/* ==========================================================================
   Soter-X 公司官网 —— 全局样式（大型咨询公司风格）
   参考：麦肯锡 / BCG / 德勤 等大型咨询公司的官网版式
   视觉：白底为主 + 深藏青强调 + 金色点缀，图文混排，严谨排版
   ========================================================================== */

:root {
  --navy-900: #0f1a30;
  --navy-800: #16263f;
  --navy-700: #1f3557;
  --navy-600: #2a4570;
  --navy-500: #3a5a8f;
  --navy-100: #e8edf5;
  --navy-50: #f3f6fa;

  --gold-500: #c9a227;
  --gold-600: #ad8a1f;
  --gold-400: #d9b64a;
  --gold-50: #faf5e6;

  --bg: #ffffff;
  --surface: #ffffff;
  --bg-soft: #f6f8fb;
  --border: #e6eaf0;
  --border-strong: #d5dce6;
  --text: #1c2530;
  --text-secondary: #4a5563;
  --text-muted: #7a8595;

  --shadow-sm: 0 1px 3px rgba(15, 26, 48, 0.06);
  --shadow-md: 0 8px 24px rgba(15, 26, 48, 0.08);
  --shadow-lg: 0 20px 48px rgba(15, 26, 48, 0.12);

  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; }

body {
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--navy-600); text-decoration: none; }
a:hover { color: var(--gold-600); }

img, svg { display: inline-block; vertical-align: middle; }
::selection { background: rgba(201, 162, 39, 0.25); }
:focus-visible { outline: 2px solid var(--gold-500); outline-offset: 2px; }

.container { width: 100%; max-width: 1180px; margin: 0 auto; padding: 0 28px; }

/* ---------- 顶部导航（白底细窄） ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #fff;
  border-bottom: 1px solid var(--border);
  transition: box-shadow 0.25s ease;
}
.site-header.scrolled { box-shadow: 0 2px 14px rgba(15, 26, 48, 0.08); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px 32px;
  padding-top: 17px;
  padding-bottom: 17px;
}

.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--navy-900); }
.brand:hover { color: var(--navy-900); }
.brand-mark { font-size: 24px; font-weight: 800; letter-spacing: 0.5px; line-height: 1; color: var(--navy-900); }
.brand-mark .dot { color: var(--gold-500); }
.brand-mark .brand-x { color: var(--gold-500); }
.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.brand-name { font-size: 17px; font-weight: 700; color: var(--navy-900); letter-spacing: 0.3px; }
.brand-sub { font-size: 12px; color: var(--text-muted); letter-spacing: 2px; }

.main-nav { display: flex; align-items: center; gap: 8px; }

.nav-link {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  padding: 8px 18px;
  font-size: 16px;
  line-height: 1.3;
  color: var(--text-secondary);
  font-weight: 500;
  border-radius: 5px;
  transition: color 0.2s ease, background-color 0.2s ease;
}
.nav-en {
  font-size: 10.5px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  opacity: 0.65;
  font-weight: 500;
  line-height: 1.1;
}
.nav-link:hover { color: var(--navy-900); background: var(--bg-soft); }
.nav-link.active { color: var(--navy-800); font-weight: 700; position: relative; }
.nav-link.active .nav-en { opacity: 0.9; }
.nav-link.active::after {
  content: "";
  position: absolute;
  left: 18px; right: 18px; bottom: 4px;
  height: 2px;
  background: var(--gold-500);
}

/* 双语：标题英文副标 */
.title-en {
  display: block;
  font-size: 15px;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-top: 8px;
}
.hero .title-en { color: rgba(255,255,255,0.6); }

/* 双语：卡片/条目标题英文 */
.en-sub {
  display: block;
  font-size: 12.5px;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  margin-top: 3px;
}

/* 双语：描述英文（灰色小字） */
.desc-en {
  font-size: 13.5px;
  color: var(--text-muted);
  line-height: 1.7;
  margin-top: 6px;
}

