/* ============================================================
   SafeW 安全加密即时通讯平台 — 全局样式表
   版本: 2.0.0 | 最后更新: 2026-08
   ============================================================ */

:root {
  --brand: #1a6ef0;
  --brand-dark: #1356c4;
  --brand-light: #e8f1fd;
  --brand-glow: rgba(26, 110, 240, 0.12);
  --accent: #10b981;
  --accent-dark: #059669;
  --warn: #f59e0b;
  --danger: #ef4444;
  --slate-50: #f8fafc;
  --slate-100: #f1f5f9;
  --slate-200: #e2e8f0;
  --slate-300: #cbd5e1;
  --slate-400: #94a3b8;
  --slate-500: #64748b;
  --slate-600: #475569;
  --slate-700: #334155;
  --slate-800: #1e293b;
  --slate-900: #0f172a;
  --white: #ffffff;
  --black: #0a0a0b;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.08);
  --shadow-xl: 0 20px 50px rgba(0,0,0,0.1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --duration: 220ms;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--slate-800);
  background: var(--white);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---- layout ---- */
.wrap {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

.wrap--narrow {
  max-width: 860px;
}

section {
  padding: 88px 0;
}

.section-label {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--brand);
  background: var(--brand-light);
  padding: 5px 14px;
  border-radius: 20px;
  margin-bottom: 16px;
}

.section-title {
  font-size: 2.15rem;
  font-weight: 700;
  color: var(--slate-900);
  margin-bottom: 14px;
  letter-spacing: -0.02em;
  line-height: 1.3;
}

.section-sub {
  font-size: 1.05rem;
  color: var(--slate-500);
  line-height: 1.7;
  max-width: 680px;
}

/* ---- header ---- */
.site-header {
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--slate-200);
  position: sticky;
  top: 0;
  z-index: 1100;
}

.nav-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
}

.logo-wrap {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.logo-img {
  width: 42px;
  height: 42px;
  object-fit: contain;
}

.logo-text {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--slate-900);
  letter-spacing: -0.01em;
}

.main-nav {
  display: flex;
  list-style: none;
  gap: 38px;
  align-items: center;
}

.main-nav a {
  text-decoration: none;
  color: var(--slate-700);
  font-size: 1.05rem;
  font-weight: 500;
  transition: color var(--duration) var(--ease-out);
  position: relative;
}

.main-nav a::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--brand);
  border-radius: 2px;
  transition: width var(--duration) var(--ease-out);
}

.main-nav a:hover,
.main-nav a.active {
  color: var(--brand);
}

.main-nav a:hover::after,
.main-nav a.active::after {
  width: 100%;
}

.nav-cta {
  background: var(--brand);
  color: var(--white) !important;
  padding: 10px 22px;
  border-radius: var(--radius-sm);
  font-weight: 500;
  transition: background var(--duration) var(--ease-out), box-shadow var(--duration) var(--ease-out) !important;
}

.nav-cta:hover {
  background: var(--brand-dark);
  box-shadow: 0 4px 16px var(--brand-glow);
}

.nav-cta::after {
  display: none !important;
}

/* ---- hero ---- */
.hero {
  padding: 100px 0 88px;
  background: linear-gradient(170deg, #f0f6fe 0%, #f8fafd 50%, var(--white) 100%);
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 56px;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--white);
  border: 1px solid var(--slate-200);
  padding: 8px 18px;
  border-radius: 24px;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--slate-600);
  margin-bottom: 24px;
}

.hero-badge .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.6); }
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--slate-900);
  margin-bottom: 20px;
}

.hero-title span {
  color: var(--brand);
}

.hero-desc {
  font-size: 1.1rem;
  color: var(--slate-500);
  line-height: 1.7;
  margin-bottom: 32px;
  max-width: 540px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 30px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: all var(--duration) var(--ease-out);
  line-height: 1.4;
}

.btn--fill {
  background: var(--brand);
  color: var(--white);
}

.btn--fill:hover {
  background: var(--brand-dark);
  box-shadow: 0 6px 24px rgba(26,110,240,0.25);
  transform: translateY(-1px);
}

.btn--edge {
  border: 2px solid var(--slate-300);
  color: var(--slate-700);
  background: transparent;
}

.btn--edge:hover {
  border-color: var(--brand);
  color: var(--brand);
  background: var(--brand-light);
}

.btn--lg {
  padding: 15px 36px;
  font-size: 1.08rem;
}

.btn--sm {
  padding: 8px 18px;
  font-size: 0.9rem;
}

.hero-media {
  position: relative;
}

.hero-media img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
}

.hero-media::before {
  content: '';
  position: absolute;
  top: -20px;
  right: -20px;
  width: 100%;
  height: 100%;
  background: var(--brand);
  border-radius: var(--radius-lg);
  opacity: 0.06;
  z-index: -1;
}

