/* =========================================================
   球云体育 · AI 落地页 (白底正式·极简版)
   品牌色:
     primary       #D7263D
     primary-dark  #A81C2E
     primary-soft  #FDECEE
   ========================================================= */

:root {
  --c-primary:        #D7263D;
  --c-primary-dark:   #A81C2E;
  --c-primary-soft:   #FDECEE;

  --c-bg:             #FFFFFF;
  --c-surface:        #F7F8FA;
  --c-line:           #E6E8EC;
  --c-line-strong:    #D5D9DF;

  --c-ink:            #14161A;
  --c-ink-2:          #4B5159;
  --c-ink-3:          #8A8F98;
  --c-ink-4:          #B7BCC4;

  --shadow-card:      0 1px 2px rgba(20,22,26,.04), 0 6px 18px -6px rgba(20,22,26,.08);
  --shadow-cta:       0 6px 16px -4px rgba(215,38,61,.32);

  --max-w: 1120px;
  --pad-x: clamp(20px, 4vw, 40px);
}

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;
  font-weight: 400;
  line-height: 1.6;
  color: var(--c-ink);
  background: var(--c-bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; -webkit-tap-highlight-color: transparent; }
button { font: inherit; cursor: pointer; border: 0; background: none; color: inherit; }
em { font-style: normal; }
ul { list-style: none; }

/* ============== HEADER ============== */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .9);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--c-line);
}
.nav__inner {
  max-width: var(--max-w); margin: 0 auto;
  height: 64px;
  padding: 0 var(--pad-x);
  display: flex; align-items: center; justify-content: space-between;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand__icon { width: 30px; height: 30px; border-radius: 7px; }
.brand__name { font-size: 16px; font-weight: 700; letter-spacing: .2px; color: var(--c-ink); }

.nav__links { display: flex; align-items: center; gap: 36px; }
.nav__links a {
  font-size: 14px; color: var(--c-ink-2); font-weight: 500;
  transition: color .15s;
}
.nav__links a:hover { color: var(--c-primary); }

.nav__cta {
  padding: 9px 18px; border-radius: 8px;
  background: var(--c-primary);
  color: #fff; font-weight: 600; font-size: 14px;
  transition: background .15s, transform .15s;
}
.nav__cta:hover { background: var(--c-primary-dark); transform: translateY(-1px); }

@media (max-width: 720px) {
  .nav__links { display: none; }
  .nav__inner { height: 56px; }
}

/* ============== HERO ============== */
.hero {
  position: relative;
  padding: clamp(64px, 9vw, 120px) var(--pad-x) clamp(56px, 8vw, 96px);
  text-align: center;
}
.hero__inner { max-width: 880px; margin: 0 auto; }

.hero__chip {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px 6px 10px;
  border: 1px solid var(--c-line-strong);
  border-radius: 999px;
  background: #fff;
  font-size: 12px; color: var(--c-ink-2);
  white-space: nowrap;
  box-shadow: 0 1px 2px rgba(20,22,26,.04);
}
.hero__chip em { color: var(--c-primary); font-family: 'Oswald', monospace; font-weight: 700; letter-spacing: .3px; }
.hero__chip .dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--c-primary);
  animation: ping 1.8s infinite;
}
@keyframes ping {
  0%   { box-shadow: 0 0 0 0 rgba(215,38,61,.45); }
  70%  { box-shadow: 0 0 0 8px rgba(215,38,61,0); }
  100% { box-shadow: 0 0 0 0 rgba(215,38,61,0); }
}

.hero__title {
  margin-top: 24px;
  font-weight: 800;
  font-size: clamp(34px, 5.2vw, 60px);
  line-height: 1.18;
  letter-spacing: -.01em;
  color: var(--c-ink);
}
.hero__title .hl { color: var(--c-primary); }

.hero__desc {
  margin: 22px auto 0;
  max-width: 580px;
  font-size: clamp(15px, 1.3vw, 17px);
  color: var(--c-ink-2);
  line-height: 1.75;
}

