:root {
  --accent: #dc3527; /* Guaranteed >4.5:1 contrast on #f4f4f6 */
  --accent-dark: #c02d22;
  --accent-light: rgba(232, 55, 42, 0.08);
  --accent-glow: rgba(232, 55, 42, 0.18);
  --bg: #fff;
  --bg-2: #f7f7f8;
  --bg-3: #ededf0;
  --surface: #fff;
  --surface-2: #f4f4f6;
  --border: #e2e2e6;
  --border-light: #ececef;
  --t1: #0d0d10;
  --t2: #48485a;
  --t3: #5f5f6e; /* Improved contrast from #88889a */
  --sh-sm: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --sh-md: 0 4px 14px rgba(0, 0, 0, 0.08), 0 2px 4px rgba(0, 0, 0, 0.04);
  --sh-lg: 0 10px 32px rgba(0, 0, 0, 0.1), 0 4px 8px rgba(0, 0, 0, 0.05);
  --sh-xl: 0 20px 52px rgba(0, 0, 0, 0.12), 0 8px 16px rgba(0, 0, 0, 0.06);
  --r-xs: 4px;
  --r-sm: 8px;
  --r-md: 12px;
  --r-lg: 18px;
  --r-xl: 26px;
  --r-full: 9999px;
  --fh: "Sora", sans-serif;
  --fb: "DM Sans", sans-serif;
  --fm: "Courier New", Courier, monospace;
  --nav-h: 68px;
  --wide-w: 1140px;
  --sb-w: 290px;
  --tr: 0.22s ease;
}
[data-theme="dark"] {
  --bg: #0b0b0e;
  --bg-2: #131318;
  --bg-3: #1c1c23;
  --surface: #16161d;
  --surface-2: #1d1d26;
  --border: #28283a;
  --border-light: #202030;
  --t1: #ededf2;
  --t2: #9898ae;
  --t3: #5a5a72;
  --sh-sm: 0 1px 3px rgba(0, 0, 0, 0.35);
  --sh-md: 0 4px 14px rgba(0, 0, 0, 0.45);
  --sh-lg: 0 10px 32px rgba(0, 0, 0, 0.55);
  --sh-xl: 0 20px 52px rgba(0, 0, 0, 0.65);
}
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  scroll-behavior: smooth;
  font-size: 16px;
}
body {
  font-family: var(--fb);
  background: var(--bg);
  color: var(--t1);
  line-height: 1.7;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition:
    background var(--tr),
    color var(--tr);
  overflow-x: hidden;
}
a {
  color: inherit;
  text-decoration: none;
}
img {
  max-width: 100%;
  display: block;
}
button {
  cursor: pointer;
  font-family: var(--fb);
  border: none;
  background: none;
}
.skip {
  position: absolute;
  top: -99px;
  left: 16px;
  background: var(--accent);
  color: #fff;
  padding: 8px 16px;
  border-radius: var(--r-sm);
  font-size: 0.875rem;
  font-weight: 600;
  z-index: 9999;
  transition: top 0.2s;
}
.skip:focus {
  top: 8px;
}
.rbar {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  background: var(--accent);
  width: 0%;
  z-index: 2000;
  transition: width 0.12s;
}
/* Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--nav-h);
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--sh-sm);
  transition:
    background var(--tr),
    border-color var(--tr);
}
.nav-inner {
  max-width: var(--wide-w);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.nav-logo img {
  width: 36px;
  height: 36px;
  aspect-ratio: 1 / 1;
  border-radius: var(--r-sm);
}
.nav-logo-text {
  font-family: var(--fh);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--t1);
  letter-spacing: -0.02em;
}
.nav-logo-text span {
  color: var(--accent);
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 2px;
  list-style: none;
  margin: 0 auto;
}
.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--t2);
  padding: 7px 13px;
  border-radius: var(--r-sm);
  transition:
    color var(--tr),
    background var(--tr);
  white-space: nowrap;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
  background: var(--accent-light);
}
.nav-right {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}
.btn-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--r-sm);
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--t2);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--tr);
  flex-shrink: 0;
}
.btn-icon:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-light);
}
.btn-icon svg {
  width: 18px;
  height: 18px;
  pointer-events: none;
}
.icon-sun {
  display: none;
}
.icon-moon {
  display: block;
}
[data-theme="dark"] .icon-sun {
  display: block;
}
[data-theme="dark"] .icon-moon {
  display: none;
}
.btn-primary {
  font-size: 0.85rem;
  font-weight: 600;
  padding: 9px 20px;
  background: var(--accent);
  color: #fff;
  border-radius: var(--r-full);
  transition:
    background var(--tr),
