/* ============================================
   ALPHA POWER — Design Brief: eco, clean, tech
   Colors: white, light gray, light green/teal; dark nav
   ============================================ */

:root {
  --color-bg: #f8faf9;
  --color-surface: #ffffff;
  --color-text: #1a2b2a;
  --color-text-muted: #5a6b6a;
  --color-accent: #0d9488;
  --color-accent-light: #ccfbf1;
  --color-nav-bg: #0f172a;
  --color-nav-text: #e2e8f0;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --space-unit: 1rem;
  --container-max: 1200px;
  --header-height: 72px;
  --radius: 8px;
  --shadow: 0 4px 24px rgba(0,0,0,0.06);
  --transition: 0.25s ease;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--color-nav-bg);
  color: var(--color-nav-text);
  box-shadow: var(--shadow);
}
.header-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: var(--space-unit) 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}
.logo {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.02em;
  color: #fff;
  text-decoration: none;
}
.logo-img {
  display: block;
  height: 40px;
  width: auto;
  object-fit: contain;
}
.logo-text { color: inherit; }
.header-badges {
  display: none;
  font-size: 0.75rem;
  opacity: 0.9;
  margin: 0;
}
@media (min-width: 900px) {
  .header-badges {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
  }
}
.nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  color: inherit;
  cursor: pointer;
  padding: 0.5rem;
}
.nav-toggle span {
  width: 22px;
  height: 2px;
  background: currentColor;
  border-radius: 1px;
}
@media (min-width: 768px) {
  .nav-toggle { display: none; }
}
.nav {
  display: none;
  gap: 1.5rem;
  align-items: center;
}
.nav.is-open { display: flex; flex-direction: column; align-items: flex-start; width: 100%; }
@media (min-width: 768px) {
  .nav { display: flex; flex-direction: row; }
  .nav.is-open { flex-direction: row; width: auto; }
}
.nav a {
  color: var(--color-nav-text);
  text-decoration: none;
  font-size: 0.95rem;
  padding: 0.35em 0;
}
.nav a:hover { color: #fff; }
.nav-cta {
  background: var(--color-accent);
  color: #fff !important;
  padding: 0.5em 1em !important;
  border-radius: var(--radius);
}
.nav-cta:hover { opacity: 0.95; }

/* Sections */
.section {
  padding: 4rem 1.5rem;
  max-width: 100%;
}
.section:nth-child(even) { background: var(--color-surface); }
.container {
  max-width: var(--container-max);
  margin: 0 auto;
}
.section-title {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
  color: var(--color-text);
  margin: 0 0 0.5rem;
  letter-spacing: -0.02em;
}
.section-intro {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  margin: 0 0 2.5rem;
  max-width: 640px;
}

/* Hero */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: var(--header-height);
  position: relative;
  text-align: center;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background: url(../assets/images/main_cover.jpg) center / cover no-repeat;
  z-index: 0;
  /* 提亮偏暗的工业场景：整体增亮、略提对比与阴影 */
  filter: brightness(0.9) contrast(1.06) saturate(0.98);
  /* 浅色遮罩保证标题与文案可读，并略增通透感 */
}
.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  /* 白色遮罩：降低下面 rgba 最后一格数字即可减轻“白膜感”（如 0.4→0.25） */
  background:
    radial-gradient(ellipse 85% 55% at 50% 52%, rgba(255,255,255,0.38) 0%, transparent 65%),
    linear-gradient(to bottom, rgba(255,255,255,0.08) 0%, rgba(255,255,255,0.28) 40%, rgba(252,253,253,0.55) 100%);
  z-index: 0;
}
.hero-content {
  position: relative;
  z-index: 1;
  max-width: 720px;
}
.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  color: var(--color-text);
  margin: 0 0 1rem;
  letter-spacing: -0.02em;
  text-shadow: 0 0 24px rgba(255,255,255,0.9), 0 1px 3px rgba(255,255,255,0.6), 0 1px 2px rgba(0,0,0,0.08);
}
.hero-tagline {
  font-size: 1.15rem;
  color: var(--color-text-muted);
  margin: 0 0 2rem;
  line-height: 1.7;
  text-shadow: 0 0 20px rgba(255,255,255,0.85), 0 1px 2px rgba(255,255,255,0.5), 0 1px 1px rgba(0,0,0,0.06);
}
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: opacity var(--transition), transform var(--transition);
}
.btn:hover { opacity: 0.9; transform: translateY(-1px); }
.btn-primary {
  background: var(--color-accent);
  color: #fff;
}

/* Solutions */
.solutions { padding-bottom: 5rem; }
.solution-cards { display: flex; flex-direction: column; gap: 2.5rem; }
.solution-card {
  background: var(--color-surface);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow);
  overflow: visible;
}
.solution-card h3 { font-size: 1.35rem; margin: 0 0 0.25rem; color: var(--color-text); }
.solution-sub { font-size: 0.9rem; color: var(--color-accent); margin: 0 0 1rem; font-weight: 500; }
.solution-card > p { margin: 0 0 1.25rem; color: var(--color-text-muted); }
.solution-visual {
  padding: 1.25rem 1.5rem;
  background: var(--color-accent-light);
  border-radius: var(--radius);
  font-size: 0.9rem;
  color: var(--color-text);
  text-align: center;
  border: 1px solid rgba(13, 148, 136, 0.2);
}
.solution-visual--svg {
  padding: 1rem;
  overflow: auto;
  max-height: 420px;
  -webkit-overflow-scrolling: touch;
}
.solution-visual--svg::-webkit-scrollbar { width: 8px; height: 8px; }
.solution-visual--svg::-webkit-scrollbar-thumb { background: #94a3b8; border-radius: 4px; }
.solution-visual--svg::-webkit-scrollbar-track { background: #f1f5f9; border-radius: 4px; }
.solution-visual--svg .flowchart { max-width: 100%; height: auto; display: block; margin: 0 auto; min-height: 160px; }
.solution-visual--tyre .flowchart { max-width: 100%; }
.solution-pathways { display: flex; flex-direction: column; gap: 1.25rem; }
.pathway {
  padding: 1rem 1.25rem;
  background: var(--color-bg);
  border-radius: var(--radius);
  border-left: 3px solid var(--color-accent);
  overflow: visible;
  min-width: 0;
}
.pathway h4 { font-size: 1rem; margin: 0 0 0.35rem; }
.pathway p { margin: 0; font-size: 0.95rem; color: var(--color-text-muted); word-wrap: break-word; }

