/* ==========================================================================
   特有缘 官网样式
   设计意图:深夜天空 + 时空格子网格 = 产品的两个核心意象(时空、共现)。
   暖金色代表「缘」,青色代表「时空」。中文标题用衬线体,拉开与正文的气质差异。
   零依赖、零构建,可直接由 Nginx 静态托管。
   ========================================================================== */

:root {
  --ink: #0b0e1a;
  --ink-2: #121829;
  --ink-3: #1a2138;
  --line: rgba(255, 255, 255, 0.09);
  --line-strong: rgba(255, 255, 255, 0.16);

  --gold: #e8b761;
  --gold-soft: #f4dcae;
  --jade: #6fd3c7;

  --text: #eceaf4;
  --muted: #a2a2ba;
  --muted-2: #7e7e97;

  --serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "SimSun", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --mono: "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;

  --wrap: 1100px;
  --radius: 14px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--ink);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.75;
  overflow-x: hidden;
}

h1,
h2,
h3 {
  font-family: var(--serif);
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: 0.01em;
}

a {
  color: var(--gold-soft);
  text-decoration: none;
}

a:hover {
  color: var(--gold);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* 键盘可达性:所有可聚焦元素统一焦点环 */
:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  padding: 12px 20px;
  background: var(--gold);
  color: var(--ink);
  font-weight: 600;
}

.skip-link:focus {
  left: 12px;
  top: 12px;
}

.muted {
  color: var(--muted);
}

/* ---------- 背景:星点 + 时空格子 ---------- */
.starfield,
.cellgrid {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}

.starfield {
  background-image:
    radial-gradient(1.5px 1.5px at 12% 18%, rgba(255, 255, 255, 0.55) 50%, transparent 51%),
    radial-gradient(1.5px 1.5px at 78% 12%, rgba(255, 255, 255, 0.4) 50%, transparent 51%),
    radial-gradient(1px 1px at 34% 62%, rgba(255, 255, 255, 0.35) 50%, transparent 51%),
    radial-gradient(1.5px 1.5px at 63% 78%, rgba(232, 183, 97, 0.5) 50%, transparent 51%),
    radial-gradient(1px 1px at 88% 52%, rgba(255, 255, 255, 0.3) 50%, transparent 51%),
    radial-gradient(1px 1px at 22% 88%, rgba(111, 211, 199, 0.4) 50%, transparent 51%),
    radial-gradient(900px 500px at 50% -10%, rgba(232, 183, 97, 0.09), transparent 70%),
    radial-gradient(700px 400px at 90% 20%, rgba(111, 211, 199, 0.06), transparent 70%);
}

/* 500m × 2h 的格子意象 */
.cellgrid {
  background-image:
    linear-gradient(to right, var(--line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line) 1px, transparent 1px);
  background-size: 68px 68px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 20%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 20%, transparent 75%);
  opacity: 0.8;
}

/* ---------- 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(12px);
  background: rgba(11, 14, 26, 0.72);
  border-bottom: 1px solid var(--line);
}

.nav {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
  color: var(--text);
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 10px;
  border: 1px solid rgba(232, 183, 97, 0.45);
  background: linear-gradient(150deg, rgba(232, 183, 97, 0.22), rgba(111, 211, 199, 0.12));
  color: var(--gold-soft);
  font-family: var(--serif);
  font-size: 18px;
}

.brand__name {
  font-family: var(--serif);
  font-size: 20px;
  letter-spacing: 0.08em;
}

.nav__links {
  display: flex;
  gap: 26px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 15px;
}

.nav__links a {
  color: var(--muted);
}

.nav__links a:hover {
  color: var(--gold-soft);
  text-decoration: none;
}

/* ---------- 通用区块 ---------- */
main {
  position: relative;
  z-index: 1;
}

.section {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 96px 24px;
  border-top: 1px solid var(--line);
}

