.page-about {
  --pa-gap: clamp(14px, 2.2vw, 24px);
  --pa-soft: rgba(22, 53, 95, 0.55);
  --pa-hair: rgba(38, 227, 216, 0.28);
  position: relative;
  color: var(--text);
  background:
    radial-gradient(58% 40% at 10% 0%, rgba(38, 227, 216, 0.10), transparent 72%),
    radial-gradient(52% 36% at 94% 4%, rgba(22, 53, 95, 0.75), transparent 74%),
    var(--ink);
  padding-bottom: clamp(48px, 7vw, 96px);
  overflow-x: hidden;
}

.page-about a { color: var(--cyan); text-decoration: none; }
.page-about a:hover,
.page-about a:focus-visible { color: var(--cyan-soft); }

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--sans);
  font-weight: 800;
  letter-spacing: 0.04em;
  line-height: 1.18;
  margin: 0;
}

.page-about p { margin: 0; }

.page-about .container {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding-inline: var(--pad);
}

/* ---------- 首屏 ---------- */
.about-hero { padding-top: clamp(18px, 3vw, 40px); }

.about-hero__inner {
  display: grid;
  gap: clamp(22px, 3.6vw, 44px);
  align-items: end;
}

.about-hero__eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 16px 0 12px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--muted);
}

.about-hero__code {
  padding: 3px 8px;
  color: var(--cyan);
  border: 1px solid var(--pa-hair);
  clip-path: var(--cut-corner);
  background: rgba(38, 227, 216, 0.06);
}

.page-about .about-hero h1 {
  font-size: clamp(30px, 7vw, 58px);
  max-width: 15ch;
  padding-bottom: 12px;
  border-bottom: 3px solid var(--cyan);
  display: inline-block;
}

.about-hero__lede {
  margin-top: clamp(16px, 2.4vw, 22px);
  max-width: 46ch;
  font-size: clamp(14px, 1.6vw, 16px);
  line-height: 1.85;
  color: rgba(234, 242, 255, 0.88);
}

.about-hero__meta {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 16px;
  margin: 20px 0 0;
  padding: 0;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.about-hero__meta li { display: inline-flex; align-items: center; gap: 6px; }
.about-hero__meta li + li::before {
  content: "";
  width: 1px;
  height: 10px;
  background: var(--line);
  margin-right: 4px;
}

.about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.about-hero__actions .btn { clip-path: var(--cut-corner); padding: 12px 22px; font-size: 14px; }

.about-hero__figure { margin: 0; }

.page-about .media-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  clip-path: var(--cut-corner);
  background: linear-gradient(150deg, var(--ink-2), #061225 70%);
  box-shadow: inset 0 1px 0 rgba(38, 227, 216, 0.18);
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .media-frame--tall img { aspect-ratio: 4 / 3; }
.page-about .media-frame--wide img { aspect-ratio: 3 / 2; }

.about-hero__figure figcaption,
.checklist-figure figcaption,
.upgrade__figure figcaption {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 区块标题 ---------- */
.page-about .sec-head {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: 64ch;
  margin-bottom: clamp(20px, 3vw, 32px);
}

.sec-head__no {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--cyan);
}

.page-about .sec-head h2 {
  font-size: clamp(21px, 3.4vw, 32px);
}

.page-about .sec-head p {
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 会员体系总览 ---------- */
.page-about .tier-overview { padding-top: clamp(46px, 7vw, 88px); }

.tier-cards {
  list-style: none;
  display: grid;
  gap: var(--pa-gap);
  margin: 0;
  padding: 0;
}

.tier-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: clamp(18px, 2.4vw, 26px);
  border: 1px solid var(--line);
  clip-path: var(--cut-corner);
  background: linear-gradient(155deg, var(--ink-2), #071528 78%);
}

.tier-card--pick {
  border-color: var(--pa-hair);
  background: linear-gradient(155deg, rgba(38, 227, 216, 0.10), var(--ink-2) 46%, #061428 92%);
}

.tier-card--pick::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
}

.tier-card__badge {
  position: absolute;
  top: 0;
  right: 0;
  padding: 4px 12px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: #0b1220;
  background: var(--signal);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 10px 100%);
}

.tier-card__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
  padding-right: 76px;
}