    transform var(--tr),
    box-shadow var(--tr);
  white-space: nowrap;
}
.btn-primary:hover {
  background: var(--accent-dark);
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(232, 55, 42, 0.35);
}
.nav-hamburger {
  display: none;
}
/* Drawer */
.drawer-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.52);
  z-index: 1900;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s;
}
.drawer-overlay.open {
  opacity: 1;
  pointer-events: all;
}
.mobile-drawer {
  position: fixed;
  top: 0;
  right: -100%;
  width: min(320px, 92vw);
  height: 100dvh;
  background: var(--surface);
  border-left: 1px solid var(--border);
  box-shadow: var(--sh-xl);
  z-index: 2000;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  transition: right 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.mobile-drawer.open {
  right: 0;
}
.drawer-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 20px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}
.drawer-nav {
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex: 1;
}
.drawer-nav a {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--t2);
  padding: 12px 14px;
  border-radius: var(--r-md);
  transition:
    color var(--tr),
    background var(--tr);
}
.drawer-nav a svg {
  width: 17px;
  height: 17px;
  flex-shrink: 0;
}
.drawer-nav a:hover {
  color: var(--accent);
  background: var(--accent-light);
}
.drawer-foot {
  padding: 16px 20px;
  border-top: 1px solid var(--border);
}
.drawer-foot a {
  display: block;
  text-align: center;
  padding: 13px;
  background: var(--accent);
  color: #fff;
  border-radius: var(--r-md);
  font-weight: 600;
  font-size: 0.9rem;
  transition: background var(--tr);
}
.drawer-foot a:hover {
  background: var(--accent-dark);
}
/* Breadcrumb */
.bc-bar {
  background: var(--bg-2);
  border-bottom: 1px solid var(--border-light);
}
.bc-inner {
  max-width: var(--wide-w);
  margin: 0 auto;
  padding: 12px 24px;
}
.bc {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  font-size: 0.8rem;
  color: var(--t3);
}
.bc a {
  transition: color var(--tr);
}
.bc a:hover {
  color: var(--accent);
}
.bc svg {
  width: 11px;
  height: 11px;
  flex-shrink: 0;
  opacity: 0.45;
}
.bc span {
  color: var(--t2);
  font-weight: 500;
}
/* Hero */
.hero {
  max-width: 780px;
  margin: 0 auto;
  padding: 56px 24px 44px;
}
.blog-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-light);
  border: 1px solid rgba(232, 55, 42, 0.18);
  padding: 5px 13px;
  border-radius: var(--r-full);
  margin-bottom: 22px;
}
.blog-tag svg {
  width: 12px;
  height: 12px;
}
.blog-title {
  font-family: var(--fh);
  font-size: clamp(1.75rem, 4.2vw, 2.8rem);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.035em;
  color: var(--t1);
  margin-bottom: 20px;
}
.blog-title .hl {
  color: var(--accent);
}
.blog-lede {
  font-size: 1.08rem;
  color: var(--t2);
  line-height: 1.72;
  margin-bottom: 28px;
  max-width: 660px;
}
.blog-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 18px;
  padding: 18px 0;
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}
.meta-pill {
  display: flex;
  align-items: center;
  gap: 7px;
  font-size: 0.82rem;
  color: var(--t3);
}
.meta-pill svg {
  width: 13px;
  height: 13px;
}
.meta-pill strong {
  color: var(--t2);
  font-weight: 500;
}
/* Mobile TOC */
.mtoc {
  display: none;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  overflow: hidden;
  margin-bottom: 32px;
}
.mtoc-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 18px;
  background: var(--surface-2);
  font-family: var(--fh);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--t1);
  border: none;
  cursor: pointer;
  transition: background var(--tr);
}
.mtoc-toggle:hover {
  background: var(--accent-light);
}
.mtoc-toggle svg {
  width: 18px;
  height: 18px;
  transition: transform 0.28s;
  flex-shrink: 0;
}
.mtoc-toggle .ti {
  color: var(--accent);
}
.mtoc-toggle .ch {
  color: var(--t3);
}
.mtoc-toggle-inner {
  display: flex;
  align-items: center;
  gap: 8px;
}
.mtoc.open .mtoc-toggle .ch {