.nav-cta {
  margin-left: 10px;
  padding: 9px 20px;
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  background: var(--navy-800);
  border-radius: 3px;
  transition: background-color 0.2s ease;
  white-space: nowrap;
}
.nav-cta:hover { background: var(--navy-600); color: #fff; }

.nav-lang {
  margin-left: 16px;
  display: inline-flex;
  align-items: center;
  gap: 3px;
  white-space: nowrap;
}
.lang-option {
  padding: 7px 11px;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: 4px;
  transition: color 0.2s ease, background-color 0.2s ease;
}
.lang-option:hover { color: var(--navy-800); background: var(--bg-soft); }
.lang-option.active { color: var(--navy-800); font-weight: 700; background: var(--gold-50); }
.lang-sep { color: var(--border-strong); font-weight: 400; }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  background: var(--navy-900);
  color: #fff;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 80% at 85% 20%, rgba(201, 162, 39, 0.16), transparent 60%),
    radial-gradient(ellipse 50% 70% at 10% 90%, rgba(58, 90, 143, 0.35), transparent 65%),
    linear-gradient(150deg, #12203a 0%, #0f1a30 60%, #1a2c4a 100%);
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: linear-gradient(180deg, rgba(0,0,0,0.6), transparent 90%);
  -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,0.6), transparent 90%);
}
.hero-inner {
  position: relative;
  z-index: 1;
  padding: 112px 0 120px;
  max-width: 860px;
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 12.5px;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--gold-400);
  margin-bottom: 26px;
}
.hero-eyebrow::before {
  content: "";
  width: 34px;
  height: 1px;
  background: var(--gold-500);
}

.hero-title {
  font-size: clamp(34px, 5.4vw, 56px);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: 0.5px;
  color: #fff;
  margin-bottom: 26px;
}

.hero-sub {
  font-size: 18px;
  line-height: 1.85;
  color: rgba(255, 255, 255, 0.78);
  max-width: 680px;
  margin-bottom: 40px;
}

.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  border-radius: 3px;
  transition: transform 0.15s ease, background-color 0.2s ease, color 0.2s ease;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--gold-500); color: #fff; }
.btn-primary:hover { background: var(--gold-600); color: #fff; }
.btn-light { background: #fff; color: var(--navy-900); }
.btn-light:hover { background: var(--navy-100); color: var(--navy-900); }
.btn-outline { background: transparent; color: #fff; border: 1px solid rgba(255,255,255,0.4); }
.btn-outline:hover { background: rgba(255,255,255,0.08); color: #fff; }

/* ---------- 区块 ---------- */
.section { padding: 88px 0; }
.section-soft { background: var(--bg-soft); }

.section-head { max-width: 720px; margin-bottom: 52px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }

.section-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 12.5px;
  letter-spacing: 2.5px;
  text-transform: uppercase;
  color: var(--gold-600);
  margin-bottom: 14px;
}
.section-head.center .section-eyebrow { justify-content: center; }

.section-title {
  font-size: clamp(26px, 3.6vw, 38px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: 0.3px;
  color: var(--navy-900);
  margin-bottom: 18px;
}
.section-desc { font-size: 16.5px; line-height: 1.8; color: var(--text-secondary); }

/* ---------- 图文混排 ---------- */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
}
.split .visual {
  position: relative;
  border-radius: 6px;
  overflow: hidden;
  min-height: 300px;
  background: linear-gradient(150deg, var(--navy-800), var(--navy-600));
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
}
.split .visual .big-num {
  font-size: 96px;
  font-weight: 800;
  color: rgba(255,255,255,0.12);
  letter-spacing: -2px;
}

/* ---------- 卡片网格 ---------- */
.grid { display: grid; gap: 24px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 32px 28px;
  transition: box-shadow 0.2s ease, border-color 0.2s ease;
}
.card:hover { box-shadow: var(--shadow-md); border-color: var(--border-strong); }

.card-icon {
  width: 58px;
  height: 58px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 22px;
}
.card-icon svg { width: 32px; height: 32px; }