.tier-card__name { font-size: clamp(18px, 2.2vw, 21px); }

.tier-card__flag {
  padding: 3px 9px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  border: 1px solid var(--pa-hair);
  border-radius: 999px;
}

.tier-card__flag--calm { color: var(--muted); border-color: var(--line); }
.tier-card__flag--warm { color: var(--warn); border-color: rgba(255, 194, 75, 0.4); }

.tier-card__lead {
  font-size: 13.5px;
  line-height: 1.8;
  color: rgba(234, 242, 255, 0.82);
}

.tier-card__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

.tier-card__list li {
  position: relative;
  padding-left: 16px;
}

.tier-card__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 6px;
  height: 6px;
  background: var(--cyan);
  transform: rotate(45deg);
}

/* ---------- 对照矩阵 ---------- */
.page-about .matrix-section { padding-top: clamp(46px, 7vw, 88px); }

.matrix-block {
  position: relative;
  padding: clamp(16px, 2.4vw, 28px);
  border: 1px solid var(--line);
  clip-path: var(--cut-corner);
  background: linear-gradient(180deg, rgba(10, 27, 54, 0.92), rgba(6, 18, 37, 0.92));
}

.matrix-radio,
.scope-radio {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.matrix-switch,
.scope-switch {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.matrix-switch { display: none; }

.matrix-switch__label,
.scope-switch__label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 15px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(5, 15, 34, 0.6);
  cursor: pointer;
  transition: color 120ms ease, border-color 120ms ease, background-color 120ms ease;
}

.matrix-switch__label:hover,
.scope-switch__label:hover { color: var(--text); border-color: var(--pa-hair); }

.scope-switch__num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--cyan);
}

#tier-base:checked ~ .matrix-switch label[for="tier-base"],
#tier-adv:checked ~ .matrix-switch label[for="tier-adv"],
#tier-sup:checked ~ .matrix-switch label[for="tier-sup"],
#scope-all:checked ~ .scope-switch label[for="scope-all"],
#scope-base:checked ~ .scope-switch label[for="scope-base"],
#scope-adv:checked ~ .scope-switch label[for="scope-adv"],
#scope-sup:checked ~ .scope-switch label[for="scope-sup"] {
  color: #06121f;
  border-color: var(--cyan);
  background: var(--cyan);
}

#tier-base:checked ~ .matrix-switch label[for="tier-base"] .scope-switch__num,
#scope-base:checked ~ .scope-switch label[for="scope-base"] .scope-switch__num,
#scope-adv:checked ~ .scope-switch label[for="scope-adv"] .scope-switch__num,
#scope-sup:checked ~ .scope-switch label[for="scope-sup"] .scope-switch__num,
#scope-all:checked ~ .scope-switch label[for="scope-all"] .scope-switch__num { color: #06121f; }

#tier-base:focus-visible ~ .matrix-switch label[for="tier-base"],
#tier-adv:focus-visible ~ .matrix-switch label[for="tier-adv"],
#tier-sup:focus-visible ~ .matrix-switch label[for="tier-sup"],
#scope-all:focus-visible ~ .scope-switch label[for="scope-all"],
#scope-base:focus-visible ~ .scope-switch label[for="scope-base"],
#scope-adv:focus-visible ~ .scope-switch label[for="scope-adv"],
#scope-sup:focus-visible ~ .scope-switch label[for="scope-sup"] {
  outline: 2px solid var(--cyan-soft);
  outline-offset: 2px;
}

.matrix-scroll { width: 100%; }

.matrix {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  line-height: 1.6;
}

.matrix thead th {
  position: sticky;
  top: 72px;
  z-index: 2;
  padding: 10px 12px;
  text-align: left;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--text);
  background: #0b1d38;
  border-bottom: 1px solid var(--pa-hair);
}

.matrix thead th:first-child { color: var(--muted); }

.matrix tbody th,
.matrix tbody td {
  padding: 12px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px dashed rgba(22, 53, 95, 0.75);
  font-weight: 400;
}

.matrix__rowhead {
  color: var(--text);
  font-weight: 600;
}

.matrix tbody td { color: var(--muted); }

.matrix__group th {
  padding: 18px 12px 8px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan);
  border-bottom: 1px solid var(--line);
  background: rgba(38, 227, 216, 0.05);
}

.matrix__yes { color: var(--ok); }
.matrix__none { color: rgba(147, 167, 198, 0.7); }

