:root { --brand: #1589DF; --text: #0f172a; --muted: #475569; --panel: rgba(255,255,255,0.7); --primary: var(--brand); --primary-ghost: rgba(21,137,223,.12); --ai-gradient: linear-gradient(135deg, rgba(93,165,219,1), rgba(127,113,234,1) 50%, rgba(0,208,189,1) 100%); --section-bg: #E9F3FF; }
* { box-sizing: border-box; }
html, body { min-height: 100%; }
body { margin: 0; font-family: ui-sans-serif, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif; background: linear-gradient(180deg, rgba(207, 226, 255, 1), rgba(241.42, 241.42, 247.03, 1) 50%, rgba(241, 241, 247, 1) 100%); color: var(--text); }
.container { max-width: 1080px; margin: 0 auto; padding: 0 24px; }
.site-header { border-bottom: 1px solid rgba(255,255,255,0.7); background: rgba(255, 255, 255, .7); backdrop-filter: saturate(140%) blur(12px); position: sticky; top: 0; z-index: 10; }
.header-wrap { display: flex; align-items: center; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 600; letter-spacing: .2px; }
.logo { width: 32px; height: 32px; border-radius: 8px; box-shadow: 0 2px 8px rgba(21,137,223,0.08); }
.brand-name { font-size: 16px; color: var(--text); }
.hero { padding: 128px 0 40px; text-align: center; }
.hero-wrap h1 { margin: 0; font-size: 40px; line-height: 1.2; }
.subtitle { margin: 14px 0 22px; color: var(--muted); font-size: 16px; }
.cta { display: inline-flex; gap: 12px; }
.cta .btn { height: 52px; padding: 0 24px; border-radius: 12px; font-size: 16px; }
.btn { display: inline-flex; align-items: center; justify-content: center; height: 42px; padding: 0 18px; border-radius: 10px; border: 1px solid rgba(21,137,223,.25); color: var(--text); text-decoration: none; transition: all .15s ease; background: rgba(255,255,255,0.7); backdrop-filter: blur(8px); }
.btn:hover { border-color: rgba(21,137,223,.5); transform: translateY(-1px); box-shadow: 0 8px 20px rgba(21,137,223,0.12); }
.btn.primary { background: var(--primary); border-color: var(--primary); color: white; }
.btn.ai { background: var(--ai-gradient); border-color: transparent; color: #fff; }
.ai-text { display: inline-block; font-weight: 600; background: var(--ai-gradient); -webkit-background-clip: text; background-clip: text; color: transparent; text-decoration: none; }
.features { padding: 24px 0 64px; }
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.card { border: 1px solid rgba(255,255,255,0.6); border-radius: 16px; padding: 20px; background: var(--panel); box-shadow: 0 8px 30px rgba(21,137,223,0.08); }
.card h3 { margin: 0 0 8px 0; font-size: 18px; }
.card p { margin: 0; color: var(--muted); }
.site-footer { border-top: 1px solid rgba(255,255,255,0.7); padding: 18px 0; background: rgba(255,255,255,0.6); backdrop-filter: blur(6px); }
.footer-wrap { display: flex; align-items: center; justify-content: space-between; }
.beian { color: #64748b; text-decoration: none; }
.beian:hover { color: var(--brand); }
@media (max-width: 860px) { .grid { grid-template-columns: 1fr; } .hero-wrap h1 { font-size: 32px; } }

/* 贡献名单墙 */
.wall-section { padding: 96px 0 120px; background: var(--section-bg); }
.wall-title { margin: 0 0 28px; text-align: center; font-size: 28px; color: var(--text); }
.wall-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.plaque { position: relative; border: 1px solid rgba(255,255,255,0.6); border-radius: 16px; padding: 16px; background: var(--panel); cursor: default; box-shadow: 0 6px 24px rgba(21,137,223,0.06); }
.plaque:hover { box-shadow: 0 10px 26px rgba(21,137,223,0.08); }
.plaque .name { font-weight: 600; color: var(--text); }
.plaque .order { color: var(--muted); font-size: 13px; }

/* 模态层 */
.modal[hidden] { display: none; }
.modal { position: fixed; inset: 0; z-index: 50; }
.modal-backdrop { position: absolute; inset: 0; background: rgba(15,23,42,.48); backdrop-filter: blur(10px); }
.modal-card { position: relative; z-index: 1; max-width: 520px; margin: 10vh auto; border-radius: 20px; background: rgba(255,255,255,0.8); border: 1px solid rgba(255,255,255,0.7); box-shadow: 0 20px 60px rgba(21,137,223,0.16); overflow: hidden; }
.modal-card.exporting { background: #ffffff; }
.modal-close { position: absolute; top: 10px; right: 12px; width: 36px; height: 36px; border-radius: 10px; border: 1px solid rgba(21,137,223,.25); background: rgba(255,255,255,.7); color: var(--text); cursor: pointer; }
.modal-content { padding: 24px; text-align: center; }
.badge { display: inline-block; padding: 8px 12px; border-radius: 999px; background: var(--ai-gradient); color: #fff; font-size: 13px; margin-bottom: 12px; }
.modal-content h3 { margin: 8px 0 12px; font-size: 24px; }
.meta { margin: 6px 0; color: var(--muted); }
.modal-actions { margin-top: 16px; display: flex; justify-content: center; }

