:root {
  --bg: #0f1419;
  --surface: #1a2332;
  --border: #2d3a4f;
  --text: #e7ecf3;
  --muted: #8b9cb3;
  --accent: #3b82f6;
  --code: #0d1117;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 15px;
  padding-bottom: 2rem;
}

.wrap {
  max-width: 920px;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
  padding-left: max(1.25rem, 5.5rem);
}

.page-section {
  scroll-margin-top: 1.25rem;
}

.page-section + .page-section {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.section-nav {
  position: fixed;
  top: 50%;
  left: max(0.65rem, env(safe-area-inset-left));
  transform: translateY(-50%);
  z-index: 1001;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding: 0.45rem;
  background: rgba(26, 35, 50, 0.92);
  border: 1px solid var(--border);
  border-radius: 10px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
  backdrop-filter: blur(8px);
}

.section-nav-btn {
  display: block;
  padding: 0.45rem 0.65rem;
  font-size: 0.72rem;
  font-weight: 600;
  line-height: 1.25;
  text-align: center;
  text-decoration: none;
  color: var(--muted);
  border-radius: 6px;
  transition: background 0.15s, color 0.15s;
  max-width: 5.5rem;
}

.section-nav-btn:hover {
  color: var(--text);
  background: rgba(59, 130, 246, 0.15);
}

.section-nav-btn.is-active {
  color: #fff;
  background: var(--accent);
}

.guide-title {
  font-size: 1.35rem;
  margin-top: 0;
}

.guide-intro {
  margin-bottom: 1.25rem;
}

.guide-card {
  background: rgba(26, 35, 50, 0.45);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.1rem 0.5rem;
  margin: 1.25rem 0;
}

.guide-card h3 {
  margin: 0 0 0.65rem;
  font-size: 1.05rem;
  color: var(--text);
}

ol.steps {
  margin: 0 0 0.85rem;
  padding-left: 1.25rem;
  color: var(--muted);
  font-size: 0.92rem;
}

ol.steps li {
  margin: 0.25rem 0;
}

.page-meta {
  margin-top: 2rem;
  color: var(--muted);
  font-size: 0.85rem;
}

@media (max-width: 720px) {
  .wrap {
    padding-left: 1.25rem;
    padding-top: 3.5rem;
  }

  .section-nav {
    top: 0.65rem;
    left: 50%;
    right: auto;
    transform: translateX(-50%);
    flex-direction: row;
    width: calc(100% - 5rem);
    max-width: 320px;
  }

  .section-nav-btn {
    flex: 1;
    max-width: none;
    font-size: 0.78rem;
  }
}

h1 {
  font-size: 1.7rem;
  margin: 0 0 0.5rem;
}

h2 {
  font-size: 1.2rem;
  margin: 2rem 0 0.6rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--border);
}

p,
li {
  color: var(--muted);
}

code {
  font-family: ui-monospace, monospace;
  color: #f472b6;
  font-size: 0.9em;
}

pre {
  background: var(--code);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.85rem 1rem;
  overflow-x: auto;
  font-size: 0.82rem;
  line-height: 1.45;
}

pre.copyable {
  cursor: pointer;
  position: relative;
  padding-top: 1.75rem;
  transition: border-color 0.15s, box-shadow 0.15s;
}

pre.copyable:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px rgba(59, 130, 246, 0.25);
}

pre.copyable::before {
  content: "Click để copy";
  position: absolute;
  top: 0.45rem;
  right: 0.75rem;
  font-size: 0.68rem;
  color: var(--muted);
  font-family: system-ui, sans-serif;
}

pre code {
  color: #e2e8f0;
  pointer-events: none;
}

.note {
  border-left: 3px solid #f59e0b;
  padding: 0.6rem 0.9rem;
  background: #1c1910;
  border-radius: 0 6px 6px 0;
  margin: 1rem 0;
  color: var(--muted);
}

.note strong {
  color: var(--text);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  margin: 1rem 0;
}

th,
td {
  text-align: left;
  padding: 0.5rem 0.6rem;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

th {
  color: #94a3b8;
  font-size: 0.75rem;
  text-transform: uppercase;
}

ul.compact {
  margin: 0.4rem 0;
  padding-left: 1.25rem;
}

a {
  color: var(--accent);
}

.site-footer {
  position: fixed;
  bottom: 1rem;
  right: 1rem;
  left: auto;
  z-index: 1000;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.45rem;
  padding: 0;
}

.contact-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border-radius: 50%;
  text-decoration: none;
  border: 1px solid rgba(255, 255, 255, 0.12);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.35);
  transition: transform 0.15s, box-shadow 0.15s, filter 0.15s;
}

.contact-btn svg {
  width: 22px;
  height: 22px;
  fill: currentColor;
  pointer-events: none;
}

.contact-btn:hover {
  transform: translateY(-2px) scale(1.05);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.45);
  filter: brightness(1.1);
}

.contact-btn.zalo {
  background: #0068ff;
  color: #fff;
}

.contact-btn.telegram {
  background: #229ed9;
  color: #fff;
}

.contact-btn.facebook {
  background: #1877f2;
  color: #fff;
}

@keyframes wiggle {
  0%,
  100% {
    transform: rotate(0) translateY(0);
  }
  15% {
    transform: rotate(-1.2deg) translateY(-1px);
  }
  30% {
    transform: rotate(1.2deg) translateY(-1px);
  }
  45% {
    transform: rotate(-1deg);
  }
  60% {
    transform: rotate(1deg);
  }
  75%,
  100% {
    transform: rotate(0) translateY(0);
  }
}

.contact-btn.wiggle {
  animation: wiggle 2.8s ease-in-out infinite;
}

.contact-btn.wiggle.d2 {
  animation-delay: 0.35s;
}

.contact-btn.wiggle.d3 {
  animation-delay: 0.7s;
}

@media (prefers-reduced-motion: reduce) {
  .contact-btn.wiggle {
    animation: none;
  }
}

.toast {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%) translateY(120%);
  background: #1e293b;
  color: #f1f5f9;
  border: 1px solid var(--border);
  padding: 0.65rem 1.15rem;
  border-radius: 8px;
  font-size: 0.9rem;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
  z-index: 9999;
  opacity: 0;
  transition: transform 0.25s ease, opacity 0.25s ease;
  pointer-events: none;
}

.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}