/* 三类服务图标的专属配色 */
.card-icon.icon-digital { background: var(--navy-50); color: var(--navy-600); }
.card-icon.icon-tech { background: #fdf3e3; color: #d18a1f; }
.card-icon.icon-ai { background: var(--gold-50); color: var(--gold-600); }

/* 服务卡片内容居中 */
.card-center { text-align: center; }

.card-title { font-size: 17px; font-weight: 700; color: var(--navy-900); margin-bottom: 10px; }
.card-desc { font-size: 14.5px; line-height: 1.75; color: var(--text-secondary); }

/* ---------- 数字统计条 ---------- */
.stats-band { background: var(--navy-900); color: #fff; padding: 64px 0; }
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px; }
.stat { text-align: left; }
.stat-num { font-size: 44px; font-weight: 800; line-height: 1.1; color: #fff; }
.stat-num .unit { font-size: 20px; color: var(--gold-400); }
.stat-label { font-size: 15px; font-weight: 600; color: rgba(255,255,255,0.9); margin-top: 10px; }
.stat-note { font-size: 13px; color: rgba(255,255,255,0.5); margin-top: 5px; }

/* ---------- 列表条目 ---------- */
.item-list { border-top: 1px solid var(--border); }
.item {
  display: flex;
  gap: 24px;
  padding: 26px 4px;
  border-bottom: 1px solid var(--border);
}
.item-num {
  flex: 0 0 auto;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--navy-50);
  color: var(--navy-600);
  font-weight: 700;
  font-size: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.item-title { font-size: 16.5px; font-weight: 700; color: var(--navy-900); margin-bottom: 6px; }
.item-desc { font-size: 14.5px; line-height: 1.75; color: var(--text-secondary); }

/* ---------- 页头（内页横幅） ---------- */
.page-banner {
  position: relative;
  overflow: hidden;
  background: var(--navy-900);
  color: #fff;
  padding: 72px 0;
}
.page-banner .container { position: relative; z-index: 1; }
.page-banner .eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 12.5px;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--gold-400);
  margin-bottom: 16px;
}
.page-banner .eyebrow::before { content: ""; width: 34px; height: 1px; background: var(--gold-500); }
.page-banner h1 { font-size: clamp(30px, 4.4vw, 44px); font-weight: 800; letter-spacing: 0.5px; line-height: 1.2; }
.page-banner p { margin-top: 16px; font-size: 17px; color: rgba(255,255,255,0.72); max-width: 700px; }

/* ---------- 联系表单 ---------- */
.contact-form .field { margin-bottom: 20px; }
.contact-form label { display: block; font-size: 14px; font-weight: 600; color: var(--navy-900); margin-bottom: 8px; }
.contact-form input,
.contact-form textarea {
  width: 100%;
  padding: 13px 15px;
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  font-family: inherit;
  font-size: 15px;
  color: var(--text);
  background: #fff;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--gold-500);
  box-shadow: 0 0 0 3px rgba(201, 162, 39, 0.14);
}
.contact-form textarea { resize: vertical; min-height: 140px; }

.contact-info .row { display: flex; gap: 16px; align-items: flex-start; padding: 18px 0; border-bottom: 1px solid var(--border); }
.contact-info .row:first-child { border-top: 1px solid var(--border); }
.contact-info .label { font-size: 14px; font-weight: 700; color: var(--navy-900); min-width: 76px; }
.contact-info .val { font-size: 15px; color: var(--text-secondary); word-break: break-all; }

/* ---------- 案例标签 ---------- */
.case-tag {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 1px;
  color: var(--gold-600);
  background: var(--gold-50);
  border-radius: 3px;
  padding: 3px 11px;
  margin-bottom: 16px;
}
.case-meta { font-size: 13px; color: var(--text-muted); margin-top: 16px; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--navy-900); color: rgba(255,255,255,0.62); padding: 72px 0 32px; margin-top: auto; }
.footer-inner { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 48px; }
.footer-brand .brand-name { color: #fff; font-size: 20px; font-weight: 800; letter-spacing: 0.5px; }
.footer-brand p { margin-top: 16px; font-size: 14px; max-width: 320px; line-height: 1.8; color: rgba(255,255,255,0.55); }
.footer-col h4 { color: #fff; font-size: 13px; font-weight: 700; margin-bottom: 18px; letter-spacing: 1.5px; text-transform: uppercase; }
.footer-col a { display: block; color: rgba(255,255,255,0.6); font-size: 14px; margin-bottom: 12px; }
.footer-col a:hover { color: var(--gold-400); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  margin-top: 56px;
  padding-top: 24px;
  font-size: 13px;
  color: rgba(255,255,255,0.42);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}
.footer-bottom span:first-child {
  flex: 1;
  text-align: center;
}

