/* ==========================================================================
   UCA Theme — 严格对齐 ucentralasia.org 真实设计
   2026-10-13 v1

   真实设计系统 (从 ucentralasia.org 提取):
   - 主色: deep indigo  #263a80 (h2 标题, button hover, 深 navy)
   - 辅色: sky blue     #2d9cdb (button default, icon-bg, 渐变端)
   - 背景: white + 冷调浅蓝灰 #edf2f5 (section--alt)
   - 字体: Noto Sans (无衬线, 兼容 PingFang SC / 微软雅黑)
   - 风格: 学院派, 深靛蓝渐变 hero 强左对齐, 16px 圆角按钮, 大量留白
   ========================================================================== */

:root {
  --uca-primary:        #263a80;
  --uca-primary-dark:   #1c2e6a;
  --uca-accent:         #2d9cdb;
  --uca-ink:            #101010;
  --uca-muted:          #333;
  --uca-bg:             #FFFFFF;
  --uca-bg-alt:         #edf2f5;
  --uca-bg-dark:        #172556;
  --uca-border:         #dce1f0;
  --uca-deep:           #172556;

  --uca-font-heading:   "Noto Sans", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --uca-font-body:      "Noto Sans", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;

  --uca-s-xxs: .25rem; --uca-s-xs: .5rem;  --uca-s-s:  1rem;
  --uca-s-m:  1.5rem; --uca-s-l:  2rem;   --uca-s-xl: 2.5rem;
  --uca-s-xxl: 3rem;  --uca-s-xxxl: 4rem;  --uca-s-xxxxl: 5rem;

  --uca-radius:         16px;
  --uca-radius-pill:    999px;
  --uca-t:              200ms ease;
  --uca-container:      1280px;
}

*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--uca-font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--uca-ink);
  background: var(--uca-bg);
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: var(--uca-primary); text-decoration: none; transition: color var(--uca-t); }
a:hover { color: var(--uca-accent); }

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--uca-s-s);
  font-family: var(--uca-font-heading);
  font-weight: 700;
  line-height: 1.2;
  color: var(--uca-primary);
  letter-spacing: -0.02em;
}
h1 { font-size: clamp(2.25rem, 5vw, 3.75rem); font-weight: 700; }
h2 { font-size: clamp(1.75rem, 3.5vw, 2.75rem); font-weight: 700; }
h3 { font-size: 1.25rem; color: var(--uca-ink); }
p { margin: 0 0 var(--uca-s-s); }

.container { max-width: var(--uca-container); margin: 0 auto; padding: 0 var(--uca-s-m); }
.section { padding: var(--uca-s-xxxl) 0; }
.section--alt { background: var(--uca-bg-alt); }

.section__head { margin-bottom: var(--uca-s-xl); max-width: 720px; }
.section__eyebrow {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--uca-accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--uca-s-s);
}
.section__eyebrow::before {
  content: '';
  display: inline-block;
  width: 32px;
  height: 2px;
  background: var(--uca-accent);
  margin-right: var(--uca-s-s);
  vertical-align: middle;
}
.section__head h2 { margin-bottom: var(--uca-s-s); }
.section__head p { font-size: 1.05rem; color: var(--uca-muted); margin: 0; }

/* ===== Site Header (UCA 真实: 白色 utility + 白色 main) ===== */
.site-header {
  background: var(--uca-bg);
  position: relative;
  z-index: 10;
}
.site-header__utility {
  background: var(--uca-bg-alt);
  border-bottom: 1px solid var(--uca-border);
}
.site-header__utility-inner {
  max-width: var(--uca-container);
  margin: 0 auto;
  padding: var(--uca-s-xs) var(--uca-s-m);
  display: flex;
  justify-content: flex-end;
  gap: var(--uca-s-m);
  font-size: 0.8rem;
}
.site-header__utility a { color: #555; }
.site-header__utility a:hover { color: var(--uca-accent); }

.site-header__main {
  border-bottom: 1px solid var(--uca-border);
}
.site-header__main-inner {
  max-width: var(--uca-container);
  margin: 0 auto;
  padding: var(--uca-s-s) var(--uca-s-m);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--uca-s-m);
}
.site-brand { display: flex; align-items: center; }
.site-brand__img { height: 56px; width: 56px; display: block; }

