'/%3E%3Crect x='18' y='18' width='12' height='12' fill='%23F33829' opacity='0.7'/%3E%3Crect x='34' y='18' width='12' height='12' fill='%23F33829' opacity='0.4'/%3E%3C/svg%3E");
  background-repeat: repeat;
}

.aux-pattern-bars {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='40' height='40' viewBox='0 0 40 40'%3E%3Crect x='8' y='8' width='24' height='3' fill='%23F33829' opacity='0.6'/%3E%3Crect x='8' y='16' width='24' height='3' fill='%23F33829' opacity='0.8'/%3E%3Crect x='8' y='24' width='24' height='3' fill='%23F33829' opacity='0.6'/%3E%3C/svg%3E");
  background-repeat: repeat;
}

/* ---------- Grid ---------- */
.grid { display: grid; gap: 1.5rem; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-5 { grid-template-columns: repeat(5, 1fr); }

/* ---------- Tag / Pill ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  padding: 0.3rem 0.7rem;
  font-size: var(--fs-tiny);
  font-weight: 500;
  border-radius: 0;
  background: transparent;
  color: var(--ewell-red);
  letter-spacing: 0.05em;
  border: 1px solid var(--ewell-red);
}
.tag-snow {
  color: var(--aux-snow);
  border-color: var(--aux-snow);
}
.tag-solid {
  background: var(--ewell-red);
  color: var(--paper);
  border-color: var(--ewell-red);
}
.tag-outline {
  color: var(--ink);
  border-color: var(--divider);
}

/* ---------- Section Alt Backgrounds (Minimal) ---------- */
.section-alt { background: var(--paper-warm); }
.section-snow { background: var(--aux-snow); color: var(--paper); }
.section-snow h1, .section-snow h2, .section-snow h3 { color: var(--paper); }
.section-snow .lead { color: rgba(255,255,255,0.75); }

/* ---------- Footer (Minimal) ---------- */
.footer {
  background: var(--ink);
  color: rgba(255,255,255,0.6);
  padding: 4rem 0 1.5rem;
  position: relative;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.footer h4 {
  color: var(--paper);
  font-size: 0.9rem;
  margin-bottom: 1rem;
  font-weight: 500;
}
.footer-brand .brand-name { color: var(--paper); }
.footer-brand .brand-tag { color: var(--ewell-red); }
.footer-brand p {
  font-size: 0.85rem;
  line-height: 1.7;
  margin-top: 1rem;
  max-width: 320px;
}
.footer-col ul li { margin-bottom: 0.6rem; }
.footer-col ul li a {
  font-size: 0.88rem;
  transition: color var(--dur-fast);
}
.footer-col ul li a:hover { color: var(--ewell-red-coral); }
.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: rgba(255,255,255,0.4);
}
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a:hover { color: var(--ewell-red); }

/* ---------- Animation Utilities ---------- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--dur-slow) var(--ease-out-expo), transform var(--dur-slow) var(--ease-out-expo);
}
.reveal.in { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ---------- Tabs (Minimal Style) ---------- */
.tabs {
  display: flex;
  gap: 0;
  flex-wrap: wrap;
  margin-bottom: 3rem;
  border-bottom: 1px solid var(--divider);
}
.tab {
  padding: 0.7rem 1.5rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink-soft);
  background: transparent;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: all var(--dur-fast) var(--ease-out-quart);
}
.tab:hover { color: var(--ink); }
.tab.active {
  color: var(--ink);
  border-bottom-color: var(--ewell-red);
  font-weight: 600;
}

/* ---------- Product / News / Promo Cards ---------- */
.product-card,
.news-card,
.promo-card {
  background: var(--paper);
  border: 1px solid var(--divider);
  cursor: pointer;
  transition: all var(--dur-med) var(--ease-out-quart);
  overflow: hidden;
}
.product-card:hover,
.news-card:hover,
.promo-card:hover {
  border-color: var(--ink);
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.06);
}
.product-card-img,
.news-card-banner,
.promo-card-banner {
  background: var(--paper-cool);
  position: relative;
  overflow: hidden;
}

/* ---------- Responsive ---------- */
@media (max-width: 1100px) {
  .nav-links { display: none; }
  .nav-toggle {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 0.5rem;
    cursor: pointer;
  }
  .nav-toggle span {
    width: 22px; height: 1.5px;
    background: var(--ink);
    transition: all var(--dur-fast);
  }
  .nav-toggle.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
  .nav-toggle.open span:nth-child(2) { opacity: 0; }
  .nav-toggle.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%; left: 0; right: 0;
    background: var(--paper);
    padding: 1.5rem;
    border-bottom: 1px solid var(--divider);
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
  }
  .nav-links.open a { padding: 0.7rem 1rem; font-size: 0.95rem; }
}
@media (max-width: 980px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 2rem; }
  .hero-grid { grid-template-columns: 1fr; gap: 2rem; }
}
@media (max-width: 640px) {
  .grid-2, .grid-3, .grid-4, .grid-5 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 1rem; text-align: center; }
  .section { padding: var(--space-lg) 0; }
}

/* ---------- Scroll progress ---------- */
.scroll-progress {
  position: fixed;
  top: 0; left: 0;
  height: 2px;
  width: 0%;
  background: var(--ewell-red);
  z-index: 9999;
  transition: width 0.1s linear;
}

::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: var(--paper-cool); }
::-webkit-scrollbar-thumb { background: var(--aux-snow-pale); border-radius: 0; }
::-webkit-scrollbar-thumb:hover { background: var(--aux-snow); }
::selection { background: var(--ewell-red); color: var(--paper); }