.section--narrow {
  max-width: 760px;
}

.section__title {
  font-size: clamp(26px, 4vw, 38px);
  margin: 0 0 14px;
}

.section__sub {
  color: var(--muted);
  margin: 0 0 44px;
  max-width: 62ch;
}

.prose p {
  margin: 0 0 18px;
}

.prose strong {
  color: var(--gold-soft);
  font-weight: 600;
}

.prose--center {
  max-width: 66ch;
  margin: 40px auto 0;
  text-align: center;
  color: var(--muted);
}

/* ---------- Hero ---------- */
.hero {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 110px 24px 96px;
  text-align: center;
}

.hero__eyebrow {
  display: inline-block;
  margin: 0 0 28px;
  padding: 6px 16px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  color: var(--jade);
  font-size: 13px;
  letter-spacing: 0.16em;
}

.hero__title {
  font-size: clamp(34px, 7vw, 68px);
  margin: 0 0 26px;
  letter-spacing: 0.02em;
}

.hero__title em {
  font-style: normal;
  background: linear-gradient(100deg, var(--gold), var(--gold-soft) 45%, var(--jade));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero__lede {
  max-width: 56ch;
  margin: 0 auto 38px;
  color: var(--muted);
  font-size: clamp(16px, 2vw, 19px);
}

.hero__actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 13px 30px;
  border-radius: 999px;
  font-size: 16px;
  border: 1px solid transparent;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-2px);
}

.btn--primary {
  background: linear-gradient(135deg, var(--gold), #d99f45);
  color: #1a1206;
  font-weight: 600;
  box-shadow: 0 10px 30px rgba(232, 183, 97, 0.22);
}

.btn--primary:hover {
  color: #1a1206;
  box-shadow: 0 14px 38px rgba(232, 183, 97, 0.32);
}

.btn--ghost {
  border-color: var(--line-strong);
  color: var(--text);
}

.btn--ghost:hover {
  border-color: var(--gold);
  color: var(--gold-soft);
}

.hero__note {
  margin: 30px 0 0;
  color: var(--muted-2);
  font-size: 14px;
  letter-spacing: 0.08em;
}

/* ---------- 三步 ---------- */
.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}

.step {
  padding: 30px 26px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--ink-2), rgba(18, 24, 41, 0.4));
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.step:hover {
  border-color: rgba(232, 183, 97, 0.32);
  transform: translateY(-3px);
}

.step__num {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--gold);
  letter-spacing: 0.2em;
  margin-bottom: 14px;
}

.step__title {
  font-size: 20px;
  margin: 0 0 12px;
}

.step p {
  margin: 0;
  color: var(--muted);
  font-size: 15.5px;
}

.step strong {
  color: var(--gold-soft);
}

/* ---------- 公式 ---------- */
.formula {
  margin: 0 0 44px;
  padding: 26px 28px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--gold);
  border-radius: var(--radius);
  background: var(--ink-2);
}

.formula pre {
  margin: 0 0 18px;
  overflow-x: auto;
}

.formula code {
  font-family: var(--mono);
  font-size: 14.5px;
  color: var(--jade);
  line-height: 1.9;
  white-space: pre;
}

.formula figcaption {
  color: var(--muted);
  font-size: 15px;
  margin: 0;
}

.formula figcaption strong {
  color: var(--gold-soft);
}

/* ---------- 交互演示 ---------- */
.demo {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(26, 33, 56, 0.7), rgba(18, 24, 41, 0.35));
  overflow: hidden;
}

.demo__head {
  padding: 26px 28px 0;
}

.demo__title {
  font-size: 21px;
  margin: 0 0 8px;
}

.demo__hint {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  max-width: 62ch;
}

.demo__body {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 28px;
  padding: 26px 28px 30px;
}

.demo__cells {
  border: 0;
  margin: 0;
  padding: 0;
  min-width: 0;
}

.demo__legend {
  padding: 0 0 12px;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--muted-2);
}

.cell-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.cell-item label {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 12px;
  padding: 11px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  cursor: pointer;
  transition: border-color 0.16s ease, background 0.16s ease;
}

.cell-item label:hover {
  border-color: var(--line-strong);
  background: rgba(255, 255, 255, 0.03);
}

.cell-item input {
  width: 17px;
  height: 17px;
  accent-color: var(--gold);
  cursor: pointer;
  margin: 0;
}