@media (max-width: 1024px) { .wall-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 600px) { .wall-grid { grid-template-columns: 1fr; } }
/* 产品介绍 */
.product { padding: 10px 0 72px; }
.product-intro { padding: 24px; margin-bottom: 20px; }
.product-title { margin: 0 0 8px; font-size: 28px; color: var(--text); }
.product-sub { margin: 0; color: var(--muted); }
.points-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin: 18px 0 12px; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-top: 8px; }
.chip { display: inline-flex; align-items: center; height: 32px; padding: 0 14px; border-radius: 999px; background: rgba(255,255,255,0.7); border: 1px solid rgba(21,137,223,.25); color: var(--text); }
.note { display: flex; justify-content: center; margin-top: 28px; }

@media (max-width: 860px) { .points-grid { grid-template-columns: 1fr; } }

/* 顶部信件 */
.letter { position: relative; max-width: 760px; margin: 0 auto 24px; overflow: hidden; -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,1) 0%, rgba(0,0,0,1) 75%, rgba(0,0,0,0) 100%); mask-image: linear-gradient(180deg, rgba(0,0,0,1) 0%, rgba(0,0,0,1) 75%, rgba(0,0,0,0) 100%); }
.letter-title { margin: 16px 0; font-size: 22px; }
.letter-content p { margin: 8px 0; color: var(--muted); line-height: 1.7; text-align: left; }
.divider { height: 1px; background: linear-gradient(90deg, rgba(21,137,223,.0), rgba(21,137,223,.25), rgba(21,137,223,.0)); margin: 18px 0; }
.divider.subtle { background: linear-gradient(90deg, rgba(148,163,184,.0), rgba(148,163,184,.35), rgba(148,163,184,.0)); margin: 18px 0; }
.letter { position: relative; overflow: hidden; -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,1) 0%, rgba(0,0,0,1) 75%, rgba(0,0,0,0) 100%); mask-image: linear-gradient(180deg, rgba(0,0,0,1) 0%, rgba(0,0,0,1) 75%, rgba(0,0,0,0) 100%); transition: box-shadow .3s ease, transform 360ms cubic-bezier(0.2,0.7,0,1); will-change: transform; }
.letter.expanded { position: fixed; left: 50%; top: 50%; transform: translate(-50%, -50%); width: min(820px, 92vw); z-index: 60; -webkit-mask-image: none; mask-image: none; box-shadow: 0 30px 80px rgba(21,137,223,0.20); max-height: calc(100vh - 12vh); height: auto; overflow-y: auto; -webkit-overflow-scrolling: touch; overscroll-behavior: contain; }
.letter.expanded .letter-content { max-height: none; overflow: visible; }
.letter.expanded::after { display: none; }
.letter-backdrop { position: fixed; inset: 0; background: rgba(15,23,42,.5); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px); z-index: 50; opacity: 0; transition: opacity .24s ease; }
.letter-backdrop.show { opacity: 1; }
.letter-close { position: absolute; top: 10px; right: 12px; width: 32px; height: 32px; border-radius: 999px; border: 1px solid rgba(21,137,223,.25); background: rgba(255,255,255,.95); color: var(--text); cursor: pointer; display: flex; align-items: center; justify-content: center; box-shadow: 0 6px 14px rgba(21,137,223,0.12); z-index: 2; }
.letter-close:hover { box-shadow: 0 10px 20px rgba(21,137,223,0.16); }
.letter:not(.expanded) .letter-close { display: none !important; }
.letter.expanded .letter-close { display: flex; }

@media (max-width: 600px) {
  .container { padding: 0 16px; }
  .hero { padding: 96px 0 32px; }
  .hero-wrap h1 { font-size: 28px; }
  .subtitle { font-size: 15px; }
  .cta { width: 100%; justify-content: center; }
  .cta .btn { width: 100%; max-width: 360px; height: 48px; border-radius: 12px; font-size: 16px; }
  .letter { max-width: 100%; margin: 0 0 20px; }
  .letter { -webkit-mask-image: none !important; mask-image: none !important; position: relative; overflow: hidden; }
  .letter-content { max-height: 140px; overflow: hidden; }
  .letter::after { content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 60%; pointer-events: none; background: linear-gradient(180deg, rgba(241,241,247,0) 0%, rgba(241,241,247,0.85) 60%, rgba(241,241,247,1) 100%); }
  .letter-title { font-size: 20px; }
  .letter-content p { font-size: 14px; line-height: 1.6; }
  .wall-section { padding: 64px 0 96px; background: var(--section-bg); }
  .plaque { padding: 14px; }
  .modal-card { max-width: 92vw; margin: 8vh auto; }
  .letter.expanded { top: 50%; transform: translate(-50%, -50%); width: 94vw; }
  .letter.expanded { max-height: calc(100vh - 10vh); height: auto; overflow-y: auto; -webkit-overflow-scrolling: touch; overscroll-behavior: contain; }
  .letter-close { width: 28px; height: 28px; }
}