:root {
  --bg: #f7f7f9;
  --fg: #1f2933;
  --muted: #4b5563;
  --accent: #ea382b;
  --card: #ffffff;
  --border: #e5e7eb;
  --shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
  --radius: 12px;
  --sidebar-width: 280px;
  --font:
    -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "Segoe UI", Roboto, sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html {
  overflow-x: hidden;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -moz-text-size-adjust: 100%;
  text-size-adjust: 100%;
  width: 100%;
  max-width: 100%;
  font-size: 16px;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--fg);
  line-height: 1.7;
  overflow-x: hidden;
  width: 100%;
  max-width: 100%;
  min-width: 0;
  position: relative;
  -webkit-overflow-scrolling: touch;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img,
video,
iframe {
  max-width: 100%;
  height: auto;
  display: block;
}
table {
  width: 100%;
  max-width: 100%;
  display: block;
  overflow-x: auto;
}
pre,
code {
  max-width: 100%;
  overflow-x: auto;
  word-break: break-all;
}

a {
  color: var(--accent);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

header.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  background: #fff;
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
}

.brand {
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: 0.02em;
}
.brand a {
  color: var(--fg);
}
.brand a:hover {
  text-decoration: none;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0;
}
nav a {
  padding: 8px 14px;
  border-radius: 8px;
  color: var(--fg);
  font-weight: 600;
  font-size: 0.95rem;
}
nav a:hover {
  background: var(--border);
  text-decoration: none;
}
nav a.active {
  background: var(--accent);
  color: #fff;
}

.layout {
  display: flex;
  margin-top: 60px;
  min-height: calc(100vh - 60px);
  width: 100%;
  max-width: 100vw;
  overflow-x: hidden;
}

.sidebar {
  width: var(--sidebar-width);
  background: #fff;
  border-right: 1px solid var(--border);
  padding: 24px 16px;
  position: fixed;
  top: 60px;
  bottom: 0;
  overflow-y: auto;
}

.sidebar h4 {
  margin: 0 0 12px;
  font-size: 0.85rem;
  text-transform: uppercase;
  color: var(--muted);
  letter-spacing: 0.05em;
}

.sidebar ul {
  list-style: none;
  padding: 0;
  margin: 0 0 24px;
}
.sidebar li {
  margin-bottom: 6px;
}
.sidebar a {
  display: block;
  padding: 8px 12px;
  border-radius: 6px;
  color: var(--fg);
  font-weight: 500;
}
.sidebar a:hover {
  background: var(--border);
  text-decoration: none;
}
.sidebar a.active {
  background: var(--accent);
  color: #fff;
}

.content {
  margin-left: var(--sidebar-width);
  flex: 1;
  padding: 32px 40px 60px;
  max-width: 900px;
}

.content h1 {
  font-size: 2.2rem;
  margin: 0 0 16px;
  border-bottom: 2px solid var(--accent);
  padding-bottom: 12px;
}
.content h2 {
  font-size: 1.5rem;
  margin: 36px 0 16px;
  color: var(--accent);
}
.content h3 {
  font-size: 1.2rem;
  margin: 28px 0 12px;
}
.content p {
  margin: 0 0 16px;
}
.content ul,
.content ol {
  margin: 0 0 16px 24px;
}
.content li {
  margin-bottom: 8px;
}

pre.code-block {
  background: #0f172a;
  color: #e5e7eb;
  border-radius: 10px;
  padding: 16px 20px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 0.88rem;
  overflow-x: auto;
  margin: 0 0 20px;
  position: relative;
  white-space: pre-wrap;
  word-wrap: break-word;
  word-break: break-word;
  line-height: 1.5;
  max-width: 100%;
}

.copy-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  border: 1px solid #e5e7eb;
  background: rgba(255, 255, 255, 0.08);
  color: #e5e7eb;
  border-radius: 6px;
  padding: 6px 10px;
  font-size: 0.8rem;
  cursor: pointer;
}
.copy-btn:hover {
  background: rgba(255, 255, 255, 0.16);
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}

.card h3 {
  margin: 0 0 10px;
}
.card p {
  margin: 0;
  color: var(--muted);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(250px, 100%), 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.btn {
  display: inline-block;
  padding: 10px 16px;
  border-radius: 8px;
  font-weight: 700;
  border: 1px solid var(--accent);
  color: #fff;
  background: var(--accent);
  margin-right: 10px;
  margin-bottom: 10px;
}
.btn:hover {
  filter: brightness(0.95);
  text-decoration: none;
}
.btn.secondary {
  background: #fff;
  color: var(--accent);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 20px;
  display: block;
  overflow-x: auto;
  max-width: 100%;
}
th,
td {
  border: 1px solid var(--border);
  padding: 12px;
  text-align: left;
}
th {
  background: var(--border);
  font-weight: 600;
}

code {
  background: #e5e7eb;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 0.9em;
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--fg);
  cursor: pointer;
  padding: 8px;
}

.sidebar-toggle {
  display: none;
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 12px 16px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  width: 100%;
  text-align: left;
  margin-bottom: 16px;
  border-radius: 8px;
}

.sidebar-toggle i {
  margin-right: 8px;
}

.btn-row {
  margin-bottom: 24px;
}

.icon-accent {
  color: var(--accent);
}

.help-box {
  margin-top: 40px;
  padding: 20px;
  background: var(--card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.help-box h3 {
  margin-top: 0;
}
.help-box p {
  margin-bottom: 12px;
}

