:root {
  --bg: #f6f7fb;
  --card: #ffffff;
  --cardBorder: rgba(13, 18, 28, 0.10);
  --hairline: rgba(13, 18, 28, 0.08);
  --text: rgba(13, 18, 28, 0.92);
  --muted: rgba(13, 18, 28, 0.62);
  --shadow: 0 10px 24px rgba(18, 25, 38, 0.08);
  --ring: 0 0 0 4px rgba(0, 122, 255, 0.18);
  --primary: #007aff;
  --radius: 18px;
  --radiusSm: 14px;
  --maxWidth: 1040px;
  --space: 12px;
  --pad: 12px;
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, "Noto Sans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

@media (max-width: 680px) {
  :root {
    --maxWidth: 100%;
  }
}

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

html,
body {
  height: 100%;
}

html {
  background: var(--bg);
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  color: var(--text);
  background: transparent;
  min-height: 100vh;
  line-height: 1.5;
}

.app {
  min-height: 100%;
  display: flex;
  flex-direction: column;
  padding: 14px 12px 18px;
}

.header,
.main,
.footer {
  width: 100%;
  max-width: var(--maxWidth);
  margin: 0 auto;
}

.header {
  margin-top: 6px;
  margin-bottom: 8px;
  text-align: center;
}

.brand {
  font-weight: 800;
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.header__titleRow {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 14px;
}

.eyebrow {
  font-size: 14px;
  color: var(--muted);
  letter-spacing: 0.06em;
}

.title {
  margin: 0;
  font-size: clamp(22px, 2.8vw, 32px);
  letter-spacing: -0.02em;
}

.subline {
  margin: 8px 0 0;
  color: var(--muted);
  line-height: 1.55;
  font-size: 14px;
}

.main {
  display: grid;
  gap: var(--space);
  margin-bottom: var(--space);
}

.card {
  background: var(--card);
  border: 1px solid var(--cardBorder);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
}

.card--padded {
  padding: var(--pad);
}

.card--flush {
  padding: 0;
  border: 0;
  box-shadow: none;
  border-radius: var(--radius);
  background: transparent;
}

.segmented {
  display: inline-grid;
  grid-auto-flow: column;
  gap: 6px;
  padding: 6px;
  border-radius: 999px;
  background: rgba(13, 18, 28, 0.04);
  border: 1px solid var(--hairline);
}

.segmented__item {
  appearance: none;
  border: 0;
  padding: 10px 14px;
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  transition: background 180ms ease, color 180ms ease, transform 180ms ease;
}

.segmented__item[aria-selected="true"] {
  background: var(--primary);
  color: #ffffff;
  box-shadow: none;
}

.segmented__item[aria-selected="true"]:focus-visible {
  box-shadow: var(--ring);
}

.segmented__item:active {
  transform: translateY(1px);
}

.segmented__item:focus-visible {
  outline: none;
  box-shadow: var(--ring);
}

.hostGrid {
  margin-top: 10px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

@media (max-width: 680px) {
  .hostGrid {
    grid-template-columns: 1fr;
  }
}

@media (min-width: 900px) {
  .hostGrid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* 手机端：只显示当前选中的主机图片，减少首屏占用 */
@media (max-width: 680px) {
  .hostGrid .hostTile {
    display: none;
  }
  .hostGrid .hostTile[data-active="true"] {
    display: grid;
  }
}

.hostTile {
  appearance: none;
  border: 1px solid var(--hairline);
  background: #ffffff;
  border-radius: var(--radiusSm);
  padding: 6px;
  display: grid;
  place-items: center;
  cursor: pointer;
  transition: transform 160ms ease, background 160ms ease, border-color 160ms ease, box-shadow 160ms ease;
  text-align: left;
}

.hostTile:hover {
  transform: translateY(-1px);
  box-shadow: none;
}

.hostTile:focus-visible {
  outline: none;
  box-shadow: var(--ring);
}

.hostTile[data-active="true"] {
  border-width: 2px;
  border-color: rgba(0, 122, 255, 0.9);
  box-shadow: 0 8px 18px rgba(0, 122, 255, 0.12);
}

.hostTile__img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: contain;
  object-position: center;
  border-radius: 12px;
  background: #ffffff;
  border: 0;
}

@media (max-width: 680px) {
  .hostTile__img {
    max-height: 160px;
  }
}

@media (max-width: 680px) {
  .hostTile__img {
    width: 100%;
  }
}

.hostTile__name {
  font-weight: 700;
  letter-spacing: -0.01em;
}

.hostTile__desc {
  margin-top: 6px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.4;
}

.tutorialHeader {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

@media (max-width: 640px) {
  .tutorialHeader {
    flex-direction: column;
    align-items: flex-start;
  }
}

.tutorialHeader__kicker {
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.06em;
}

.tutorialHeader__title {
  margin: 6px 0 0;
  font-size: 20px;
  letter-spacing: -0.015em;
}

.notice--tight {
  margin-top: 14px;
}

.step__tabs {
  padding: 10px 8px;
  display: flex;
  justify-content: flex-start;
  border-bottom: 1px solid var(--hairline);
  background: #ffffff;
}

.button {
  appearance: none;
  border: 1px solid rgba(0, 0, 0, 0.12);
  background: rgba(255, 255, 255, 0.9);
  color: var(--text);
  border-radius: 0;
  padding: 10px 14px;
  font-weight: 650;
  font-size: 16px;
  cursor: pointer;
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