  transform: rotate(180deg);
}
.mtoc-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}
.mtoc.open .mtoc-body {
  max-height: 700px;
}
.mtoc-list {
  list-style: none;
  padding: 8px 0 12px;
}
.mtoc-list li a {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 8px 18px;
  font-size: 0.85rem;
  color: var(--t2);
  transition:
    color var(--tr),
    background var(--tr);
}
.mtoc-list li a:hover {
  color: var(--accent);
  background: var(--accent-light);
}
.mtoc-list li a .tn {
  flex-shrink: 0;
  font-family: var(--fh);
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--accent);
  background: var(--accent-light);
  border-radius: var(--r-full);
  min-width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 5px;
  margin-top: 1px;
}
/* Layout */
.page-layout {
  max-width: var(--wide-w);
  margin: 0 auto;
  padding: 0 24px 96px;
  display: grid;
  grid-template-columns: 1fr var(--sb-w);
  gap: 52px;
  align-items: start;
}
.article-body {
  min-width: 0;
}
/* Typography */
.article-body h2 {
  font-family: var(--fh);
  font-size: clamp(1.3rem, 2.5vw, 1.65rem);
  font-weight: 700;
  letter-spacing: -0.025em;
  color: var(--t1);
  margin: 60px 0 16px;
  padding-top: 60px;
  border-top: 1px solid var(--border-light);
  scroll-margin-top: calc(var(--nav-h) + 24px);
  line-height: 1.3;
}
.article-body h2:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}
.article-body h3 {
  font-family: var(--fh);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--t1);
  margin: 36px 0 12px;
  scroll-margin-top: calc(var(--nav-h) + 24px);
}
.article-body h4 {
  font-family: var(--fh);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--t1);
  margin: 24px 0 8px;
}
.article-body p {
  color: var(--t2);
  margin-bottom: 18px;
  font-size: 0.975rem;
  line-height: 1.78;
}
.article-body ul,
.article-body ol {
  color: var(--t2);
  margin-bottom: 20px;
  font-size: 0.975rem;
  padding-left: 1.5rem;
}
.article-body li {
  margin-bottom: 9px;
  line-height: 1.68;
}
.article-body strong {
  color: var(--t1);
  font-weight: 600;
}
.article-body code {
  font-family: var(--fm);
  font-size: 0.855em;
  background: var(--bg-3);
  border: 1px solid var(--border);
  padding: 2px 7px;
  border-radius: var(--r-xs);
  color: var(--accent);
  word-break: break-all;
}
.article-body a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: opacity var(--tr);
}
.article-body a:hover {
  opacity: 0.72;
}
.article-body kbd {
  font-family: var(--fm);
  font-size: 0.82em;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  padding: 1px 6px;
  border-radius: var(--r-xs);
  color: var(--t1);
}
/* Callouts */
.callout {
  display: flex;
  gap: 14px;
  padding: 18px 20px;
  border-radius: var(--r-md);
  margin: 28px 0;
}
.callout-icon {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  margin-top: 1px;
}
.callout-body {
  font-size: 0.925rem;
  color: var(--t2);
  line-height: 1.68;
}
.callout-body strong {
  display: block;
  margin-bottom: 5px;
  font-size: 0.95rem;
  color: var(--t1);
}
.c-info {
  background: var(--accent-light);
  border: 1px solid rgba(232, 55, 42, 0.18);
  border-left: 4px solid var(--accent);
}
.c-info .callout-icon {
  color: var(--accent);
}
.c-warn {
  background: rgba(245, 158, 11, 0.07);
  border: 1px solid rgba(245, 158, 11, 0.22);
  border-left: 4px solid #f59e0b;
}
.c-warn .callout-icon {
  color: #f59e0b;
}
.c-ok {
  background: rgba(34, 197, 94, 0.07);
  border: 1px solid rgba(34, 197, 94, 0.22);
  border-left: 4px solid #22c55e;
}
.c-ok .callout-icon {
  color: #22c55e;
}
.c-neutral {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-left: 4px solid var(--t3);
}
.c-neutral .callout-icon {
  color: var(--t3);
}
/* Tables */
.tbl-wrap {
  overflow-x: auto;
  margin: 24px 0;
  border-radius: var(--r-md);
  border: 1px solid var(--border);
  -webkit-overflow-scrolling: touch;
}
.dtable {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  min-width: 480px;
}
.dtable th {
  background: var(--bg-3);
  color: var(--t1);
  font-family: var(--fh);