.cell-item input:checked ~ .cell-item__text .cell-item__name {
  color: var(--gold-soft);
}

.cell-item label:has(input:checked) {
  border-color: rgba(232, 183, 97, 0.42);
  background: rgba(232, 183, 97, 0.07);
}

.cell-item__text {
  min-width: 0;
}

.cell-item__name {
  display: block;
  font-size: 15px;
}

.cell-item__meta {
  display: block;
  font-size: 12.5px;
  color: var(--muted-2);
  font-family: var(--mono);
}

.cell-item__gain {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--jade);
  white-space: nowrap;
}

/* 稀有度视觉提示 */
.cell-item--rare .cell-item__gain {
  color: var(--gold);
  font-weight: 600;
}

.demo__result {
  align-self: start;
  padding: 24px 22px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--ink);
  text-align: center;
}

.result__label {
  margin: 0;
  font-size: 12.5px;
  letter-spacing: 0.16em;
  color: var(--muted-2);
}

.result__score {
  margin: 6px 0 4px;
  font-family: var(--mono);
  font-size: 34px;
  color: var(--gold);
  font-variant-numeric: tabular-nums;
}

.result__tier {
  margin: 0 0 20px;
  font-family: var(--serif);
  font-size: 22px;
}

.result__meter {
  position: relative;
  height: 8px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  overflow: hidden;
}

.result__meter-fill {
  height: 100%;
  width: 0%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--jade), var(--gold));
  transition: width 0.35s cubic-bezier(0.22, 1, 0.36, 1);
}

.result__meter-marks span {
  position: absolute;
  top: -3px;
  width: 1px;
  height: 14px;
  background: rgba(255, 255, 255, 0.28);
}

/* 档位刻度:0 / 0.2 / 0.5,用类而非行内样式,便于收紧 CSP */
.mark--0 {
  left: 0%;
}

.mark--low {
  left: 40%;
}

.mark--high {
  left: 100%;
}

.result__scale {
  display: flex;
  justify-content: space-between;
  list-style: none;
  margin: 8px 0 18px;
  padding: 0;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--muted-2);
}

.result__note {
  margin: 0;
  font-size: 13.5px;
  color: var(--muted);
  min-height: 3em;
}

.tiers-note {
  margin: 34px 0 0;
  color: var(--muted);
  font-size: 15px;
}

.tag {
  display: inline-block;
  margin: 0 3px;
  padding: 3px 12px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  font-size: 13px;
  color: var(--text);
}

.tag--hot {
  border-color: rgba(232, 183, 97, 0.5);
  color: var(--gold);
}

/* ---------- 隐私 ---------- */
.section--panel {
  background: linear-gradient(180deg, rgba(18, 24, 41, 0.55), transparent);
}

.privacy-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 20px;
}

.pcard {
  padding: 28px 26px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--ink-2);
}

.pcard__title {
  font-size: 18px;
  margin: 0 0 16px;
}

.pcard ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
  font-size: 15.5px;
  color: var(--muted);
}

.pcard li {
  padding-left: 26px;
  position: relative;
}

.pcard li::before {
  position: absolute;
  left: 0;
  top: 0;
  font-family: var(--mono);
}

.pcard--no {
  border-color: rgba(224, 108, 108, 0.24);
}

.pcard--no li::before {
  content: "✕";
  color: #e06c6c;
}

.pcard--yes {
  border-color: rgba(111, 211, 199, 0.28);
}

.pcard--yes li::before {
  content: "✓";
  color: var(--jade);
}

/* ---------- 匿名信箱 ---------- */
.mailbox {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 44px;
  align-items: center;
}

.mailbox__copy p {
  font-size: 16.5px;
}

.chat {
  padding: 22px 20px;
  border: 1px solid var(--line-strong);
  border-radius: 18px;
  background: var(--ink-2);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
}

.chat__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.chat__who {
  font-family: var(--serif);
  font-size: 17px;
}

.chat__badge {
  padding: 3px 12px;
  border-radius: 999px;
  border: 1px solid rgba(232, 183, 97, 0.45);
  color: var(--gold);
  font-size: 12.5px;
}