/* ---- trust bar ---- */
.trust-bar {
  padding: 32px 0;
  border-top: 1px solid var(--slate-100);
  border-bottom: 1px solid var(--slate-100);
  background: var(--slate-50);
}

.trust-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}

.trust-item .num {
  font-size: 2rem;
  font-weight: 800;
  color: var(--brand);
  letter-spacing: -0.02em;
}

.trust-item .lbl {
  font-size: 0.88rem;
  color: var(--slate-500);
  margin-top: 4px;
}

/* ---- feature cards ---- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-top: 48px;
}

.feat-card {
  background: var(--white);
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-md);
  padding: 34px 28px;
  transition: all var(--duration) var(--ease-out);
}

.feat-card:hover {
  border-color: var(--brand);
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
}

.feat-icon {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--brand-light);
  border-radius: var(--radius-sm);
  color: var(--brand);
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.feat-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--slate-900);
}

.feat-card p {
  font-size: 0.93rem;
  color: var(--slate-500);
  line-height: 1.65;
}

/* ---- two-col ---- */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
}

.two-col--rtl {
  direction: ltr;
}

.two-col--rtl .two-col-text {
  order: 1;
}

.two-col--rtl .two-col-media {
  order: 0;
}

.two-col-text h2 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--slate-900);
  letter-spacing: -0.02em;
  line-height: 1.3;
  margin-bottom: 14px;
}

.two-col-text p {
  font-size: 1rem;
  color: var(--slate-500);
  line-height: 1.7;
  margin-bottom: 12px;
}

.two-col-media img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
}

.check-list {
  list-style: none;
  margin-top: 16px;
}

.check-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 10px;
  font-size: 0.95rem;
  color: var(--slate-700);
}

.check-list li i {
  color: var(--accent);
  margin-top: 3px;
  flex-shrink: 0;
}

/* ---- cta banner ---- */
.cta-banner {
  background: linear-gradient(135deg, var(--brand) 0%, #0f5dc7 100%);
  border-radius: var(--radius-lg);
  padding: 64px 48px;
  text-align: center;
  color: var(--white);
}

.cta-banner h2 {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 14px;
}

.cta-banner p {
  font-size: 1.05rem;
  opacity: 0.88;
  margin-bottom: 28px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

.cta-banner .btn--fill {
  background: var(--white);
  color: var(--brand);
  font-weight: 700;
}

.cta-banner .btn--fill:hover {
  background: var(--slate-100);
  box-shadow: 0 8px 28px rgba(0,0,0,0.18);
}

/* ---- page hero (inner pages) ---- */
.page-hero {
  padding: 72px 0 60px;
  background: linear-gradient(170deg, #f0f6fe 0%, #f8fafd 100%);
  text-align: center;
}

.page-hero h1 {
  font-size: 2.6rem;
  font-weight: 800;
  color: var(--slate-900);
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 16px;
}

.page-hero .lead {
  font-size: 1.1rem;
  color: var(--slate-500);
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ---- download table ---- */
.dl-table-wrap {
  overflow-x: auto;
  margin-top: 40px;
}

.dl-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.dl-table thead th {
  background: var(--slate-50);
  padding: 16px 20px;
  text-align: left;
  font-weight: 600;
  color: var(--slate-600);
  border-bottom: 2px solid var(--slate-200);
  white-space: nowrap;
}

.dl-table tbody td {
  padding: 16px 20px;
  border-bottom: 1px solid var(--slate-100);
  color: var(--slate-700);
}

.dl-table tbody tr:hover {
  background: var(--slate-50);
}

.dl-table .platform-cell {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  color: var(--slate-900);
}

.dl-table .platform-cell i {
  color: var(--brand);
  font-size: 1.2rem;
  width: 24px;
  text-align: center;
}

.badge-ver {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 0.78rem;
  font-weight: 600;
  background: var(--brand-light);
  color: var(--brand);
}

.badge-new {
  background: #d1fae5;
  color: var(--accent-dark);
}

/* ---- accordion / faq ---- */
.faq-list {
  margin-top: 40px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-item {
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.faq-q {
  width: 100%;
  background: none;
  border: none;
  padding: 20px 24px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--slate-800);
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: inherit;
}

.faq-q:hover {
  background: var(--slate-50);
}

.faq-a {
  padding: 0 24px 20px;
  font-size: 0.93rem;
  color: var(--slate-600);
  line-height: 1.7;
  display: none;
}

.faq-item.open .faq-a {
  display: block;
}

.faq-item.open .faq-q i {
  transform: rotate(180deg);
}

.faq-q i {
  transition: transform var(--duration) var(--ease-out);
  color: var(--slate-400);
}

/* ---- article content ---- */
.article-body {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--slate-700);
}

.article-body h2 {
  font-size: 1.65rem;
  font-weight: 700;
  color: var(--slate-900);
  margin-top: 44px;
  margin-bottom: 18px;
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--slate-900);
  margin-top: 32px;
  margin-bottom: 14px;
}

