/* ==========================================================================
   星耀国际官网 — style.css
   全球能源AI大模型 / 石油天然气 / 电力新能源 / 储能与能源供需
   原创样式表，无远程依赖，无框架。
   ========================================================================== */

:root {
  /* 色彩系统：暖白 / 能源深蓝 / 电力青 / 新能源绿 / 储能橙 / 石墨灰 */
  --c-bg: #f7f4ec;
  --c-bg-alt: #f0ece0;
  --c-surface: #ffffff;
  --c-navy: #0c2a47;
  --c-navy-2: #123a63;
  --c-navy-3: #1c4d80;
  --c-cyan: #1591a6;
  --c-cyan-soft: #e4f3f5;
  --c-green: #2e8b57;
  --c-green-soft: #e7f3ea;
  --c-orange: #d97f2b;
  --c-orange-soft: #faeee0;
  --c-graphite: #383d42;
  --c-text: #23262a;
  --c-text-soft: #5c6570;
  --c-text-faint: #838d97;
  --c-border: #e2ddcd;
  --c-border-soft: #ece8db;
  --shadow-sm: 0 1px 2px rgba(12, 42, 71, 0.06), 0 1px 1px rgba(12, 42, 71, 0.04);
  --shadow-md: 0 6px 20px rgba(12, 42, 71, 0.08);
  --shadow-lg: 0 16px 40px rgba(12, 42, 71, 0.12);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --maxw: 1180px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Courier New", monospace;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--font-sans);
  line-height: 1.75;
  font-size: 16px;
  overflow-x: hidden;
}
img, svg { max-width: 100%; display: block; }
a { color: var(--c-navy-3); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { color: var(--c-navy); line-height: 1.35; margin: 0 0 .6em; font-weight: 700; }
p { margin: 0 0 1em; }
ul, ol { margin: 0 0 1em; padding-left: 1.4em; }
figure { margin: 0; }
button { font-family: inherit; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }
.visually-hidden {
  position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}
.skip-link {
  position: absolute; left: -999px; top: 0; background: var(--c-navy); color: #fff;
  padding: 10px 16px; z-index: 200; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------------------------------------------------------------------- */
/* Header / Nav */
/* ---------------------------------------------------------------------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(247, 244, 236, 0.94);
  backdrop-filter: saturate(140%) blur(6px);
  border-bottom: 1px solid var(--c-border);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 68px;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-logo { width: 34px; height: 34px; flex-shrink: 0; }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-cn { font-weight: 800; font-size: 18px; color: var(--c-navy); letter-spacing: .5px; }
.brand-en { font-size: 11px; color: var(--c-text-faint); letter-spacing: 1.5px; text-transform: uppercase; }
.brand:hover { text-decoration: none; }

.nav-toggle {
  display: none; width: 40px; height: 40px; border: 1px solid var(--c-border);
  background: var(--c-surface); border-radius: var(--radius-sm); cursor: pointer;
  position: relative;
}
.nav-toggle span, .nav-toggle::before, .nav-toggle::after {
  content: ""; position: absolute; left: 9px; right: 9px; height: 2px; background: var(--c-navy);
}
.nav-toggle span { top: 19px; }
.nav-toggle::before { top: 13px; }
.nav-toggle::after { top: 25px; }

.nav-menu { display: flex; align-items: center; gap: 26px; }
.nav-menu a {
  color: var(--c-graphite); font-size: 15px; font-weight: 600; white-space: nowrap;
  padding: 6px 2px; border-bottom: 2px solid transparent;
}
.nav-menu a:hover, .nav-menu a[aria-current="page"] {
  color: var(--c-navy); text-decoration: none; border-bottom-color: var(--c-cyan);
}

@media (max-width: 900px) {
  .nav-toggle { display: block; }
  .nav-menu {
    position: fixed; inset: 68px 0 0 0; background: var(--c-bg);
    flex-direction: column; align-items: flex-start; gap: 0; padding: 10px 20px 30px;
    transform: translateY(-8px); opacity: 0; pointer-events: none; transition: .18s ease;
    overflow-y: auto; border-top: 1px solid var(--c-border);
  }
  .nav-menu.is-open { transform: translateY(0); opacity: 1; pointer-events: auto; }
  .nav-menu a { width: 100%; padding: 14px 4px; border-bottom: 1px solid var(--c-border-soft); }
}

