/* ============================================================
   Yellow Meets Blue · 黄蓝相遇
   主题：黄河金(yellow) 遇见 海蓝(blue)；黄蓝渐变地平线
   前缀 ymb- 避免冲突
   ============================================================ */
:root{
  --ymb-yellow:#E0A93B;      /* 黄河金 */
  --ymb-yellow-d:#C8860D;
  --ymb-sand:#E9D9A8;        /* 沙 */
  --ymb-blue:#1B6CA8;        /* 海蓝 */
  --ymb-blue-d:#0F4E78;
  --ymb-sea:#2E8BB8;
  --ymb-paper:#FBF7EE;       /* 宣纸 */
  --ymb-ink:#243240;
  --ymb-mist:#F1ECDC;
  --ymb-line:rgba(36,50,64,.14);
  --ymb-shadow:0 12px 34px rgba(36,50,64,.12);
  --ymb-radius:14px;
  --ymb-serif:"Cormorant Garamond","Noto Serif SC",serif;
  --ymb-cn:"Noto Serif SC","Songti SC",serif;
  --ymb-sans:"Noto Sans SC","PingFang SC",sans-serif;
  --ymb-maxw:1120px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:var(--ymb-sans);color:var(--ymb-ink);background:var(--ymb-paper);line-height:1.7;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
h1,h2,h3{margin:0;font-weight:700}

/* 双语 */
.en{display:none}
body.lang-en .zh{display:none}
body.lang-en .en{display:inline}

/* 顶部条 */
.topbar{background:var(--ymb-ink);color:#fff;font-size:13px}
.topbar__inner{max-width:var(--ymb-maxw);margin:0 auto;padding:8px 20px;display:flex;justify-content:space-between;align-items:center;gap:12px}
.topbar__tag{opacity:.85}
.topbar__tag em{font-style:normal;color:var(--ymb-yellow)}
.lang-toggle{background:transparent;border:1px solid rgba(255,255,255,.4);color:#fff;border-radius:20px;padding:4px 14px;cursor:pointer;font-size:13px}
.lang-toggle:hover{background:rgba(255,255,255,.12)}

/* 导航 */
.nav{position:sticky;top:0;z-index:50;background:rgba(251,247,238,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--ymb-line)}
.nav__inner{max-width:var(--ymb-maxw);margin:0 auto;padding:14px 20px;display:flex;align-items:center;justify-content:space-between}
.nav__brand{font-family:var(--ymb-serif);font-weight:700;font-size:24px;letter-spacing:.5px;color:var(--ymb-ink)}
.nav__brand span{color:var(--ymb-yellow-d)}
.nav__menu{display:flex;gap:22px}
.nav__menu a{font-size:15px;opacity:.85;padding:4px 0;position:relative}
.nav__menu a:hover{opacity:1;color:var(--ymb-blue)}
.nav__menu a::after{content:"";position:absolute;left:0;bottom:-2px;width:0;height:2px;background:var(--ymb-yellow-d);transition:.25s}
.nav__menu a:hover::after{width:100%}
.nav__burger{display:none;background:none;border:none;font-size:24px;color:var(--ymb-ink);cursor:pointer}

/* Hero：黄(上)蓝(下) 相遇 */
.hero{position:relative;overflow:hidden;padding:96px 20px 200px;color:#fff}
.hero__sky{position:absolute;inset:0;background:linear-gradient(180deg,#F3D27A 0%,#E7B34E 38%,#caa24a 50%,#3E8FB8 64%,#1B6CA8 100%)}
.hero__inner{position:relative;z-index:2;max-width:var(--ymb-maxw);margin:0 auto;text-align:center}
.hero__eyebrow{letter-spacing:2px;font-size:14px;font-weight:700;color:var(--ymb-ink);opacity:.8;margin:0 0 14px}
.hero__title{font-family:var(--ymb-serif);font-weight:700;font-size:clamp(56px,11vw,128px);line-height:.95;color:#fff;text-shadow:0 4px 24px rgba(15,78,120,.35);margin-bottom:18px}
.hero__sub{font-family:var(--ymb-cn);font-size:clamp(18px,3vw,26px);font-weight:700;margin:0 0 18px;text-shadow:0 2px 12px rgba(15,78,120,.3)}
.hero__lead{max-width:720px;margin:0 auto 28px;font-size:clamp(15px,2vw,18px);color:#fff}
.hero__lead em{font-style:normal;font-weight:700;color:var(--ymb-sand)}
.hero__cta{display:flex;gap:14px;justify-content:center;flex-wrap:wrap}
.hero__horizon{position:absolute;left:0;right:0;bottom:0;height:90px;background:linear-gradient(180deg,rgba(27,108,168,0) 0%,rgba(27,108,168,.0) 40%,var(--ymb-paper) 100%)}

/* 按钮 */
.btn{display:inline-flex;align-items:center;justify-content:center;padding:13px 26px;border-radius:30px;font-weight:700;font-size:15px;cursor:pointer;transition:.2s;border:2px solid transparent}
.btn--solid{background:#fff;color:var(--ymb-blue-d)}
.btn--solid:hover{background:var(--ymb-sand)}
.btn--ghost{border-color:#fff;color:#fff}
.btn--ghost:hover{background:rgba(255,255,255,.15)}

