/* ============================================================
   Blockchain 101 — design system
   Nền: dark tech · Accent duy nhất: emerald · Sans: Space Grotesk
   Radius: card 16px · button pill (quy tắc 1 thang đo)
   ============================================================ */

:root {
  --bg: #0a0d0c;
  --bg-soft: #0d1210;
  --panel: #101614;
  --panel-2: #141b18;
  --line: rgba(148, 190, 170, 0.14);
  --line-strong: rgba(148, 190, 170, 0.3);
  --text: #e7efea;
  --text-2: #c3d0c9;
  --muted: #8ba199;
  --accent: #3ddc97;
  --accent-ink: #04130c;
  --accent-dim: rgba(61, 220, 151, 0.12);
  --radius: 16px;
  --radius-sm: 6px;
  --font-sans:
    "Space Grotesk Variable", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono:
    "JetBrains Mono Variable", ui-monospace, "Cascadia Code", Consolas,
    monospace;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- Reset & base ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img {
  display: block;
  max-width: 100%;
}
a {
  color: inherit;
  text-decoration: none;
}
h1,
h2,
h3,
p,
dl,
dd,
figure,
blockquote,
ol {
  margin: 0;
}
ul,
ol {
  padding: 0;
}

::selection {
  background: var(--accent);
  color: var(--accent-ink);
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- Utilities ---------- */
.container {
  max-width: 1160px;
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 4vw, 2rem);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  clip-path: inset(50%);
  overflow: hidden;
  white-space: nowrap;
}

.hidden {
  display: none !important;
}

.skip-link {
  position: fixed;
  top: -60px;
  left: 1rem;
  z-index: 100;
  background: var(--accent);
  color: var(--accent-ink);
  padding: 0.5rem 1rem;
  border-radius: 8px;
  font-weight: 600;
  transition: top 0.2s var(--ease);
}
.skip-link:focus {
  top: 0.75rem;
}

/* ---------- Grain / noise overlay ---------- */
.grain {
  position: fixed;
  inset: 0;
  z-index: 90;
  pointer-events: none;
  opacity: 0.05;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ---------- Typography ---------- */
.hl {
  color: var(--accent);
  font-weight: 700;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.1rem;
}

.mono-tag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--muted);
  letter-spacing: 0.06em;
}

h1,
h2,
h3 {
  line-height: 1.12;
  letter-spacing: -0.02em;
  font-weight: 600;
  text-wrap: balance;
}

.section-title {
  font-size: clamp(1.7rem, 3.6vw, 2.5rem);
  max-width: 22ch;
  margin-bottom: 1rem;
}

.section-sub {
  color: var(--muted);
  max-width: 55ch;
  margin-bottom: clamp(2rem, 5vw, 3rem);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8rem 1.5rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  transition:
    transform 0.15s var(--ease),
    background 0.2s var(--ease),
    border-color 0.2s var(--ease),
    color 0.2s var(--ease);
}
.btn:active {
  transform: translateY(1px) scale(0.985);
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-ink);
}
.btn-primary:hover {
  background: #4fe5a4;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px -6px rgba(61, 220, 151, 0.4);
}

.btn-ghost {
  border-color: var(--line-strong);
  color: var(--text);
}
.btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
}

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text-2);
  padding: 0.8rem 0.1rem;
  border-bottom: 1px solid var(--line-strong);
  transition:
    color 0.2s var(--ease),
    border-color 0.2s var(--ease),
    gap 0.2s var(--ease);
}
.text-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  gap: 0.75rem;
}

/* ============================================================
   Header
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}
@supports not (backdrop-filter: blur(1px)) {
  .site-header {
    background: var(--bg);
  }
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  gap: 1.5rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
}
.brand-mark {
  width: 26px;
  height: 26px;
  color: var(--accent);
}
.brand-accent {
  color: var(--accent);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(1rem, 2.5vw, 2rem);
}

.nav-links a {
  font-size: 0.92rem;
  color: var(--text-2);
  padding: 0.35rem 0;
  position: relative;
  transition: color 0.2s var(--ease);
}
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 0;
  height: 1px;
  background: var(--accent);
  transition: right 0.25s var(--ease);
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
}
.nav-links a:hover::after,
.nav-links a.active::after {
  right: 0;
}
.nav-links a.active {
  color: var(--accent);
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--line-strong);
  color: var(--text);
  width: 42px;
  height: 42px;
  border-radius: 12px;
  font-size: 1.3rem;
  cursor: pointer;
}

/* ============================================================
   Hero
   ============================================================ */
.hero {
  position: relative;
  min-height: calc(100dvh - 68px);
  display: flex;
  align-items: center;
  padding-block: clamp(5rem, 12vh, 8rem);
  overflow: hidden;
}
/* lưới nền rất nhạt + quầng sáng accent */
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(rgba(148, 190, 170, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 190, 170, 0.05) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(
    ellipse 90% 70% at 65% 40%,
    #000 30%,
    transparent 75%
  );
}
.hero::after {
  content: "";
  position: absolute;
  pointer-events: none;
  width: 640px;
  height: 640px;
  right: -160px;
  top: -160px;
  background: radial-gradient(circle, rgba(61, 220, 151, 0.1), transparent 65%);
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
  width: 100%;
}