.site-header__nav {
  display: flex;
  gap: var(--uca-s-l);
  align-items: center;
}
.site-header__nav-item {
  color: var(--uca-ink);
  font-size: 0.95rem;
  font-weight: 500;
  padding: var(--uca-s-xs) 0;
  border-bottom: 2px solid transparent;
  transition: all var(--uca-t);
}
.site-header__nav-item:hover {
  color: var(--uca-primary);
  border-bottom-color: var(--uca-accent);
}

.site-header__action-apply {
  background: var(--uca-accent);
  color: var(--uca-bg);
  padding: var(--uca-s-xs) var(--uca-s-m);
  border-radius: var(--uca-radius);
  font-weight: 700;
  font-size: 0.9rem;
  letter-spacing: 0.08em;
  transition: background var(--uca-t);
}
.site-header__action-apply:hover {
  background: var(--uca-primary);
  color: var(--uca-bg);
}

/* ===== Hero (深靛蓝渐变 + 强左对齐, 无图) ===== */
.home-hero {
  position: relative;
  min-height: 68vh;
  overflow: hidden;
}
.home-hero__bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, var(--uca-primary) 0%, var(--uca-deep) 100%);
  z-index: 0;
}
.home-hero__inner {
  position: relative;
  z-index: 2;
  max-width: var(--uca-container);
  margin: 0 auto;
  padding: var(--uca-s-xxxxl) var(--uca-s-m);
  color: var(--uca-bg);
}
.home-hero__eyebrow {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: var(--uca-s-xxs) var(--uca-s-s);
  background: var(--uca-accent);
  color: var(--uca-bg);
  margin-bottom: var(--uca-s-m);
}
.home-hero__title {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  color: var(--uca-bg);
  margin: 0 0 var(--uca-s-m);
  max-width: 14ch;
  font-weight: 700;
  letter-spacing: -0.02em;
}
.home-hero__sub {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.92);
  max-width: 640px;
  margin-bottom: var(--uca-s-l);
}

/* ===== Buttons (UCA 真实: 16px 圆角矩形 + 大写 + letter-spacing) ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--uca-s-xs);
  padding: var(--uca-s-s) var(--uca-s-l);
  border-radius: var(--uca-radius);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  text-decoration: none;
  transition: all var(--uca-t);
  cursor: pointer;
  border: 1.5px solid transparent;
}
.btn--primary { background: var(--uca-accent); color: var(--uca-bg); }
.btn--primary:hover { background: var(--uca-primary); color: var(--uca-bg); }
.btn--ghost {
  background: transparent;
  color: var(--uca-primary);
  border: 1.5px solid var(--uca-primary);
}
.btn--ghost:hover {
  background: var(--uca-primary);
  color: var(--uca-bg);
}

/* ===== Programas Grid (4 大研究领域) ===== */
.programas-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--uca-s-m);
}
@media (max-width: 900px) { .programas-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 600px) { .programas-grid { grid-template-columns: 1fr; } }

.programa-card {
  display: block;
  background: var(--uca-bg);
  border-radius: var(--uca-radius);
  padding: var(--uca-s-l);
  text-decoration: none;
  transition: all var(--uca-t);
  border: 1px solid var(--uca-border);
}
.programa-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(38,58,128,0.10);
  border-color: var(--uca-accent);
}
.programa-card__head {
  margin-bottom: var(--uca-s-s);
}
.programa-card__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: linear-gradient(180deg, var(--uca-accent) 0%, var(--uca-primary) 100%);
  color: var(--uca-bg);
  border-radius: var(--uca-radius);
  font-weight: 700;
  font-size: 0.85rem;
}
.programa-card h3 {
  font-size: 1.1rem;
  color: var(--uca-ink);
  margin-bottom: var(--uca-s-xs);
}
.programa-card h3 span {
  display: block;
  font-size: 0.9rem;
  color: var(--uca-primary);
  font-weight: 500;
  margin-top: 2px;
}
.programa-card p {
  font-size: 0.9rem;
  color: var(--uca-muted);
  margin: 0;
}

/* ===== Valores (4 个 AKDN 价值 / 丝路学术) ===== */
.valores-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--uca-s-l);
}
@media (max-width: 900px) { .valores-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 600px) { .valores-grid { grid-template-columns: 1fr; } }

.valor {
  text-align: left;
}
.valor__num {
  display: inline-block;
  font-family: var(--uca-font-heading);
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--uca-accent);
  margin-bottom: var(--uca-s-s);
  line-height: 1;
}
.valor h3 {
  font-size: 1.15rem;
  color: var(--uca-primary);
  margin-bottom: var(--uca-s-xs);
}
.valor h3::after {
  content: '';
  display: block;
  width: 12%;
  min-width: 24px;
  height: 2px;
  background: var(--uca-accent);
  margin-top: var(--uca-s-xs);
}
.valor p {
  font-size: 0.9rem;
  color: var(--uca-muted);
  margin: 0;
}