/* ---------------------------------------------------------------------- */
/* Hero */
/* ---------------------------------------------------------------------- */
.hero {
  background: linear-gradient(160deg, var(--c-navy) 0%, var(--c-navy-2) 55%, var(--c-navy-3) 100%);
  color: #eef3f8; position: relative; overflow: hidden;
}
.hero-inner {
  display: grid; grid-template-columns: 1.1fr .9fr; gap: 40px; align-items: center;
  padding: 64px 0 56px;
}
.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 8px; font-size: 13px; font-weight: 700;
  letter-spacing: 1px; color: #bfe3ea; background: rgba(255,255,255,.08);
  padding: 6px 12px; border-radius: 999px; margin-bottom: 18px;
}
.hero h1 { color: #fff; font-size: 34px; margin-bottom: 18px; }
.hero-lead { color: #cfe0ee; font-size: 16.5px; max-width: 56ch; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 8px; margin: 20px 0 0; }
.hero-tags span {
  font-size: 12.5px; color: #dcecf1; background: rgba(255,255,255,.09);
  border: 1px solid rgba(255,255,255,.16); padding: 4px 10px; border-radius: 999px;
}
.hero-media { border-radius: var(--radius-lg); overflow: hidden; background: rgba(255,255,255,.04); }
.hero-actions { display: flex; gap: 12px; margin-top: 26px; flex-wrap: wrap; }

@media (max-width: 860px) {
  .hero-inner { grid-template-columns: 1fr; padding: 40px 0 34px; }
  .hero h1 { font-size: 27px; }
}

/* ---------------------------------------------------------------------- */
/* Buttons / tags */
/* ---------------------------------------------------------------------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px; padding: 11px 20px;
  border-radius: 999px; font-weight: 700; font-size: 14.5px; cursor: pointer; border: 1px solid transparent;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--c-cyan); color: #fff; }
.btn-primary:hover { background: #117686; }
.btn-ghost { background: transparent; color: #eaf3f6; border-color: rgba(255,255,255,.35); }
.btn-ghost:hover { background: rgba(255,255,255,.08); }
.btn-outline { background: var(--c-surface); color: var(--c-navy); border-color: var(--c-border); }
.btn-outline:hover { border-color: var(--c-navy-3); }

.tag-list { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 1em; }
.tag {
  font-size: 12.5px; font-weight: 700; padding: 4px 10px; border-radius: 999px;
  background: var(--c-cyan-soft); color: var(--c-navy-2); border: 1px solid #d3ecef;
}
.tag.tag-green { background: var(--c-green-soft); color: #1e5f3c; border-color: #d3e9da; }
.tag.tag-orange { background: var(--c-orange-soft); color: #8a531a; border-color: #efdcc0; }

/* ---------------------------------------------------------------------- */
/* Sections */
/* ---------------------------------------------------------------------- */
.section { padding: 58px 0; }
.section-alt { background: var(--c-bg-alt); }
.section-head { max-width: 760px; margin: 0 0 34px; }
.eyebrow {
  display: inline-block; font-size: 12.5px; font-weight: 800; letter-spacing: 1.5px;
  color: var(--c-cyan); text-transform: uppercase; margin-bottom: 10px;
}
.section-title { font-size: 26px; margin-bottom: 10px; }
.section-lead { color: var(--c-text-soft); font-size: 15.5px; }
.breadcrumb { font-size: 13px; color: var(--c-text-faint); padding: 14px 0; }
.breadcrumb a { color: var(--c-text-faint); }
.breadcrumb span[aria-hidden] { margin: 0 6px; }

/* ---------------------------------------------------------------------- */
/* Chain / relationship diagrams (text based fallback rows) */
/* ---------------------------------------------------------------------- */
.chain-figure { background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius-lg); padding: 22px; box-shadow: var(--shadow-sm); }
.chain-figure figcaption { margin-top: 14px; font-size: 13.5px; color: var(--c-text-faint); }

/* ---------------------------------------------------------------------- */
/* Article cards / grid */
/* ---------------------------------------------------------------------- */
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.card-grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 900px) { .card-grid, .card-grid.cols-2 { grid-template-columns: 1fr; } }