.matrix__note {
  margin-top: 14px;
  font-size: 12px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 服务清单 ---------- */
.page-about .checklist-area { padding-top: clamp(46px, 7vw, 88px); }

.checklist-figure {
  margin: 0 0 clamp(22px, 3vw, 34px);
}

.checklist-figure .media-frame { max-width: 780px; }

.checklist-layout {
  display: grid;
  gap: var(--pa-gap);
  align-items: start;
}

.cl-nav {
  display: none;
  position: sticky;
  top: 96px;
  flex-direction: column;
  gap: 2px;
  padding: 12px;
  border: 1px solid var(--line);
  clip-path: var(--cut-corner);
  background: rgba(10, 27, 54, 0.7);
}

.cl-nav__link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 10px;
  font-size: 13px;
  color: rgba(234, 242, 255, 0.85);
  border-left: 2px solid transparent;
  transition: background-color 120ms ease, border-color 120ms ease, color 120ms ease;
}

.cl-nav__link:hover,
.cl-nav__link:focus-visible {
  color: var(--cyan);
  background: rgba(38, 227, 216, 0.08);
  border-left-color: var(--cyan);
}

.cl-nav__no {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
}

.cl-nav__count {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
}

.page-about .cl-cat {
  padding: 0 0 6px;
  margin-bottom: 26px;
  scroll-margin-top: 96px;
}

.page-about .cl-cat:target .cl-cat__head {
  border-bottom-color: var(--cyan);
}

.cl-cat__head {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 6px;
}

.cl-cat__no {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--cyan);
}

.page-about .cl-cat__head h3 { font-size: 17px; }

.cl-cat__count {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
}

.check-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.check-item {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 10px 12px;
  padding: 13px 4px;
  border-bottom: 1px dashed rgba(22, 53, 95, 0.65);
}

.check-item__box {
  appearance: none;
  -webkit-appearance: none;
  position: relative;
  flex: none;
  width: 18px;
  height: 18px;
  margin: 3px 0 0;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: rgba(5, 15, 34, 0.75);
  cursor: pointer;
  transition: border-color 120ms ease, background-color 120ms ease;
}

.check-item__box:hover { border-color: var(--pa-hair); }

.check-item__box:checked {
  border-color: var(--cyan);
  background: rgba(38, 227, 216, 0.18);
}

.check-item__box:checked::after {
  content: "";
  position: absolute;
  left: 5px;
  top: 1px;
  width: 5px;
  height: 10px;
  border-right: 2px solid var(--cyan);
  border-bottom: 2px solid var(--cyan);
  transform: rotate(40deg);
}

.check-item__box:focus-visible {
  outline: 2px solid var(--cyan-soft);
  outline-offset: 2px;
}

.check-item__label {
  flex: 1 1 220px;
  min-width: 0;
  cursor: pointer;
}

.check-item__no {
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.check-item__name {
  display: block;
  margin-top: 2px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
}

.check-item__desc {
  display: block;
  margin-top: 4px;
  font-size: 12.5px;
  line-height: 1.75;
  color: var(--muted);
}

.check-item__tier {
  flex: none;
  margin-left: auto;
  padding: 2px 9px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  border: 1px solid var(--pa-hair);
  border-radius: 999px;
  white-space: nowrap;
}

.check-item__box:checked ~ .check-item__label .check-item__name { color: var(--cyan); }
.check-item__box:checked ~ .check-item__label .check-item__no { color: var(--cyan-soft); }

#scope-base:checked ~ .checklist [data-tier="adv"],
#scope-base:checked ~ .checklist [data-tier="sup"],
#scope-adv:checked ~ .checklist [data-tier="base"],
#scope-adv:checked ~ .checklist [data-tier="sup"],
#scope-sup:checked ~ .checklist [data-tier="base"],
#scope-sup:checked ~ .checklist [data-tier="adv"] {
  display: none;
}

/* ---------- 升级续期 ---------- */
.page-about .upgrade { padding-top: clamp(46px, 7vw, 88px); }

.upgrade__grid {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
  align-items: start;
}

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.step {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--cyan);
  clip-path: var(--cut-corner);
  background: linear-gradient(120deg, rgba(22, 53, 95, 0.4), rgba(6, 18, 37, 0.6));
}