/* Feedstocks */
.feedstocks { background: var(--color-bg); }
.feedstock-scroll-wrap {
  position: relative;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.scroll-btn {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--color-text-muted);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 1.5rem;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), color var(--transition);
}
.scroll-btn:hover { background: var(--color-accent); color: #fff; border-color: var(--color-accent); }
@media (min-width: 768px) { .scroll-btn { display: flex; } }
.feedstock-cards {
  display: flex;
  gap: 1rem;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding: 0.5rem 0;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}
.feedstock-cards::-webkit-scrollbar { height: 6px; }
.feedstock-cards::-webkit-scrollbar-thumb { background: var(--color-accent); border-radius: 3px; }
.feedstock-card {
  flex: 0 0 280px;
  scroll-snap-align: start;
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid rgba(0,0,0,0.04);
}
.feedstock-card[data-category="rubber"] .feedstock-cat { color: #0d9488; }
.feedstock-card[data-category="plastic"] .feedstock-cat { color: #0369a1; }
.feedstock-card[data-category="other"] .feedstock-cat { color: #6b7280; }
.feedstock-cat {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  display: block;
  margin-bottom: 0.5rem;
}
.feedstock-card h4 { font-size: 1rem; margin: 0 0 0.25rem; }
.feedstock-card p { margin: 0; font-size: 0.9rem; color: var(--color-text-muted); }

/* Services */
.services ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 1.5rem; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); }
.service-item {
  background: var(--color-surface);
  padding: 1.75rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: transform var(--transition);
}
.service-item:hover { transform: translateY(-2px); }
.service-icon {
  display: inline-block;
  width: 40px;
  height: 40px;
  line-height: 40px;
  text-align: center;
  background: var(--color-accent-light);
  color: var(--color-accent);
  border-radius: var(--radius);
  font-size: 1.25rem;
  margin-bottom: 1rem;
}
.service-item h4 { font-size: 1.05rem; margin: 0 0 0.35rem; }
.service-item p { margin: 0; font-size: 0.95rem; color: var(--color-text-muted); }

/* Network */
.network-map {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
}
.network-node {
  background: var(--color-surface);
  padding: 1.75rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border-top: 3px solid var(--color-accent);
}
.network-node h4 { font-size: 1.1rem; margin: 0 0 0.5rem; color: var(--color-accent); }
.network-node p { margin: 0; font-size: 0.95rem; color: var(--color-text-muted); }

/* About */
.about-content { max-width: 720px; }
.about-text { font-size: 1.05rem; color: var(--color-text-muted); margin: 0 0 1rem; line-height: 1.75; }
.about-badges { font-size: 0.9rem; color: var(--color-text-muted); margin: 0; }

/* Contact */
.contact-grid {
  display: grid;
  gap: 2rem;
  grid-template-columns: 1fr;
}
@media (min-width: 720px) {
  .contact-grid { grid-template-columns: 1fr 1fr; align-items: start; }
}
.contact-info {
  font-size: 0.95rem;
  color: var(--color-text-muted);
}
.contact-info p { margin: 0 0 0.6rem; }
.contact-company { font-weight: 600; color: var(--color-text); }
.contact-info a {
  color: var(--color-accent);
  text-decoration: none;
}
.contact-info a:hover { text-decoration: underline; }
.contact-form {
  max-width: 100%;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}
@media (min-width: 720px) { .contact-form { max-width: 480px; } }
.form-row label { display: block; font-weight: 500; margin-bottom: 0.35rem; font-size: 0.95rem; }
.form-row input,
.form-row textarea {
  width: 100%;
  padding: 0.65rem 0.9rem;
  font-family: inherit;
  font-size: 1rem;
  border: 1px solid #cbd5e1;
  border-radius: var(--radius);
  background: var(--color-surface);
}
.form-row input:focus,
.form-row textarea:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.15);
}
.form-row input::placeholder,
.form-row textarea::placeholder { color: #94a3b8; }
.form-status { margin: 0 0 0.5rem; font-size: 0.95rem; min-height: 1.4em; }
.form-status:empty { display: none; }

/* Footer */
.footer {
  background: var(--color-nav-bg);
  color: var(--color-nav-text);
  padding: 1.5rem 1.5rem;
  text-align: center;
}
.footer-brand { font-weight: 600; margin: 0 0 0.35rem; }
.footer-legal { font-size: 0.85rem; opacity: 0.9; margin: 0 0 0.25rem; }
.footer-address { font-size: 0.85rem; opacity: 0.9; margin: 0 0 0.25rem; }
.footer-contact { font-size: 0.9rem; margin: 0; }
.footer-contact a { color: var(--color-nav-text); text-decoration: none; }
.footer-contact a:hover { text-decoration: underline; }