/* 通用 section */
.section{max-width:var(--ymb-maxw);margin:0 auto;padding:80px 20px}
.section--tint{background:var(--ymb-mist);max-width:none}
.section--tint>.section__head,.section--tint>.stills,.section--tint>.journal{max-width:var(--ymb-maxw);margin-left:auto;margin-right:auto}
.section__head{text-align:center;margin-bottom:42px}
.section__kicker{display:inline-block;color:var(--ymb-yellow-d);font-weight:700;letter-spacing:2px;font-size:13px;text-transform:uppercase;margin-bottom:10px}
.section__title{font-family:var(--ymb-cn);font-size:clamp(26px,4vw,40px);color:var(--ymb-ink)}
.section__sub{max-width:680px;margin:14px auto 0;color:#5a5046;font-size:16px}

/* Film */
.film{display:grid;grid-template-columns:1.4fr 1fr;gap:40px;align-items:start}
.film__player{aspect-ratio:16/9;border-radius:var(--ymb-radius);font-size:46px}
.film__meta p{color:#4a4036;font-size:16px;margin:0 0 18px}
.film__facts{list-style:none;margin:0;padding:0;border-top:1px dashed var(--ymb-line);padding-top:16px}
.film__facts li{font-size:14px;color:#5a5046;margin-bottom:12px;padding-left:18px;position:relative}
.film__facts li::before{content:"▸";position:absolute;left:0;color:var(--ymb-yellow-d)}

/* Stills */
.stills{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.stills__item{margin:0}
.stills__item .ph{aspect-ratio:4/3}
.stills figcaption{margin-top:8px;font-size:13px;color:var(--ymb-blue-d);font-weight:600}

/* Science */
.science__bar{height:54px;border-radius:30px;background:linear-gradient(90deg,var(--ymb-yellow) 0%,var(--ymb-yellow-d) 45%,var(--ymb-sea) 55%,var(--ymb-blue) 100%);display:flex;align-items:center;justify-content:space-between;padding:0 20px;color:#fff;font-weight:700;font-size:14px;margin-bottom:22px}
.science__intro{max-width:760px;margin:0 auto 36px;font-size:17px;text-align:center;color:#4a4036}
.science__grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.sci{background:#fff;border:1px solid var(--ymb-line);border-radius:var(--ymb-radius);padding:24px;box-shadow:var(--ymb-shadow)}
.sci h3{font-family:var(--ymb-cn);font-size:20px;color:var(--ymb-blue-d);margin-bottom:10px}
.sci p{margin:0;color:#5a5046;font-size:15px}
.science__note{margin-top:24px;font-size:13px;color:#8a7c6a;text-align:center}

/* Journal */
.journal{list-style:none;margin:0;padding:0;border-left:3px solid var(--ymb-yellow-d);max-width:760px;margin-left:auto;margin-right:auto}
.journal__item{position:relative;padding:0 0 30px 28px}
.journal__item:last-child{padding-bottom:0}
.journal__date{font-family:var(--ymb-serif);font-weight:700;font-size:16px;color:var(--ymb-blue)}
.journal__item::before{content:"";position:absolute;left:-11px;top:4px;width:16px;height:16px;border-radius:50%;background:var(--ymb-yellow-d);border:3px solid var(--ymb-mist)}
.journal__item strong{display:block;font-family:var(--ymb-cn);color:var(--ymb-ink);margin:2px 0 4px;font-size:16px}
.journal__item p{margin:0;color:#5a5046;font-size:15px}

/* Footer */
.footer{background:var(--ymb-ink);color:#fff;padding:40px 20px}
.footer__inner{max-width:var(--ymb-maxw);margin:0 auto;display:flex;justify-content:space-between;flex-wrap:wrap;gap:16px;align-items:center}
.footer__brand{font-family:var(--ymb-serif);font-weight:700;font-size:22px;margin:0 0 6px;color:var(--ymb-yellow)}
.footer__line{margin:0;font-size:13px;opacity:.85}
.footer__line a{color:var(--ymb-sand)}
.footer__copy{font-size:13px;opacity:.6;margin:0}

/* 占位 */
.ph{display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,var(--ymb-mist),#e3d6bd);border:1px dashed var(--ymb-line);border-radius:12px;color:var(--ymb-blue-d);position:relative;overflow:hidden}
.ph span{font-size:30px;opacity:.5}
.ph::after{content:attr(data-label);position:absolute;bottom:8px;left:8px;right:8px;font-size:11px;color:#8a7c6a;background:rgba(255,255,255,.7);padding:3px 6px;border-radius:6px;text-align:center}

/* 响应式 */
@media (max-width:860px){
  .film{grid-template-columns:1fr;gap:24px}
  .stills{grid-template-columns:repeat(2,1fr)}
  .science__grid{grid-template-columns:1fr}
  .nav__menu{position:absolute;top:100%;left:0;right:0;background:var(--ymb-paper);flex-direction:column;gap:0;padding:10px 20px;border-bottom:1px solid var(--ymb-line);display:none}
  .nav__menu.open{display:flex}
  .nav__menu a{padding:12px 0;border-bottom:1px solid var(--ymb-line)}
  .nav__burger{display:block}
}
@media (max-width:520px){
  .stills{grid-template-columns:1fr}
  .hero{padding:70px 18px 160px}
}