  font-weight: 600;
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
.dtable td {
  padding: 12px 16px;
  color: var(--t2);
  border-bottom: 1px solid var(--border-light);
  vertical-align: top;
  line-height: 1.55;
}
.dtable tr:last-child td {
  border-bottom: none;
}
.dtable tr:nth-child(even) td {
  background: var(--bg-2);
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.74rem;
  font-weight: 600;
  padding: 3px 9px;
  border-radius: var(--r-full);
  white-space: nowrap;
}
.bg {
  background: rgba(34, 197, 94, 0.1);
  color: #117034; /* Darker green for contrast */
}
.br {
  background: rgba(239, 68, 68, 0.1);
  color: #b91c1c; /* Darker red for contrast */
}
.bb {
  background: rgba(59, 130, 246, 0.1);
  color: #1d4ed8; /* Darker blue for contrast */
}
.bo {
  background: rgba(245, 158, 11, 0.1);
  color: #92400e; /* Darker orange for contrast */
}
[data-theme="dark"] .bg {
  background: rgba(34, 197, 94, 0.15);
  color: #4ade80;
}
[data-theme="dark"] .br {
  background: rgba(239, 68, 68, 0.15);
  color: #f87171;
}
[data-theme="dark"] .bb {
  background: rgba(59, 130, 246, 0.15);
  color: #60a5fa;
}
[data-theme="dark"] .bo {
  background: rgba(245, 158, 11, 0.15);
  color: #fbbf24;
}
/* Steps */
.steps {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin: 24px 0;
}
.scard {
  display: flex;
  gap: 16px;
  padding: 18px 20px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  transition:
    border-color var(--tr),
    box-shadow var(--tr);
}
.scard:hover {
  border-color: var(--accent);
  box-shadow: var(--sh-md);
}
.snum {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: var(--r-full);
  background: var(--accent);
  color: #fff;
  font-family: var(--fh);
  font-size: 0.8rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 1px;
}
.sbody h4 {
  font-family: var(--fh);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--t1);
  margin-bottom: 6px;
}
.sbody p {
  font-size: 0.88rem;
  color: var(--t2);
  margin: 0;
  line-height: 1.65;
}
/* Experiments */
.exp {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-xl);
  overflow: hidden;
  margin: 32px 0;
}
.exp-hdr {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 24px;
  background: var(--bg-3);
  border-bottom: 1px solid var(--border);
}
.exp-ico {
  width: 40px;
  height: 40px;
  border-radius: var(--r-md);
  background: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.exp-ico svg {
  width: 20px;
  height: 20px;
  color: #fff;
}
.exp-lbl {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 3px;
}
.exp-title {
  font-family: var(--fh);
  font-size: 1rem;
  font-weight: 700;
  color: var(--t1);
}
.exp-body {
  padding: 20px 24px;
}
.exp-body p {
  font-size: 0.925rem;
  margin-bottom: 14px;
  color: var(--t2);
  line-height: 1.7;
}
.exp-body p:last-child {
  margin-bottom: 0;
}
/* Bar chart */
.bchart {
  margin: 16px 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.brow {
  display: flex;
  flex-direction: column;
  gap: 5px;
}
.blbl {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--t2);
}
.blbl .bn {
  font-weight: 500;
  color: var(--t1);
}
.blbl .bv {
  font-family: var(--fm);
  font-size: 0.78rem;
  color: var(--accent);
}
.btrack {
  height: 9px;
  background: var(--bg-3);
  border-radius: var(--r-full);
  overflow: hidden;
}
.bfill {
  height: 100%;
  border-radius: var(--r-full);
  background: var(--accent);
  width: 0;
  transition: width 1.1s cubic-bezier(0.4, 0, 0.2, 1);
}
/* Stat cards */
.sgrid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 20px 0;
}
.scard2 {
  padding: 18px 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  text-align: center;
}
.sval {
  font-family: var(--fh);
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--accent);
  line-height: 1.1;
  margin-bottom: 6px;
}
.slbl {
  font-size: 0.78rem;
  color: var(--t3);
  line-height: 1.5;
}
/* Device comparison grid */
.device-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
  margin: 24px 0;
}
.device-card {
  padding: 16px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  transition: border-color var(--tr);