.article-card {
  background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius-md);
  overflow: hidden; box-shadow: var(--shadow-sm); display: flex; flex-direction: column; height: 100%;
}
.article-card .card-media { aspect-ratio: 16/9; background: var(--c-bg-alt); border-bottom: 1px solid var(--c-border-soft); }
.article-card .card-body { padding: 18px 20px 22px; display: flex; flex-direction: column; flex: 1; }
.article-card .card-meta { font-size: 12.5px; color: var(--c-text-faint); margin-bottom: 8px; }
.article-card h3 { font-size: 17.5px; margin-bottom: 8px; }
.article-card p { color: var(--c-text-soft); font-size: 14.5px; flex: 1; }
.article-card .card-link { font-size: 13.5px; font-weight: 700; color: var(--c-navy-3); margin-top: 10px; }

/* Featured (homepage 8 major articles) */
.feature-article {
  background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius-lg);
  padding: 30px; box-shadow: var(--shadow-sm); margin-bottom: 26px;
}
.feature-article .fa-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 30px; align-items: start; }
.feature-article .fa-media { border: 1px solid var(--c-border-soft); border-radius: var(--radius-md); overflow: hidden; background: var(--c-bg-alt); padding: 14px; }
.feature-article .fa-num {
  display: inline-flex; align-items: center; justify-content: center; width: 30px; height: 30px;
  border-radius: 999px; background: var(--c-navy); color: #fff; font-weight: 800; font-size: 13.5px; margin-right: 10px;
}
.feature-article .fa-meta { font-size: 12.5px; color: var(--c-text-faint); margin-bottom: 10px; }
.feature-article h2 { font-size: 21px; }
.feature-article .fa-body p { color: var(--c-text-soft); font-size: 15px; }
.feature-article .fa-link { display: inline-block; margin-top: 6px; font-weight: 700; }
@media (max-width: 860px) { .feature-article .fa-grid { grid-template-columns: 1fr; } }

/* 首页文章：展开完整分析 */
.article-expand .fa-more { max-height: 0; overflow: hidden; transition: max-height .25s ease; }
.article-expand[data-open="true"] .fa-more { max-height: 3000px; }
.article-expand .fa-more-inner { padding-top: 6px; }
.article-expand .fa-toggle {
  margin-top: 12px; background: none; border: 1px solid var(--c-border); color: var(--c-navy-3);
  font-weight: 700; font-size: 13.5px; padding: 8px 16px; border-radius: 999px; cursor: pointer;
}
.article-expand .fa-toggle:hover { border-color: var(--c-navy-3); }

/* Full article page layout */
.article-full { padding: 40px 0 20px; }
.article-head { max-width: 760px; margin: 0 auto 26px; text-align: left; }
.article-head h1 { font-size: 27px; }
.article-meta { font-size: 13px; color: var(--c-text-faint); margin-bottom: 14px; }
.article-body { max-width: 760px; margin: 0 auto; font-size: 16px; color: #2b2f34; }
.article-body h2 { font-size: 20px; margin-top: 1.6em; }
.article-body h3 { font-size: 17px; margin-top: 1.3em; }
.article-body figure { margin: 1.6em 0; }
.article-body figure img { width: 100%; border: 1px solid var(--c-border); border-radius: var(--radius-md); background: var(--c-surface); }
.article-body figcaption { font-size: 13.5px; color: var(--c-text-faint); margin-top: 10px; }
.article-body .insight {
  border-left: 3px solid var(--c-orange); background: var(--c-orange-soft); padding: 14px 18px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0; font-size: 15px; color: #5b431f; margin: 1.4em 0;
}
.article-body .callout-blue {
  border-left: 3px solid var(--c-cyan); background: var(--c-cyan-soft); padding: 14px 18px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0; font-size: 15px; color: #12414a; margin: 1.4em 0;
}
.back-link { display: inline-block; margin-bottom: 18px; font-weight: 700; font-size: 14px; }

/* ---------------------------------------------------------------------- */
/* Definition list / glossary blocks */
/* ---------------------------------------------------------------------- */
.gloss-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
@media (max-width: 760px) { .gloss-grid { grid-template-columns: 1fr; } }
.gloss-item {
  background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius-md);
  padding: 16px 18px;
}
.gloss-item dt { font-weight: 800; color: var(--c-navy); font-size: 15px; margin-bottom: 6px; }
.gloss-item dd { margin: 0; color: var(--c-text-soft); font-size: 14px; }

