/* ============================================
   海南斯德瑞数字科技有限公司 — Corporate Site
   Prefix: sd-
   ============================================ */

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

/* --- Reset & Base --- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --sd-primary: #00997A;
  --sd-primary-hover: #007D64;
  --sd-secondary: #00C1A2;
  --sd-bg: #FFFFFF;
  --sd-surface: #F4FAF8;
  --sd-muted-bg: #F7F8F8;
  --sd-text: #1A1D21;
  --sd-text-secondary: #3D4247;
  --sd-text-muted: #6E7378;
  --sd-radius: 8px;
  --sd-max-width: 1100px;
  --sd-font-display: 'Noto Serif SC', serif;
  --sd-font-body: 'Inter', sans-serif;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--sd-font-body);
  color: var(--sd-text);
  background: var(--sd-bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--sd-primary); text-decoration: none; transition: color .2s; }
a:hover { color: var(--sd-primary-hover); }

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

/* --- Layout --- */
.sd-container {
  max-width: var(--sd-max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Header --- */
.sd-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid #e8ece9;
}

.sd-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  max-width: var(--sd-max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.sd-logo {
  font-family: var(--sd-font-display);
  font-size: 20px;
  font-weight: 700;
  color: var(--sd-text);
}

.sd-logo span { color: var(--sd-primary); }

.sd-nav { display: flex; gap: 32px; list-style: none; }

.sd-nav a {
  font-size: 14px;
  font-weight: 500;
  color: var(--sd-text-secondary);
  transition: color .2s;
}

.sd-nav a:hover { color: var(--sd-primary); }

.sd-menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  width: 28px;
  height: 28px;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
}

.sd-menu-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--sd-text);
  border-radius: 1px;
  transition: .3s;
}

/* --- Hero --- */
.sd-hero {
  padding: 100px 0 80px;
  background: var(--sd-surface);
}

.sd-hero-inner {
  max-width: var(--sd-max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 60px;
}

.sd-hero-text { flex: 1; }

.sd-hero-text h1 {
  font-family: var(--sd-font-display);
  font-size: 42px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 20px;
  color: var(--sd-text);
}

.sd-hero-text h1 em {
  font-style: normal;
  color: var(--sd-primary);
}

.sd-hero-text p {
  font-size: 17px;
  color: var(--sd-text-secondary);
  line-height: 1.8;
  max-width: 480px;
}

.sd-hero-img {
  flex: 0 0 400px;
}

.sd-hero-img img {
  border-radius: var(--sd-radius);
}

/* --- Section Common --- */
.sd-section {
  padding: 80px 0;
}

.sd-section--tinted {
  background: var(--sd-surface);
}

.sd-section-title {
  font-family: var(--sd-font-display);
  font-size: 30px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
}

.sd-section-sub {
  text-align: center;
  color: var(--sd-text-secondary);
  font-size: 16px;
  margin-bottom: 48px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* --- About --- */
.sd-about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.sd-about-img img { border-radius: var(--sd-radius); }

.sd-about-body h3 {
  font-family: var(--sd-font-display);
  font-size: 22px;
  margin-bottom: 16px;
  color: var(--sd-text);
}

.sd-about-body p {
  color: var(--sd-text-secondary);
  margin-bottom: 12px;
  line-height: 1.8;
}

/* --- Services Cards --- */
.sd-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.sd-card {
  background: var(--sd-bg);
  border: 1px solid #e4ebe8;
  border-radius: var(--sd-radius);
  padding: 36px 28px;
  transition: box-shadow .25s, transform .25s;
}

.sd-card:hover {
  box-shadow: 0 8px 30px rgba(0,153,122,.1);
  transform: translateY(-4px);
}

.sd-card-icon {
  width: 48px;
  height: 48px;
  background: var(--sd-surface);
  border-radius: var(--sd-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  font-size: 22px;
}

.sd-card h3 {
  font-family: var(--sd-font-display);
  font-size: 18px;
  margin-bottom: 12px;
}

.sd-card p {
  font-size: 14px;
  color: var(--sd-text-muted);
  line-height: 1.7;
}

/* --- Timeline --- */
.sd-timeline {
  position: relative;
  max-width: 640px;
  margin: 0 auto;
  padding-left: 32px;
}

.sd-timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--sd-secondary);
}

.sd-timeline-item {
  position: relative;
  margin-bottom: 40px;
}

.sd-timeline-item:last-child { margin-bottom: 0; }

.sd-timeline-dot {
  position: absolute;
  left: -32px;
  top: 4px;
  width: 16px;
  height: 16px;
  background: var(--sd-primary);
  border: 3px solid var(--sd-bg);
  border-radius: 50%;
  box-shadow: 0 0 0 2px var(--sd-secondary);
}

.sd-timeline-year {
  font-family: var(--sd-font-display);
  font-size: 20px;
  font-weight: 700;
  color: var(--sd-primary);
  margin-bottom: 4px;
}

.sd-timeline-desc {
  color: var(--sd-text-secondary);
  font-size: 15px;
}

/* --- Contact --- */
.sd-contact-block {
  text-align: center;
}

.sd-contact-block p {
  color: var(--sd-text-secondary);
  margin-bottom: 8px;
  font-size: 15px;
}

.sd-contact-block a {
  font-weight: 600;
}

/* --- Footer --- */
.sd-footer {
  background: #1A1D21;
  color: #a3a7ab;
  padding: 40px 0;
  font-size: 13px;
}

.sd-footer-inner {
  max-width: var(--sd-max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.sd-footer a { color: #c8cbce; }
.sd-footer a:hover { color: #fff; }

.sd-footer-links { display: flex; gap: 24px; list-style: none; }

/* --- Legal Pages --- */
.sd-legal {
  padding: 48px 0 80px;
}

.sd-legal h1 {
  font-family: var(--sd-font-display);
  font-size: 28px;
  margin-bottom: 8px;
}

.sd-legal .sd-legal-updated {
  color: var(--sd-text-muted);
  font-size: 13px;
  margin-bottom: 32px;
}

.sd-legal h2 {
  font-family: var(--sd-font-display);
  font-size: 20px;
  margin-top: 36px;
  margin-bottom: 12px;
  color: var(--sd-text);
}

.sd-legal p, .sd-legal ul {
  color: var(--sd-text-secondary);
  margin-bottom: 14px;
  line-height: 1.8;
}

.sd-legal ul {
  padding-left: 20px;
}

.sd-legal li {
  margin-bottom: 6px;
}

/* --- Responsive --- */
@media (max-width: 860px) {
  .sd-hero-inner { flex-direction: column; text-align: center; }
  .sd-hero-text p { margin: 0 auto; }
  .sd-hero-img { flex: none; width: 100%; max-width: 360px; }
  .sd-about-grid { grid-template-columns: 1fr; }
  .sd-cards { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .sd-nav { display: none; }
  .sd-nav.sd-nav--open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: #fff;
    padding: 16px 24px;
    border-bottom: 1px solid #e8ece9;
    gap: 16px;
  }
  .sd-menu-toggle { display: flex; }
  .sd-hero-text h1 { font-size: 30px; }
  .sd-section-title { font-size: 24px; }
  .sd-footer-inner { flex-direction: column; text-align: center; }
}