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .grid-3, .grid-2, .grid-4 { grid-template-columns: 1fr 1fr; }
  .split { grid-template-columns: 1fr; gap: 32px; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .grid-3, .grid-2, .grid-4 { grid-template-columns: 1fr; }
  .stats { grid-template-columns: 1fr 1fr; gap: 20px; }
  .hero-inner { padding: 72px 0 80px; }
  .section { padding: 60px 0; }
  .nav-cta { display: none; }
  /* 手机端导航：第一行品牌+语言切换，第二行导航横排（不换行） */
  .header-inner { flex-wrap: wrap; gap: 2px 16px; padding-top: 13px; padding-bottom: 13px; }
  .brand { gap: 9px; }
  .brand-mark { font-size: 21px; letter-spacing: 0.3px; }
  .brand-name { font-size: 15px; }
  .brand-sub { font-size: 10.5px; letter-spacing: 1.5px; }
  .main-nav {
    flex: 1 1 100%;
    order: 3;
    justify-content: space-between;
    gap: 2px;
    margin-top: 9px;
    padding-top: 10px;
    border-top: 1px solid var(--border);
  }
  .nav-link {
    flex: 1;
    justify-content: center;
    padding: 8px 4px;
    font-size: 14.5px;
    white-space: nowrap;
  }
  .nav-lang { margin-left: 0; }
  .lang-option { padding: 6px 9px; font-size: 13px; }
  /* hero 标题手机端缩小 */
  .hero-title { font-size: 28px; line-height: 1.35; }
  .hero-sub { font-size: 15.5px; }
  /* footer 手机端压缩间距 */
  .footer-inner { grid-template-columns: 1fr; gap: 24px; }
  .footer-col h4 { margin-bottom: 12px; }
  .footer-bottom { margin-top: 32px; padding-top: 18px; }
}
/* 超窄屏（<360px）进一步压缩 */
@media (max-width: 359px) {
  .nav-link { font-size: 13.5px; padding: 7px 2px; }
  .brand-mark { font-size: 19px; }
  .brand-name { font-size: 13.5px; }
  .brand-sub { display: none; }
}


/* ---------- 更新日志 ---------- */
.changelog-list { border-top: 1px solid var(--border); }
.cl-item {
  display: flex;
  gap: 28px;
  padding: 26px 4px;
  border-bottom: 1px solid var(--border);
}
.cl-version {
  flex: 0 0 130px;
  font-weight: 700;
  font-size: 15px;
  color: var(--navy-800);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.cl-date { flex: 0 0 70px; font-size: 13.5px; color: var(--text-muted); padding-top: 2px; }
.cl-body { flex: 1; }
.cl-title { font-size: 15.5px; font-weight: 600; color: var(--navy-900); margin-bottom: 4px; }
.cl-note { font-size: 14px; line-height: 1.7; color: var(--text-secondary); }
.cl-item:first-child .cl-version { color: var(--gold-600); }
.cl-latest-tag {
  display: inline-block;
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--gold-600);
  background: var(--gold-50);
  border-radius: 3px;
  padding: 2px 8px;
  margin-left: 8px;
  vertical-align: 2px;
}
.footer-bottom .footer-version { color: rgba(255,255,255,0.42); transition: color 0.2s ease; }
.footer-bottom .footer-version:hover { color: var(--gold-400); }
@media (max-width: 640px) {
  .cl-item { flex-direction: column; gap: 6px; }
}