/* ---------------------------------------------------------------------- */
/* Interactive: tabs (MW/MWh switch, scenario forecast) */
/* ---------------------------------------------------------------------- */
.tabs { border: 1px solid var(--c-border); border-radius: var(--radius-lg); background: var(--c-surface); overflow: hidden; box-shadow: var(--shadow-sm); }
.tabs-nav { display: flex; flex-wrap: wrap; border-bottom: 1px solid var(--c-border); background: var(--c-bg-alt); }
.tabs-nav button {
  flex: 1; min-width: 120px; padding: 13px 10px; border: none; background: transparent; cursor: pointer;
  font-weight: 700; font-size: 14px; color: var(--c-text-soft); border-bottom: 2px solid transparent;
}
.tabs-nav button[aria-selected="true"] { color: var(--c-navy); border-bottom-color: var(--c-cyan); background: var(--c-surface); }
.tabs-panels { padding: 22px 24px; }
.tab-panel { display: none; }
.tab-panel.is-active { display: block; }
.tab-panel h4 { margin-top: 0; }
.tab-panel p { color: var(--c-text-soft); }

/* ---------------------------------------------------------------------- */
/* Flow diagram interactive (click node -> highlight description) */
/* ---------------------------------------------------------------------- */
.flow-widget {
  border: 1px solid var(--c-border); border-radius: var(--radius-lg); background: var(--c-surface);
  padding: 22px; box-shadow: var(--shadow-sm);
}
.flow-steps { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 16px; }
.flow-steps button {
  border: 1px solid var(--c-border); background: var(--c-bg-alt); border-radius: 999px; padding: 8px 16px;
  font-size: 13.5px; font-weight: 700; color: var(--c-text-soft); cursor: pointer;
}
.flow-steps button[aria-pressed="true"] { background: var(--c-navy); color: #fff; border-color: var(--c-navy); }
.flow-detail { font-size: 14.5px; color: var(--c-text-soft); background: var(--c-bg-alt); border-radius: var(--radius-md); padding: 14px 16px; }
.flow-detail strong { color: var(--c-navy); }

/* AI assistant demo */
.assistant-demo { border: 1px solid var(--c-border); border-radius: var(--radius-lg); background: var(--c-surface); box-shadow: var(--shadow-sm); overflow: hidden; }
.assistant-demo .ad-head { background: var(--c-navy); color: #fff; padding: 16px 20px; display: flex; align-items: center; gap: 10px; }
.assistant-demo .ad-head svg { width: 22px; height: 22px; }
.assistant-demo .ad-body { padding: 20px; }
.assistant-questions { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
.assistant-questions button {
  border: 1px solid var(--c-border); background: var(--c-bg-alt); border-radius: 999px; padding: 8px 14px;
  font-size: 13px; cursor: pointer; color: var(--c-navy-2); font-weight: 600;
}
.assistant-questions button[aria-pressed="true"] { background: var(--c-cyan); color: #fff; border-color: var(--c-cyan); }
.assistant-answer { background: var(--c-bg-alt); border-radius: var(--radius-md); padding: 16px 18px; font-size: 14.5px; color: var(--c-text); }
.assistant-answer .aa-row { display: flex; gap: 8px; font-size: 12.5px; color: var(--c-text-faint); margin-top: 10px; flex-wrap: wrap; }
.assistant-answer .aa-row span { background: var(--c-surface); border: 1px solid var(--c-border); padding: 3px 9px; border-radius: 999px; }
.assistant-note { font-size: 12.5px; color: var(--c-text-faint); margin-top: 12px; }

/* ---------------------------------------------------------------------- */
/* FAQ */
/* ---------------------------------------------------------------------- */
.faq-list { border-top: 1px solid var(--c-border); }
.faq-item { border-bottom: 1px solid var(--c-border); }
.faq-q {
  width: 100%; text-align: left; background: none; border: none; cursor: pointer;
  padding: 16px 4px; font-size: 15.5px; font-weight: 700; color: var(--c-navy);
  display: flex; justify-content: space-between; align-items: center; gap: 14px;
}
.faq-q .faq-icon { flex-shrink: 0; width: 20px; height: 20px; position: relative; }
.faq-q .faq-icon::before, .faq-q .faq-icon::after {
  content: ""; position: absolute; background: var(--c-navy-3); border-radius: 2px;
}
.faq-q .faq-icon::before { left: 2px; right: 2px; top: 9px; height: 2px; }
.faq-q .faq-icon::after { top: 2px; bottom: 2px; left: 9px; width: 2px; transition: transform .15s; }
.faq-item[data-open="true"] .faq-icon::after { transform: rotate(90deg); opacity: 0; }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .22s ease; }
.faq-a-inner { padding: 0 4px 16px; color: var(--c-text-soft); font-size: 14.5px; }
.faq-item[data-open="true"] .faq-a { max-height: 600px; }