.button--ghost {
  background: transparent;
}

.button:active {
  transform: translateY(1px);
}

.button:focus-visible {
  outline: none;
  box-shadow: var(--ring);
}

.notice {
  margin-top: 14px;
  padding: 12px 12px;
  border-radius: var(--radiusSm);
  border: 1px solid rgba(0, 0, 0, 0.08);
  background: rgba(255, 255, 255, 0.6);
}

.notice__title {
  font-weight: 800;
  font-size: 15px;
  letter-spacing: -0.01em;
}

.notice__body {
  margin-top: 6px;
  color: var(--muted);
  line-height: 1.55;
  font-size: 15px;
}

.steps {
  margin: 10px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.step {
  border: 0;
  border-radius: 0;
  overflow: hidden;
  background: #ffffff;
  box-shadow: none;
  border: 1px solid var(--hairline);
}

.step__top {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  background: rgba(13, 18, 28, 0.02);
  border-bottom: 1px solid var(--hairline);
}

.step__title {
  font-weight: 800;
  letter-spacing: -0.01em;
  font-size: 15px;
}

.step__meta {
  margin-left: auto;
  color: var(--muted);
  font-size: 12px;
  white-space: nowrap;
  opacity: 0.8;
}

.step__content {
  padding: 0 10px 10px;
  color: var(--muted);
  line-height: 1.55;
  font-size: 13px;
}

.step__lineList {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.step__lineList-item {
  position: relative;
  padding-left: 14px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}

.step__lineList-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.58em;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--muted);
  opacity: 0.45;
}

.step__lineList-item--lead {
  color: var(--text);
  font-weight: 700;
  letter-spacing: -0.01em;
  opacity: 0.92;
}

.step__lineList-item--lead::before {
  background: var(--text);
  opacity: 0.4;
}

.step__media {
  padding: 0;
  display: grid;
  gap: 10px;
}

@media (max-width: 680px) {
  .steps {
    gap: 12px;
  }
  .step {
    border-radius: 0;
  }
}

.step__footer {
  padding: 20px 10px 10px;
  border-top: 1px solid var(--hairline);
  background: #ffffff;
}

.step__bigNote {
  text-align: center;
  font-weight: 850;
  font-size: clamp(14px, 1.8vw, 18px);
  line-height: 1.25;
  letter-spacing: -0.015em;
  color: var(--text);
  padding: 10px 10px;
  border-radius: 0;
  border: 1px solid var(--hairline);
  background: rgba(0, 122, 255, 0.05);
}

.step__gate {
  margin-top: 10px;
  padding: 10px;
  border-radius: 0;
  border: 1px solid var(--hairline);
  background: rgba(13, 18, 28, 0.02);
  text-align: center;
}

.step__gateTitle {
  font-weight: 900;
  font-size: clamp(16px, 2.0vw, 22px);
  letter-spacing: -0.015em;
}

.step__gateActions {
  margin-top: 10px;
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
}

.gateBtn {
  appearance: none;
  border: 0;
  border-radius: 999px;
  padding: 12px 16px;
  font-weight: 900;
  font-size: 16px;
  cursor: pointer;
  background: var(--primary);
  color: #fff;
  box-shadow: none;
}

.gateBtn[aria-pressed="true"] {
  transform: translateY(1px);
  box-shadow: none;
}

.gateBtn[aria-pressed="false"] {
  opacity: 0.92;
}

.gateBtn:focus-visible {
  outline: none;
  box-shadow: var(--ring);
}

.gateBtn--ghost {
  background: rgba(13, 18, 28, 0.06);
  color: var(--text);
  border: 1px solid rgba(0, 0, 0, 0.14);
  box-shadow: none;
}

.gateBtn--ghost[aria-pressed="true"] {
  background: rgba(0, 122, 255, 0.14);
  border-color: rgba(0, 122, 255, 0.55);
  color: var(--text);
}

.step__gateHelp {
  margin-top: 10px;
  font-size: 14px;
  color: var(--muted);
  line-height: 1.5;
}

.step__img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 0;
  border: 0;
  background: transparent;
}

/* 绿联风格：图片不做 viewport 拉伸，保持卡片内阅读舒适 */

.sectionTitle {
  margin: 0 0 10px;
  font-size: 16px;
  letter-spacing: -0.01em;
  opacity: 0.85;
}

.faq {
  display: grid;
  gap: 10px;
}

.faq__item {
  border: 1px solid rgba(0, 0, 0, 0.08);
  border-radius: var(--radiusSm);
  background: rgba(255, 255, 255, 0.92);
  padding: 10px 12px;
}

.faq__item > summary {
  cursor: pointer;
  font-weight: 750;
  font-size: 14px;
}

.faq__body {
  margin-top: 8px;
  color: var(--muted);
  line-height: 1.55;
  font-size: 13px;
}

.footer {
  margin-top: auto;
  padding-top: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--muted);
  font-size: 11px;
  gap: 12px;
  opacity: 0.8;
}

.footer__left {
  display: flex;
  align-items: center;
  gap: 8px;
}

.dot {
  width: 8px;
  height: 8px;
  border-radius: 0;
  background: rgba(52, 199, 89, 0.9);
  box-shadow: 0 0 0 3px rgba(52, 199, 89, 0.18);
}

@media print {
  body {
    background: #fff;
  }
  .app {
    padding: 0;
  }
  .card {
    box-shadow: none;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
  }
  .header__right,
  .segmented,
  .hostGrid,
  .footer {
    display: none !important;
  }
}