.hero__cta { margin-top: 32px; display: flex; gap: 12px; flex-wrap: wrap; justify-content: center; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 13px 26px;
  border-radius: 10px;
  font-weight: 600; font-size: 15px;
  transition: background .15s, transform .15s, box-shadow .15s, border-color .15s, color .15s;
}
.btn--primary {
  background: var(--c-primary);
  color: #fff;
  box-shadow: var(--shadow-cta);
}
.btn--primary:hover { background: var(--c-primary-dark); transform: translateY(-1px); box-shadow: 0 10px 22px -4px rgba(215,38,61,.4); }
.btn--ghost {
  color: var(--c-ink);
  border: 1px solid var(--c-line-strong);
  background: #fff;
}
.btn--ghost:hover { border-color: var(--c-primary); color: var(--c-primary); }

/* hero 数据条 */
.hero__meta {
  margin: 56px auto 0;
  max-width: 880px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  padding: 28px 24px;
  border: 1px solid var(--c-line);
  border-radius: 16px;
  background: #fff;
  box-shadow: var(--shadow-card);
}
.hero__meta li { text-align: center; position: relative; }
.hero__meta li + li::before {
  content: ''; position: absolute; left: 0; top: 18%; bottom: 18%; width: 1px;
  background: var(--c-line);
}
.hero__meta .num {
  display: inline-flex; align-items: baseline;
  font-family: 'Oswald', sans-serif;
  font-size: clamp(22px, 2.6vw, 30px);
  font-weight: 600;
  color: var(--c-ink);
  letter-spacing: -.01em;
  line-height: 1;
}
.hero__meta .num em { font-family: inherit; font-weight: 700; color: var(--c-ink); }
.hero__meta li p { margin-top: 8px; font-size: 12px; color: var(--c-ink-3); letter-spacing: .3px; }

@media (max-width: 720px) {
  .hero__meta { grid-template-columns: 1fr 1fr; gap: 20px 0; padding: 22px 18px; }
  .hero__meta li:nth-child(odd)::before { display: none; }
  .hero__meta li:nth-child(3)::before { display: block; top: -10px; left: 50%; right: 50%; bottom: auto; width: auto; height: 1px; transform: translateX(-50%); background: transparent; }
}

/* ============== Section 通用 ============== */
.section {
  position: relative;
  padding: clamp(72px, 9vw, 110px) var(--pad-x);
}
.section--gray { background: var(--c-surface); border-top: 1px solid var(--c-line); border-bottom: 1px solid var(--c-line); }
.section__head { max-width: 680px; margin: 0 auto clamp(36px, 5vw, 56px); text-align: center; }
.section__eyebrow {
  display: inline-block;
  font-family: 'Oswald', monospace;
  font-size: 12px; letter-spacing: 2.4px;
  color: var(--c-primary);
  font-weight: 600;
}
.section__title {
  margin-top: 10px;
  font-size: clamp(26px, 3.6vw, 38px);
  font-weight: 700;
  line-height: 1.3; letter-spacing: -.01em;
  color: var(--c-ink);
}
.section__title .hl { color: var(--c-primary); }
.section__sub { margin: 14px auto 0; max-width: 580px; color: var(--c-ink-2); font-size: clamp(14px, 1.2vw, 16px); line-height: 1.75; }

/* ============== Cards 通用 ============== */
.cards {
  max-width: var(--max-w);
  margin: 0 auto;
  display: grid;
  gap: 16px;
}
.cards--3 { grid-template-columns: repeat(3, 1fr); }
.cards--4 { grid-template-columns: repeat(4, 1fr); }

.card {
  position: relative;
  padding: 30px 26px;
  border-radius: 14px;
  background: #fff;
  border: 1px solid var(--c-line);
  transition: transform .25s, border-color .2s, box-shadow .25s;
}
.card:hover { transform: translateY(-3px); border-color: var(--c-line-strong); box-shadow: var(--shadow-card); }

.card__num {
  font-family: 'Oswald', sans-serif;
  font-size: 13px; font-weight: 600;
  color: var(--c-primary);
  letter-spacing: 3px;
}
.card__title { margin-top: 12px; font-size: 18px; font-weight: 700; color: var(--c-ink); letter-spacing: -.01em; }
.card__desc { margin-top: 10px; font-size: 14px; color: var(--c-ink-2); line-height: 1.75; }
.card__desc strong { color: var(--c-primary); font-weight: 700; }