.chat__meta {
  margin: 12px 0 18px;
  font-size: 13px;
  color: var(--muted-2);
}

.bubble {
  max-width: 85%;
  margin: 0 0 14px;
  padding: 12px 16px;
  border-radius: 14px;
  font-size: 15.5px;
}

.bubble p {
  margin: 0;
}

.bubble--in {
  background: var(--ink-3);
  border-top-left-radius: 4px;
}

.bubble--out {
  margin-left: auto;
  background: linear-gradient(135deg, rgba(232, 183, 97, 0.9), rgba(217, 159, 69, 0.85));
  color: #1a1206;
  border-top-right-radius: 4px;
}

.bubble__time {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  color: var(--muted-2);
}

.chat__unlock {
  margin: 6px 0 0;
  text-align: center;
  font-size: 12.5px;
  color: var(--jade);
  letter-spacing: 0.1em;
}

/* ---------- FAQ ---------- */
.faq {
  display: grid;
  gap: 12px;
}

.faq__item {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--ink-2);
  overflow: hidden;
}

.faq__item summary {
  padding: 18px 22px;
  cursor: pointer;
  font-size: 16.5px;
  font-family: var(--serif);
  list-style: none;
  position: relative;
  padding-right: 52px;
}

.faq__item summary::-webkit-details-marker {
  display: none;
}

.faq__item summary::after {
  content: "+";
  position: absolute;
  right: 22px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--gold);
  font-family: var(--mono);
  font-size: 20px;
}

.faq__item[open] summary::after {
  content: "−";
}

.faq__item[open] summary {
  border-bottom: 1px solid var(--line);
}

.faq__item p {
  margin: 0;
  padding: 18px 22px;
  color: var(--muted);
  font-size: 15.5px;
}

.faq__item strong {
  color: var(--gold-soft);
}

/* ---------- CTA ---------- */
.cta {
  max-width: 760px;
  margin: 0 auto;
  padding: 100px 24px;
  text-align: center;
  border-top: 1px solid var(--line);
}

.cta__title {
  font-size: clamp(24px, 4vw, 34px);
  margin: 0 0 16px;
}

.cta__sub {
  margin: 0 0 10px;
  color: var(--muted);
}

.cta__note {
  margin: 0;
  font-size: 13.5px;
  color: var(--muted-2);
}

/* ---------- 页脚 ---------- */
.site-footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid var(--line);
  background: rgba(9, 12, 22, 0.9);
}

.footer__inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 48px 24px 30px;
  display: flex;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
}

.footer__brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.footer__name {
  margin: 0;
  font-family: var(--serif);
  font-size: 18px;
  letter-spacing: 0.08em;
}

.footer__tag {
  margin: 0;
  font-size: 13.5px;
  color: var(--muted-2);
}

.footer__cols {
  display: flex;
  gap: 60px;
}

.footer__col h3 {
  margin: 0 0 12px;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--muted-2);
  font-family: var(--sans);
  font-weight: 600;
}

.footer__col ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
  font-size: 14.5px;
}

.footer__col a {
  color: var(--muted);
}

.footer__legal {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 20px 24px 40px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 13.5px;
  color: var(--muted-2);
}

.footer__legal p {
  margin: 0;
}

.footer__legal a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid var(--line);
}

.footer__legal a:hover,
.footer__legal a:focus-visible {
  color: var(--muted);
}

/* ---------- 入场动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s cubic-bezier(0.22, 1, 0.36, 1);
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .demo__body,
  .mailbox {
    grid-template-columns: 1fr;
  }

  .nav__links {
    display: none;
  }

  .section {
    padding: 68px 20px;
  }

  .hero {
    padding: 78px 20px 68px;
  }
}

@media (max-width: 560px) {
  body {
    font-size: 16px;
  }

  .cell-item label {
    grid-template-columns: auto 1fr;
  }

  .cell-item__gain {
    grid-column: 2;
  }

  .footer__cols {
    gap: 36px;
  }
}

/* ---------- 尊重系统减弱动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}