.article-body p {
  margin-bottom: 18px;
}

.article-body ul,
.article-body ol {
  margin-bottom: 20px;
  padding-left: 24px;
}

.article-body li {
  margin-bottom: 8px;
}

.article-body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  margin: 24px 0;
}

.article-body blockquote {
  border-left: 4px solid var(--brand);
  padding: 16px 24px;
  margin: 28px 0;
  background: var(--brand-light);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-style: italic;
  color: var(--slate-600);
}

.article-body .info-callout {
  background: #fffbeb;
  border-left: 4px solid var(--warn);
  padding: 20px;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin: 24px 0;
}

.article-body .info-callout strong {
  color: #92400e;
}

/* ---- comparison table ---- */
.cmp-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 32px;
  font-size: 0.93rem;
}

.cmp-table th,
.cmp-table td {
  padding: 14px 18px;
  border: 1px solid var(--slate-200);
}

.cmp-table thead th {
  background: var(--slate-900);
  color: var(--white);
  font-weight: 600;
  text-align: center;
}

.cmp-table thead th:first-child {
  text-align: left;
  background: var(--slate-50);
  color: var(--slate-700);
  border-bottom-color: var(--slate-200);
}

.cmp-table tbody td:first-child {
  font-weight: 600;
  background: var(--slate-50);
}

.cmp-table tbody td {
  text-align: center;
  color: var(--slate-600);
}

.cmp-table .check {
  color: var(--accent);
  font-weight: 700;
}

.cmp-table .dash {
  color: var(--slate-300);
}

/* ---- AI page ---- */
.ai-highlight {
  background: linear-gradient(135deg, #1e1b4b 0%, #312e81 50%, #1e3a5f 100%);
  border-radius: var(--radius-lg);
  padding: 56px;
  color: var(--white);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}

.ai-highlight h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 14px;
}

.ai-highlight p {
  opacity: 0.85;
  line-height: 1.7;
}

.ai-features {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-top: 48px;
}

.ai-card {
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-md);
  padding: 32px;
  transition: all var(--duration) var(--ease-out);
}

.ai-card:hover {
  border-color: #7c3aed;
  box-shadow: 0 0 0 4px rgba(124,58,237,0.08);
}

.ai-card .ai-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background: #f5f3ff;
  color: #7c3aed;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.35rem;
  margin-bottom: 18px;
}

/* ---- breadcrumb ---- */
.breadcrumb {
  padding: 16px 0;
  font-size: 0.88rem;
  color: var(--slate-400);
}

.breadcrumb a {
  color: var(--slate-500);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--brand);
}

.breadcrumb span {
  margin: 0 8px;
}

/* ---- footer ---- */
.site-footer {
  background: var(--slate-900);
  color: var(--slate-400);
  padding: 72px 0 0;
  margin-top: 40px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 44px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-about img {
  width: 36px;
  height: 36px;
  object-fit: contain;
}

.footer-about .f-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.footer-about .f-brand span {
  color: var(--white);
  font-size: 1.2rem;
  font-weight: 700;
}

.footer-about p {
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--slate-400);
}

.footer-col h4 {
  color: var(--white);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 18px;
}

.footer-col ul {
  list-style: none;
}

.footer-col li {
  margin-bottom: 10px;
}

.footer-col a {
  color: var(--slate-400);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 180ms;
}

.footer-col a:hover {
  color: var(--white);
}

.footer-base {
  padding: 22px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.84rem;
  color: var(--slate-500);
}

.footer-base a {
  color: var(--slate-400);
  text-decoration: none;
}

.footer-base a:hover {
  color: var(--white);
}

/* ---- responsive ---- */
@media (max-width: 1024px) {
  .hero-grid,
  .two-col,
  .ai-highlight {
    grid-template-columns: 1fr;
  }

  .features-grid,
  .ai-features {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .trust-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero-title {
    font-size: 2.3rem;
  }

  .two-col--rtl .two-col-text {
    order: 0;
  }
}

@media (max-width: 768px) {
  .main-nav {
    display: none;
  }

  .features-grid,
  .ai-features,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .trust-grid {
    grid-template-columns: 1fr 1fr;
  }

  section {
    padding: 56px 0;
  }

  .hero {
    padding: 64px 0 56px;
  }

  .hero-title {
    font-size: 1.85rem;
  }

  .section-title {
    font-size: 1.65rem;
  }

  .page-hero h1 {
    font-size: 1.8rem;
  }

  .btn {
    padding: 11px 22px;
    font-size: 0.95rem;
  }

  .footer-base {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .hero-actions {
    flex-direction: column;
  }

  .hero-actions .btn {
    width: 100%;
    justify-content: center;
  }

  .trust-grid {
    grid-template-columns: 1fr;
  }
}