}
.device-card:hover {
  border-color: var(--accent);
}
.device-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--r-sm);
  background: var(--accent-light);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 10px;
}
.device-icon svg {
  width: 18px;
  height: 18px;
  color: var(--accent);
}
.device-name {
  font-family: var(--fh);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--t1);
  margin-bottom: 4px;
}
.device-browser {
  font-size: 0.76rem;
  color: var(--t3);
  margin-bottom: 8px;
}
.device-time {
  font-family: var(--fm);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--accent);
}
.device-label {
  font-size: 0.72rem;
  color: var(--t3);
}
/* Platform comparison */
.platform-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 24px 0;
}
.platform-card {
  padding: 20px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  transition: border-color var(--tr);
}
.platform-card:hover {
  border-color: var(--accent);
}
.platform-head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}
.platform-ico {
  width: 38px;
  height: 38px;
  border-radius: var(--r-md);
  background: var(--accent-light);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.platform-ico svg {
  width: 20px;
  height: 20px;
  color: var(--accent);
}
.platform-name {
  font-family: var(--fh);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--t1);
}
.platform-sub {
  font-size: 0.75rem;
  color: var(--t3);
}
.platform-card ul {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.platform-card ul li {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--t2);
  line-height: 1.5;
}
.platform-card ul li svg {
  flex-shrink: 0;
  width: 14px;
  height: 14px;
  color: var(--accent);
  margin-top: 2px;
}
/* Format support grid */
.fmt-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 10px;
  margin: 20px 0;
}
.fmt-card {
  padding: 14px 16px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  text-align: center;
  transition: border-color var(--tr);
}
.fmt-card:hover {
  border-color: var(--accent);
}
.fmt-ext {
  font-family: var(--fm);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 5px;
}
.fmt-name {
  font-size: 0.76rem;
  color: var(--t3);
  margin-bottom: 6px;
}
.fmt-support {
  display: flex;
  justify-content: center;
  gap: 4px;
  flex-wrap: wrap;
}
/* CTA banner */
.cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
  padding: 30px 32px;
  margin: 44px 0;
  background: linear-gradient(
    135deg,
    var(--accent) 0%,
    var(--accent-dark) 100%
  );
  border-radius: var(--r-xl);
  color: #fff;
}
.cta h3 {
  font-family: var(--fh);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 6px;
  color: #fff;
}
.cta p {
  font-size: 0.88rem;
  opacity: 0.88;
  margin: 0;
  color: #fff;
}
.cta-btn {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  background: #fff;
  color: var(--accent);
  border-radius: var(--r-full);
  font-weight: 700;
  font-size: 0.88rem;
  transition:
    transform var(--tr),
    box-shadow var(--tr);
  white-space: nowrap;
}
.cta-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.22);
}
.cta-btn svg {
  width: 15px;
  height: 15px;
}
/* FAQ */
.faqlist {
  margin: 24px 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.fitem {
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  overflow: hidden;
  transition: border-color var(--tr);
}
.fitem.open {
  border-color: var(--accent);
}
.fq {
  width: 100%;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 14px;
  padding: 16px 18px;
  background: var(--surface-2);
  text-align: left;
  font-family: var(--fh);
  font-size: 0.93rem;
  font-weight: 600;
  color: var(--t1);
  line-height: 1.4;
  transition:
    background var(--tr),
    color var(--tr);
}
.fitem.open .fq {
  background: var(--accent-light);
  color: var(--accent);
}
.fq svg {
  flex-shrink: 0;
  width: 18px;
  height: 18px;
  transition: transform 0.28s;
  margin-top: 2px;
}
.fitem.open .fq svg {
  transform: rotate(45deg);
}
.fa {
  max-height: 0;
  overflow: hidden;
