:root {
  --page-max: 52rem;
  --bg: #f6f7fb;
  --text: #111827;
  --muted: rgba(0, 0, 0, 0.65);
  --border: rgba(0, 0, 0, 0.12);
  --card: #ffffff;
  --shadow: 0 10px 30px rgba(17, 24, 39, 0.08);
  --shadow-sm: 0 6px 16px rgba(17, 24, 39, 0.06);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, "PingFang SC", "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
  line-height: 1.75;
}

a {
  color: #0f766e;
  text-decoration: none;
}

a:hover { text-decoration: underline; }

p { margin: 0.75rem 0; }

h1, h2, h3 {
  line-height: 1.25;
  letter-spacing: -0.01em;
}

h1 { font-size: 1.6rem; margin: 0.6rem 0 0.9rem; }
h2 {
  font-size: 1.25rem;
  margin: 1.6rem 0 0.85rem;
  padding: 10px 12px;
  border-radius: 12px;
  border: 1px solid rgba(0,0,0,0.10);
  border-left: 6px solid rgba(15, 118, 110, 0.75);
  background: rgba(15, 118, 110, 0.06);
}

.section-body {
  margin: -0.3rem 0 1.15rem;
  padding: 12px 12px;
  border-radius: 12px;
  border: 1px solid rgba(0,0,0,0.08);
  background: rgba(0,0,0,0.015);
}

.section-body > :first-child {
  margin-top: 0;
}

.section-body > :last-child {
  margin-bottom: 0;
}

h3 {
  font-size: 1.08rem;
  margin: 1.1rem 0 0.55rem;
  padding: 6px 10px;
  border-radius: 10px;
  border: 1px solid rgba(0,0,0,0.08);
  border-left: 4px solid rgba(37, 99, 235, 0.85);
  background: #ffffff;
}

h2, h3 {
  scroll-margin-top: 90px;
}

ul, ol {
  padding-left: 1.25rem;
}

.main-content > ul,
.main-content > ol {
  margin: 0.7rem 0 0.9rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  border-spacing: 0;
  margin: 0.75rem 0;
  background: #fff;
  border: 1px solid rgba(0,0,0,0.12);
  border-radius: 12px;
  overflow: hidden;
}

th, td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid rgba(0,0,0,0.08);
  vertical-align: top;
}

thead th {
  background: rgba(0,0,0,0.03);
  font-weight: 800;
}

tbody tr:last-child td {
  border-bottom: 0;
}

ul.vpn-overview {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

ul.vpn-overview > li {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.25rem 0;
}

.vpn-overview-title {
  flex: 0 0 16rem;
}

.vpn-overview-desc {
  flex: 1 1 auto;
  color: rgba(0, 0, 0, 0.75);
}

@media (max-width: 540px) {
  ul.vpn-overview > li {
    flex-wrap: wrap;
  }

  .vpn-overview-title {
    flex: 0 0 auto;
  }
}

li { margin: 0.25rem 0; }

hr {
  border: 0;
  border-top: 1px solid var(--border);
  margin: 1.35rem 0;
}

blockquote {
  margin: 0.9rem 0;
  padding: 12px 14px;
  border: 1px solid rgba(245, 158, 11, 0.20);
  border-left: 4px solid rgba(245, 158, 11, 0.65);
  border-radius: 10px;
  background: rgba(245, 158, 11, 0.08);
  color: rgba(0, 0, 0, 0.75);
}

.notice {
  margin: 10px 0 16px;
  padding: 10px 12px;
  border: 1px solid rgba(0,0,0,0.12);
  border-radius: 8px;
  background: rgba(0,0,0,0.03);
  color: rgba(0,0,0,0.75);
  line-height: 1.7;
}

.cta-group {
  margin: 12px 0;
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.cta-group a {
  display: inline-block;
  padding: 10px 14px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 800;
  border: 1px solid rgba(0,0,0,0.18);
  color: #111827;
  background: #fff;
}

.cta-group a:hover {
  text-decoration: none;
  filter: brightness(0.98);
}

.cta-group a.cta-primary {
  background: #0f766e;
  color: #fff;
  border-color: rgba(15, 118, 110, 0.45);
}

.cta-group a.cta-secondary {
  background: #ffffff;
}

.faq {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.faq-item {
  border: 1px solid rgba(0,0,0,0.12);
  border-radius: 12px;
  background: #fff;
  overflow: hidden;
}

.faq-item > summary {
  list-style: none;
  cursor: pointer;
  font-weight: 800;
  padding: 12px 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.faq-item > summary::marker {
  content: "";
}

.faq-item > summary::-webkit-details-marker {
  display: none;
}

.faq-item > summary::after {
  content: "▾";
  color: rgba(0,0,0,0.55);
  font-weight: 900;
  transition: transform 0.18s ease;
}

.faq-item[open] > summary {
  background: rgba(15, 118, 110, 0.06);
}

.faq-item[open] > summary::after {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 14px 12px;
  color: rgba(0,0,0,0.78);
}

.faq-answer p {
  margin: 0.5rem 0 0;
}

.page-header {
  padding: 22px 16px 14px;
  text-align: center;
  background: linear-gradient(120deg, #155799, #159957);
  color: #fff;
}

.project-name {
  margin: 0;
  font-size: 28px;
  line-height: 1.2;
}

.project-tagline {
  margin: 10px auto 0;
  font-size: 16px;
  font-weight: 400;
  opacity: 0.92;
  max-width: var(--page-max);
}

.header-notice {
  max-width: var(--page-max);
  margin: 12px auto 10px;
  padding: 10px 12px;
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.14);
  font-size: 14px;
  line-height: 1.6;
}

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

.btn {
  display: inline-block;
  padding: 10px 14px;
  border-radius: 8px;
  text-decoration: none;
  background: rgba(255, 255, 255, 0.16);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.22);
  font-weight: 700;
  box-shadow: 0 1px 0 rgba(0,0,0,0.08);
}

#lang-select {
  -webkit-appearance: none;
  appearance: none;
  background: rgba(255, 255, 255, 0.16);
  color: #fff;
  padding-right: 30px;
  text-align: center;
  text-align-last: center;
}

#lang-select option {
  background: #ffffff;
  color: #111827;
  font-weight: 700;
  text-align: center;
}

.main-content {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 18px 16px 48px;
}

#content {
  background: var(--card);
  border: 1px solid rgba(0,0,0,0.08);
  border-radius: 14px;
  box-shadow: var(--shadow);
  margin-top: 16px;
}

.main-content {
  padding: 22px 18px 52px;
}

.site-footer {
  margin-top: 26px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 768px) {
  .project-name { font-size: 22px; }
  .project-tagline { font-size: 14px; }
  .btn {
    padding: 10px 12px;
  }

  #content {
    border-radius: 12px;
    margin-top: 12px;
  }

  .main-content {
    padding: 18px 14px 44px;
  }
}