/* Tablet */
@media (max-width: 1024px) {
  .content {
    padding: 28px 24px 50px;
    max-width: 100%;
  }
  .content h1 {
    font-size: 1.8rem;
  }
  .content h2 {
    font-size: 1.3rem;
  }
  pre.code-block {
    font-size: 0.82rem;
    padding: 14px 16px;
  }
}

@media (max-width: 900px) {
  .sidebar {
    display: none;
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    z-index: 90;
    padding: 20px;
  }
  .sidebar.open {
    display: block;
  }
  .sidebar-toggle {
    display: block;
  }
  .content {
    margin-left: 0;
    padding: 24px 20px;
  }
  .feature-grid {
    grid-template-columns: 1fr;
  }
  table {
    font-size: 0.9rem;
  }
  th,
  td {
    padding: 10px 8px;
  }
}

@media (max-width: 640px) {
  .mobile-menu-btn {
    display: block;
  }
  header.topbar {
    flex-wrap: wrap;
    gap: 0;
    padding: 12px 16px;
  }
  .topbar-row {
    display: flex;
    width: 100%;
    justify-content: space-between;
    align-items: center;
  }
  nav {
    width: 100%;
    display: none;
    margin-top: 10px;
  }
  nav.open {
    display: block;
  }
  nav ul {
    flex-direction: column;
    gap: 4px;
  }
  nav a {
    display: block;
    padding: 10px 14px;
  }
  .content h1 {
    font-size: 1.5rem;
  }
  .content h2 {
    font-size: 1.15rem;
    margin: 28px 0 12px;
  }
  .content h3 {
    font-size: 1.05rem;
  }
  .content p,
  .content li {
    font-size: 0.95rem;
  }
  pre.code-block {
    font-size: 0.78rem;
    padding: 12px 14px;
  }
  .btn {
    padding: 10px 14px;
    font-size: 0.9rem;
    display: block;
    text-align: center;
    margin-right: 0;
  }
}

@media (max-width: 480px) {
  header.topbar {
    padding: 10px 12px;
  }
  .brand {
    font-size: 1rem;
  }
  .content {
    padding: 16px 14px;
  }
  .content h1 {
    font-size: 1.3rem;
    padding-bottom: 10px;
  }
  .content h2 {
    font-size: 1.1rem;
  }
  pre.code-block {
    font-size: 0.75rem;
    padding: 10px 12px;
    border-radius: 8px;
  }
  .card {
    padding: 14px;
  }
  table {
    font-size: 0.8rem;
  }
  th,
  td {
    padding: 8px 6px;
  }
}

/* iPhone Pro Max / Plus (428-430px) */
@media (max-width: 430px) {
  .content {
    padding: 16px 14px;
  }
  .content h1 {
    font-size: 1.35rem;
  }
  pre.code-block {
    font-size: 0.78rem;
  }
}

/* iPhone 14/15/16 Pro (393px) */
@media (max-width: 393px) {
  header.topbar {
    padding: 10px 12px;
  }
  .content {
    padding: 14px 12px;
  }
  .content h1 {
    font-size: 1.25rem;
  }
  .content h2 {
    font-size: 1.05rem;
  }
  pre.code-block {
    font-size: 0.72rem;
    padding: 10px;
  }
  .card {
    padding: 12px;
  }
}

/* iPhone 11/12/13/14 (390px) */
@media (max-width: 390px) {
  .content {
    padding: 12px 10px;
  }
  .content h1 {
    font-size: 1.2rem;
  }
  .btn {
    padding: 10px 12px;
    font-size: 0.85rem;
  }
}

/* iPhone SE / Mini (375px) */
@media (max-width: 375px) {
  header.topbar {
    padding: 8px 10px;
  }
  .brand {
    font-size: 0.92rem;
  }
  .content {
    padding: 10px 8px;
  }
  .content h1 {
    font-size: 1.15rem;
  }
  .content h2 {
    font-size: 1rem;
  }
  .content h3 {
    font-size: 0.95rem;
  }
  .content p,
  .content li {
    font-size: 0.88rem;
  }
  pre.code-block {
    font-size: 0.68rem;
    padding: 8px;
  }
  .card {
    padding: 10px;
  }
  .card h3 {
    font-size: 0.9rem;
  }
  table {
    font-size: 0.72rem;
  }
  th,
  td {
    padding: 6px 4px;
  }
  .help-box {
    padding: 14px;
  }
}

/* Extra small (320px) */
@media (max-width: 320px) {
  html {
    font-size: 14px;
  }
  .content {
    padding: 8px 6px;
  }
  .content h1 {
    font-size: 1.1rem;
  }
  pre.code-block {
    font-size: 0.65rem;
  }
}

/* Safe area insets for iPhone notch/Dynamic Island */
@supports (padding: max(0px)) {
  header.topbar {
    padding-left: max(12px, env(safe-area-inset-left));
    padding-right: max(12px, env(safe-area-inset-right));
    padding-top: max(10px, env(safe-area-inset-top));
  }
  .layout {
    margin-top: max(60px, calc(60px + env(safe-area-inset-top)));
  }
  .sidebar {
    top: max(60px, calc(60px + env(safe-area-inset-top)));
    padding-left: max(16px, env(safe-area-inset-left));
  }
  .content {
    padding-left: max(14px, env(safe-area-inset-left));
    padding-right: max(14px, env(safe-area-inset-right));
  }
}