  transition:
    max-height 0.35s cubic-bezier(0.4, 0, 0.2, 1),
    padding 0.25s;
  padding: 0 18px;
}
.fitem.open .fa {
  max-height: 800px;
  padding: 16px 18px;
}
.fa p {
  font-size: 0.9rem;
  color: var(--t2);
  margin: 0 0 10px;
  line-height: 1.72;
}
.fa p:last-child {
  margin-bottom: 0;
}
/* Sidebar */
.sidebar {
  position: sticky;
  top: calc(var(--nav-h) + 20px);
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.sbcard {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  overflow: hidden;
}
.sbhead {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  font-family: var(--fh);
  font-weight: 600;
  font-size: 0.83rem;
  color: var(--t1);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.sbhead svg {
  width: 15px;
  height: 15px;
  color: var(--accent);
}
.toclist {
  list-style: none;
  padding: 6px 0;
}
.toclist li a {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  padding: 8px 18px;
  font-size: 0.82rem;
  color: var(--t2);
  border-left: 2px solid transparent;
  line-height: 1.45;
  transition: all var(--tr);
}
.toclist li a:hover,
.toclist li a.ta {
  color: var(--accent);
  border-left-color: var(--accent);
  background: var(--accent-light);
}
.tdot {
  flex-shrink: 0;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: currentColor;
  margin-top: 7px;
}
.tprog {
  height: 3px;
  background: var(--bg-3);
  margin: 0 18px 14px;
  border-radius: var(--r-full);
  overflow: hidden;
}
.tprogbar {
  height: 100%;
  background: var(--accent);
  border-radius: var(--r-full);
  width: 0%;
  transition: width 0.2s;
}
.tlink {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 18px;
  border-bottom: 1px solid var(--border-light);
  transition: background var(--tr);
}
.tlink:last-child {
  border-bottom: none;
}
.tlink:hover {
  background: var(--accent-light);
}
.tico {
  width: 34px;
  height: 34px;
  border-radius: var(--r-sm);
  background: var(--accent-light);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.tico svg {
  width: 16px;
  height: 16px;
  color: var(--accent);
}
.tname {
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--t1);
  margin-bottom: 2px;
}
.tdesc {
  font-size: 0.74rem;
  color: var(--t3);
}
.sbcta {
  padding: 22px 20px;
  background: linear-gradient(
    135deg,
    var(--accent) 0%,
    var(--accent-dark) 100%
  );
  border-radius: var(--r-lg);
  text-align: center;
}
.sbcta-ico {
  display: flex;
  justify-content: center;
  margin-bottom: 10px;
}
.sbcta-ico svg {
  width: 30px;
  height: 30px;
  color: rgba(255, 255, 255, 0.8);
}
.sbcta h4 {
  font-family: var(--fh);
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 6px;
  color: #fff;
}
.sbcta p {
  font-size: 0.8rem;
  opacity: 0.88;
  margin-bottom: 16px;
  color: #fff;
  line-height: 1.55;
}
.sbcta a {
  display: block;
  padding: 10px;
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: #fff;
  border-radius: var(--r-md);
  font-weight: 600;
  font-size: 0.85rem;
  transition: background var(--tr);
}
.sbcta a:hover {
  background: rgba(255, 255, 255, 0.25);
}
/* Footer */
.footer {
  background: var(--bg-2);
  border-top: 1px solid var(--border);
  padding: 56px 24px 32px;
}
.footer-grid {
  max-width: var(--wide-w);
  margin: 0 auto 40px;
  display: grid;
  grid-template-columns: 1.8fr 1fr 1fr 1fr;
  gap: 40px;
}
.flogrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}
.flogrow img {
  width: 32px;
  height: 32px;
  border-radius: var(--r-sm);
}
.flogrow span {
  font-family: var(--fh);
  font-weight: 700;
  font-size: 1rem;
  color: var(--t1);
}
.flogrow span b {
  color: var(--accent);
}
.ftag {
  font-size: 0.83rem;
  color: var(--t3);
  line-height: 1.6;
  max-width: 240px;
}
.fct {
  font-family: var(--fh);
  font-weight: 600;
  font-size: 0.78rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--t1);
  margin-bottom: 14px;
}
.flinks {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 9px;
}
.flinks a {
  font-size: 0.84rem;
  color: var(--t3);
  transition: color var(--tr);
}
.flinks a:hover {
  color: var(--accent);