.step__no {
  flex: none;
  width: 72px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--cyan);
  padding-top: 4px;
}

.step__body { flex: 1 1 240px; min-width: 0; }
.step__body h3 { font-size: 16px; margin-bottom: 6px; }
.step__body p { font-size: 13.5px; line-height: 1.8; color: var(--muted); }

.upgrade__tip {
  margin-top: 16px;
  padding: 14px 16px;
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
  border: 1px dashed var(--pa-hair);
  border-radius: 2px;
  background: rgba(38, 227, 216, 0.04);
}

.upgrade__figure { margin: 0; }

/* ---------- 常见疑问 ---------- */
.page-about .faq { padding-top: clamp(46px, 7vw, 88px); }

.faq__list {
  border-top: 1px solid var(--line);
}

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

.faq__q {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 2px;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.6;
  color: var(--text);
  cursor: pointer;
  list-style: none;
}

.faq__q::-webkit-details-marker { display: none; }

.faq__q::after {
  content: "+";
  flex: none;
  font-family: var(--mono);
  font-size: 18px;
  line-height: 1.2;
  color: var(--cyan);
}

.faq__item[open] .faq__q::after { content: "−"; }
.faq__item[open] .faq__q { color: var(--cyan); }

.faq__q:focus-visible {
  outline: 2px solid var(--cyan-soft);
  outline-offset: 2px;
}

.faq__a {
  padding: 0 2px 16px;
  max-width: 68ch;
}

.faq__a p {
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 联系协助 ---------- */
.page-about .assist { padding-top: clamp(46px, 7vw, 88px); }

.assist__grid {
  display: grid;
  gap: var(--pa-gap);
  align-items: stretch;
}

.assist__intro {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: flex-start;
  padding: clamp(20px, 3vw, 30px);
  border: 1px solid var(--line);
  clip-path: var(--cut-corner);
  background: linear-gradient(150deg, rgba(38, 227, 216, 0.08), rgba(6, 18, 37, 0.7) 60%);
}

.assist__intro h2 { font-size: clamp(20px, 3vw, 28px); max-width: 20ch; }
.assist__intro p { font-size: 14px; line-height: 1.85; color: rgba(234, 242, 255, 0.85); max-width: 44ch; }
.assist__intro .btn { margin-top: 6px; clip-path: var(--cut-corner); padding: 11px 20px; font-size: 14px; }

.assist__panel {
  padding: clamp(20px, 3vw, 30px);
  border: 1px solid var(--line);
  clip-path: var(--cut-corner);
  background: rgba(10, 27, 54, 0.72);
}

.assist__panel-title {
  font-size: 15px;
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.assist__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--text);
}

.assist__list li {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 12px;
}

.assist__key {
  flex: none;
  width: 72px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--cyan);
  padding-top: 3px;
}

.assist__note {
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 断点 ---------- */
@media (max-width: 767px) {
  .page-about .matrix-switch { display: flex; }

  .matrix thead th { top: 58px; }

  .matrix thead th[data-tier],
  .matrix tbody td[data-tier] { display: none; }

  #tier-base:checked ~ .matrix-scroll .matrix [data-tier="base"],
  #tier-adv:checked ~ .matrix-scroll .matrix [data-tier="adv"],
  #tier-sup:checked ~ .matrix-scroll .matrix [data-tier="sup"] {
    display: table-cell;
  }

  .matrix thead th:first-child { width: 46%; }

  .matrix__group th { padding-top: 15px; }

  .check-item__tier { margin-left: 28px; }
}

@media (min-width: 768px) {
  .matrix-switch { display: none; }
}

@media (min-width: 900px) {
  .about-hero__inner {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  }

  .tier-cards {
    grid-template-columns: 1fr 1.12fr 1fr;
    align-items: stretch;
  }

  .tier-card--pick { transform: translateY(-10px); }

  .checklist-layout {
    grid-template-columns: 236px minmax(0, 1fr);
    gap: clamp(20px, 3vw, 40px);
  }

  .cl-nav { display: flex; }

  .upgrade__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  }

  .assist__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  }
}

@media (min-width: 1180px) {
  .checklist-layout { grid-template-columns: 260px minmax(0, 1fr); }
  .matrix { font-size: 14px; }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition: none !important;
    animation: none !important;
  }
  .tier-card--pick { transform: none; }
}