/* ===== Stats Bar (数据速览) ===== */
.stats-bar {
  background: var(--uca-bg-alt);
  padding: var(--uca-s-xl) 0;
  border-top: 1px solid var(--uca-border);
  border-bottom: 1px solid var(--uca-border);
}
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--uca-s-l);
  text-align: center;
}
@media (max-width: 900px) { .stats-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 600px) { .stats-grid { grid-template-columns: 1fr; } }
.stat {
  display: flex;
  flex-direction: column;
  gap: var(--uca-s-xxs);
}
.stat__num {
  font-family: var(--uca-font-heading);
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--uca-primary);
  letter-spacing: -0.02em;
  line-height: 1;
}
.stat__label {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--uca-ink);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.stat__sub {
  font-size: 0.8rem;
  color: var(--uca-muted);
}

/* ===== Sedes (三个校区) ===== */
.sedes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--uca-s-m);
}
@media (max-width: 768px) { .sedes-grid { grid-template-columns: 1fr; } }

.sede {
  background: var(--uca-bg);
  border: 1px solid var(--uca-border);
  border-left: 4px solid var(--uca-accent);
  border-radius: var(--uca-radius);
  padding: var(--uca-s-l);
}
.sede h3 {
  font-size: 1.15rem;
  color: var(--uca-primary);
  margin-bottom: var(--uca-s-s);
}
.sede p {
  font-size: 0.9rem;
  color: var(--uca-muted);
  margin-bottom: var(--uca-s-s);
}
.sede__tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--uca-accent);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ===== CTA 申请 ===== */
.home-cta {
  background: linear-gradient(180deg, var(--uca-primary) 0%, var(--uca-deep) 100%);
  color: var(--uca-bg);
  padding: var(--uca-s-xxxxl) 0;
  text-align: center;
}
.home-cta h2 {
  color: var(--uca-bg);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  margin-bottom: var(--uca-s-s);
}
.home-cta p {
  color: rgba(255,255,255,0.85);
  max-width: 640px;
  margin: 0 auto var(--uca-s-l);
  font-size: 1.05rem;
}
.home-cta__actions {
  display: flex;
  gap: var(--uca-s-s);
  justify-content: center;
  flex-wrap: wrap;
}
.home-cta .btn--primary {
  background: var(--uca-accent);
  color: var(--uca-bg);
}
.home-cta .btn--primary:hover {
  background: var(--uca-bg);
  color: var(--uca-primary);
}
.home-cta .btn--ghost {
  background: transparent;
  color: var(--uca-bg);
  border-color: var(--uca-bg);
}
.home-cta .btn--ghost:hover {
  background: var(--uca-bg);
  color: var(--uca-primary);
}

/* ===== Site Footer (深 navy + 4 列) ===== */
.site-footer {
  background: var(--uca-deep);
  color: rgba(255,255,255,0.7);
  padding: var(--uca-s-xxxxl) 0 var(--uca-s-m);
}
.site-footer__grid {
  max-width: var(--uca-container);
  margin: 0 auto;
  padding: 0 var(--uca-s-m);
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--uca-s-l);
}
@media (max-width: 900px) { .site-footer__grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 600px) { .site-footer__grid { grid-template-columns: 1fr; } }

.site-footer h4 {
  color: var(--uca-bg);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: var(--uca-s-s);
  letter-spacing: 0.04em;
}
.site-footer p {
  font-size: 0.85rem;
  color: rgba(255,255,255,0.6);
  line-height: 1.7;
}
.site-footer a { color: rgba(255,255,255,0.7); }
.site-footer a:hover { color: var(--uca-accent); }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer li { margin-bottom: var(--uca-s-xs); }
.site-footer li a { font-size: 0.9rem; }

.site-footer__bottom {
  max-width: var(--uca-container);
  margin: var(--uca-s-l) auto 0;
  padding: var(--uca-s-m) var(--uca-s-m) 0;
  border-top: 1px solid rgba(255,255,255,0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--uca-s-s);
  font-size: 0.8rem;
  color: rgba(255,255,255,0.5);
}
.site-footer__bottom a { color: rgba(255,255,255,0.6); }
.site-footer__bottom a:hover { color: var(--uca-accent); }