}
.fbot {
  max-width: var(--wide-w);
  margin: 0 auto;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}
.fcopy {
  font-size: 0.79rem;
  color: var(--t3);
}
.fcopy a {
  color: var(--accent);
}
/* Back to top */
.btt {
  position: fixed;
  bottom: 28px;
  right: 28px;
  width: 44px;
  height: 44px;
  border-radius: var(--r-full);
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--sh-lg);
  opacity: 0;
  pointer-events: none;
  transform: translateY(12px);
  transition:
    opacity var(--tr),
    transform var(--tr);
  z-index: 500;
}
.btt.vis {
  opacity: 1;
  pointer-events: all;
  transform: translateY(0);
}
.btt:hover {
  background: var(--accent-dark);
}
.btt svg {
  width: 18px;
  height: 18px;
}
.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition:
    opacity 0.55s ease,
    transform 0.55s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Performance Optimization */
.exp,
.faqlist,
.footer,
.cta,
.sidebar,
.platform-row,
.steps {
  content-visibility: auto;
  contain-intrinsic-size: 1px 500px;
}

/* ============ MEDIA QUERIES ============ */
@media (max-width: 1140px) {
  :root {
    --sb-w: 260px;
  }
  .page-layout {
    gap: 36px;
  }
}
@media (max-width: 1024px) {
  .nav-links,
  .btn-primary {
    display: none;
  }
  .nav-hamburger {
    display: flex;
  }
  .page-layout {
    grid-template-columns: 1fr;
    gap: 0;
    padding: 0 20px 72px;
  }
  .sidebar {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    margin-top: 40px;
  }
  .sidebar .sbcard:first-child {
    display: none;
  }
  .sidebar .sbcta {
    grid-column: 1/-1;
  }
  .mtoc {
    display: block;
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}
@media (max-width: 768px) {
  :root {
    --nav-h: 60px;
  }
  .hero {
    padding: 36px 16px 28px;
  }
  .page-layout {
    padding: 0 16px 56px;
  }
  .sidebar {
    grid-template-columns: 1fr;
  }
  .platform-row {
    grid-template-columns: 1fr;
  }
  .sgrid {
    gap: 10px;
  }
  .sval {
    font-size: 1.3rem;
  }
  .device-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .fmt-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .cta {
    flex-direction: column;
    text-align: center;
    padding: 24px 20px;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  .exp-hdr {
    padding: 14px 18px;
  }
  .exp-body {
    padding: 16px 18px;
  }
  .nav-inner {
    padding: 0 16px;
  }
  .bc-inner {
    padding: 10px 16px;
  }
}
@media (max-width: 480px) {
  :root {
    --nav-h: 56px;
  }
  .nav-logo-text {
    font-size: 1rem;
  }
  .nav-inner {
    padding: 0 14px;
  }
  .hero {
    padding: 28px 14px 24px;
  }
  .blog-meta {
    gap: 10px;
  }
  .meta-pill {
    font-size: 0.76rem;
  }
  .page-layout {
    padding: 0 14px 48px;
  }
  .sgrid {
    gap: 8px;
  }
  .sval {
    font-size: 1.15rem;
  }
  .slbl {
    font-size: 0.7rem;
  }
  .device-grid {
    grid-template-columns: 1fr 1fr;
    gap: 10px;
  }
  .fmt-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .dtable {
    font-size: 0.82rem;
  }
  .dtable th {
    font-size: 0.72rem;
    padding: 10px 12px;
  }
  .dtable td {
    padding: 10px 12px;
  }
  .scard {
    padding: 14px 16px;
    gap: 12px;
  }
  .fbot {
    flex-direction: column;
    text-align: center;
    gap: 8px;
  }
  .btt {
    bottom: 18px;
    right: 16px;
    width: 40px;
    height: 40px;
  }
  .cta {
    border-radius: var(--r-lg);
    padding: 20px 18px;
  }
}
@media (max-width: 375px) {
  .blog-title {
    font-size: 1.55rem;
  }
  .blog-lede {
    font-size: 0.95rem;
  }
  .article-body h2 {
    font-size: 1.25rem;
  }
  .sgrid {
    gap: 6px;
  }
  .sval {
    font-size: 1.05rem;
  }
  .fmt-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .device-grid {
    grid-template-columns: 1fr;
  }
}
@media print {
  .navbar,
  .bc-bar,
  .sidebar,
  .btt,
  .rbar,
  .cta,
  .mtoc,
  .drawer-overlay,
  .mobile-drawer {
    display: none !important;
  }
  .page-layout {
    grid-template-columns: 1fr;
  }
  .hero {
    padding: 20px 0;
  }
  body {
    font-size: 13px;
  }
}