/* ---------------------------------------------------------------------- */
/* Company / about / disclaimer */
/* ---------------------------------------------------------------------- */
.about-grid { display: grid; grid-template-columns: 1.3fr .7fr; gap: 30px; }
@media (max-width: 860px) { .about-grid { grid-template-columns: 1fr; } }
.info-card {
  background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius-md);
  padding: 20px; font-size: 14px; color: var(--c-text-soft);
}
.info-card dl { margin: 0; }
.info-card dt { font-weight: 700; color: var(--c-navy); margin-top: 10px; }
.info-card dt:first-child { margin-top: 0; }
.info-card dd { margin: 2px 0 0; }

.disclaimer-box {
  background: var(--c-bg-alt); border: 1px solid var(--c-border); border-radius: var(--radius-md);
  padding: 18px 20px; font-size: 13.5px; color: var(--c-text-soft); margin-top: 18px;
}
.disclaimer-box strong { color: var(--c-navy); }

/* ---------------------------------------------------------------------- */
/* Footer */
/* ---------------------------------------------------------------------- */
.site-footer { background: var(--c-navy); color: #cddce8; padding: 46px 0 22px; margin-top: 40px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 30px; }
@media (max-width: 860px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 540px) { .footer-grid { grid-template-columns: 1fr; } }
.footer-grid h4 { color: #fff; font-size: 14px; margin-bottom: 14px; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid li { margin-bottom: 8px; }
.footer-grid a { color: #b7c9da; font-size: 13.5px; }
.footer-grid a:hover { color: #fff; }
.footer-brand { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.footer-brand .brand-logo { width: 30px; height: 30px; }
.footer-brand span { font-weight: 800; font-size: 17px; color: #fff; }
.footer-desc { font-size: 13.5px; color: #a9bccf; max-width: 40ch; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.12); margin-top: 34px; padding-top: 18px;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px;
  font-size: 12.5px; color: #93a7ba;
}
.footer-record { min-height: 1.2em; }

/* ---------------------------------------------------------------------- */
/* Back to top */
/* ---------------------------------------------------------------------- */
.back-to-top {
  position: fixed; right: 20px; bottom: 20px; width: 46px; height: 46px; border-radius: 999px;
  background: var(--c-navy); color: #fff; border: none; cursor: pointer; box-shadow: var(--shadow-lg);
  opacity: 0; pointer-events: none; transform: translateY(8px); transition: .2s ease; z-index: 90;
}
.back-to-top.is-visible { opacity: 1; pointer-events: auto; transform: translateY(0); }
.back-to-top svg { width: 18px; height: 18px; margin: 0 auto; }

/* ---------------------------------------------------------------------- */
/* Misc utility */
/* ---------------------------------------------------------------------- */
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 26px; }
@media (max-width: 860px) { .two-col { grid-template-columns: 1fr; } }
.mt-lg { margin-top: 30px; }
.center { text-align: center; }
.section-cta { text-align: center; margin-top: 30px; }
table.data-table { width: 100%; border-collapse: collapse; font-size: 14px; }
table.data-table th, table.data-table td { border: 1px solid var(--c-border); padding: 10px 12px; text-align: left; }
table.data-table th { background: var(--c-bg-alt); color: var(--c-navy); }
.scroll-x { overflow-x: auto; }
.pill-list { display: flex; flex-wrap: wrap; gap: 10px; }
.pill-list .pill {
  background: var(--c-surface); border: 1px solid var(--c-border); border-radius: 999px;
  padding: 8px 16px; font-size: 13.5px; font-weight: 600; color: var(--c-navy-2);
}
.section-title-row { display: flex; justify-content: space-between; align-items: flex-end; gap: 20px; flex-wrap: wrap; }
.link-more { font-size: 13.5px; font-weight: 700; }