/* feature 卡 */
.card--feat { padding: 26px 22px; }
.card__ico {
  width: 40px; height: 40px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  background: var(--c-primary-soft);
  color: var(--c-primary);
  margin-bottom: 14px;
}
.card__ico svg { width: 20px; height: 20px; }
.card--feat h4 { font-size: 16px; font-weight: 700; color: var(--c-ink); margin-bottom: 6px; }
.card--feat p { font-size: 13px; color: var(--c-ink-2); line-height: 1.7; }

@media (max-width: 900px) {
  .cards--3 { grid-template-columns: 1fr; }
  .cards--4 { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 520px) {
  .cards--4 { grid-template-columns: 1fr; }
}

/* ============== Download ============== */
.download {
  padding: clamp(64px, 8vw, 100px) var(--pad-x);
}
.download__inner {
  max-width: 760px;
  margin: 0 auto;
  text-align: center;
  padding: clamp(40px, 6vw, 64px) clamp(28px, 5vw, 48px);
  border-radius: 20px;
  background: #fff;
  border: 1px solid var(--c-line);
  box-shadow: var(--shadow-card);
}
.download__title {
  margin-top: 10px;
  font-size: clamp(24px, 3.2vw, 36px);
  font-weight: 700; line-height: 1.3; letter-spacing: -.01em;
  color: var(--c-ink);
}
.download__title .hl { color: var(--c-primary); }
.download__desc { margin-top: 12px; color: var(--c-ink-2); font-size: 15px; }

.download__btns { margin-top: 28px; display: flex; gap: 12px; flex-wrap: wrap; justify-content: center; }
.dl-btn {
  display: inline-flex; align-items: center; gap: 12px;
  padding: 12px 22px;
  border-radius: 10px;
  background: #fff;
  border: 1px solid var(--c-line-strong);
  color: var(--c-ink);
  transition: background .15s, border-color .15s, transform .15s;
  min-width: 180px;
}
.dl-btn:hover { border-color: var(--c-primary); transform: translateY(-1px); }
.dl-btn--ios.dl-btn--active, .dl-btn--android.dl-btn--active { background: var(--c-primary); border-color: transparent; box-shadow: var(--shadow-cta); color: #fff; }
.dl-btn__icon { width: 26px; height: 26px; flex-shrink: 0; }
.dl-btn span { display: flex; flex-direction: column; line-height: 1.2; text-align: left; }
.dl-btn small { font-size: 11px; color: var(--c-ink-3); letter-spacing: .3px; }
.dl-btn strong { font-size: 15px; font-weight: 700; margin-top: 2px; }
.dl-btn--active small { color: rgba(255,255,255,.78); }
.dl-btn--active strong { color: #fff; }

.download__hint {
  margin-top: 22px;
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 12px; color: var(--c-ink-3);
}
.hint-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--c-primary); animation: ping 1.8s infinite; }

/* ============== Footer ============== */
.footer {
  border-top: 1px solid var(--c-line);
  padding: 32px var(--pad-x);
  background: #fff;
}
.footer__inner {
  max-width: var(--max-w); margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  gap: 24px; flex-wrap: wrap;
}
.footer__brand { display: flex; align-items: center; gap: 10px; }
.footer__brand img { width: 28px; height: 28px; border-radius: 6px; }
.footer__brand span { font-size: 14px; font-weight: 600; color: var(--c-ink); }

.footer__links { display: flex; gap: 26px; }
.footer__links a { font-size: 13px; color: var(--c-ink-2); transition: color .15s; }
.footer__links a:hover { color: var(--c-primary); }

.footer__copy {
  font-size: 12px; color: var(--c-ink-3); line-height: 1.7;
  display: flex; flex-direction: column; align-items: flex-end;
}
.footer__copy small { color: var(--c-ink-4); margin-top: 2px; }

@media (max-width: 720px) {
  .footer__inner { flex-direction: column; align-items: flex-start; }
  .footer__copy { align-items: flex-start; }
}

/* ============== Reveal Animation ============== */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .6s cubic-bezier(.2,.8,.2,1), transform .6s cubic-bezier(.2,.8,.2,1); }
.reveal.is-in { opacity: 1; transform: none; }
.reveal-d1 { transition-delay: .06s; }
.reveal-d2 { transition-delay: .12s; }
.reveal-d3 { transition-delay: .18s; }
.reveal-d4 { transition-delay: .24s; }

/* 减少动效偏好 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
}