.hero-copy h1 {
  font-size: clamp(2.8rem, 6vw, 4.2rem);
  max-width: 14ch;
  line-height: 1.05;
  letter-spacing: -0.04em;
}

.hero-sub {
  margin-top: 1.25rem;
  color: var(--muted);
  max-width: 46ch;
  font-size: 1.05rem;
}

.hero-ctas {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-top: 2rem;
}

/* ---------- Specimen (poster sổ cái) ---------- */
.specimen {
  position: relative;
  padding: clamp(2rem, 4vw, 3rem);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius);
  background:
    linear-gradient(135deg, rgba(61, 220, 151, 0.08) 0%, transparent 100%),
    rgba(16, 22, 20, 0.7);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  box-shadow:
    0 40px 80px -30px rgba(4, 19, 12, 0.9),
    inset 0 1px 0 rgba(255, 255, 255, 0.1),
    inset 0 0 32px rgba(61, 220, 151, 0.03);
}

.specimen-block {
  background: rgba(10, 13, 12, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 12px;
  padding: 1.25rem;
  transition:
    transform 0.25s var(--ease),
    border-color 0.25s var(--ease),
    box-shadow 0.25s var(--ease);
  position: relative;
  z-index: 2;
}

.specimen-block:hover {
  transform: translateY(-2px);
  border-color: rgba(61, 220, 151, 0.3);
  box-shadow:
    0 10px 30px -10px rgba(0, 0, 0, 0.5),
    0 0 20px rgba(61, 220, 151, 0.05);
}

.specimen-block.highlight {
  border-color: rgba(61, 220, 151, 0.4);
  background: linear-gradient(
    145deg,
    rgba(10, 13, 12, 0.8),
    rgba(61, 220, 151, 0.05)
  );
  box-shadow: 0 0 30px rgba(61, 220, 151, 0.05) inset;
}

.specimen-block.dim {
  opacity: 0.6;
}

.block-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.block-title {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-2);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.block-badge {
  font-size: 0.65rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: rgba(61, 220, 151, 0.15);
  color: var(--accent);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  border: 1px solid rgba(61, 220, 151, 0.2);
}

.block-badge.dim {
  background: rgba(255, 255, 255, 0.05);
  color: var(--muted);
  border-color: rgba(255, 255, 255, 0.1);
}

.block-content {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.specimen-hash {
  font-family: var(--font-mono);
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  color: var(--text);
  word-break: break-all;
}
.specimen-hash.dim {
  color: var(--muted);
  font-size: clamp(1rem, 2vw, 1.3rem);
}

.specimen-sep {
  position: relative;
  height: 2.5rem;
  margin: 0 auto;
  width: 2px;
  background: linear-gradient(
    to bottom,
    rgba(61, 220, 151, 0.4),
    rgba(255, 255, 255, 0.1)
  );
  z-index: 1;
}
.specimen-sep::after {
  content: "↓";
  position: absolute;
  left: 50%;
  bottom: -0.6rem;
  transform: translateX(-50%);
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  background: var(--panel);
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
}

.specimen-note {
  margin-top: 2rem;
  padding-top: 1.25rem;
  border-top: 1px dashed rgba(255, 255, 255, 0.1);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--muted);
  text-align: center;
}

/* ============================================================
   Hệ sinh thái
   ============================================================ */
.ecosystem {
  padding-block: 2.5rem 3.5rem;
  border-top: 1px solid var(--line);
}

.ecosystem-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--muted);
  text-align: center;
  margin-bottom: 1.5rem;
}

.logo-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.25rem clamp(1.5rem, 5vw, 3.5rem);
  align-items: center;
}
.logo-row img {
  height: 22px;
  width: auto;
  opacity: 0.65;
  transition:
    opacity 0.25s var(--ease),
    transform 0.25s var(--ease);
}
.logo-row img:hover {
  opacity: 1;
  transform: translateY(-2px);
}

/* ============================================================
   Section chung
   ============================================================ */
.section {
  position: relative;
  overflow: hidden;
  padding-block: clamp(4.5rem, 9vw, 7rem);
}
.section-tint {
  background: var(--bg-soft);
}

/* ---------- Split (khái niệm) ---------- */
.split {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
}
.split-copy h2 {
  font-size: clamp(1.7rem, 3.6vw, 2.5rem);
  max-width: 18ch;
  margin-block: 0 1.25rem;
}
.split-copy > p {
  color: var(--muted);
  max-width: 52ch;
}

.analogy {
  margin-top: 1.75rem;
  padding: 0.25rem 0 0.25rem 1.5rem;
  border-left: 1px solid var(--accent);
  color: var(--text-2);
  font-size: 1.08rem;
  max-width: 52ch;
}

/* ---------- Ảnh duotone ---------- */
.photo {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--panel);
}
.photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.05) brightness(0.85);
}
.photo::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: var(--accent);
  mix-blend-mode: color;
  opacity: 0.25;
  pointer-events: none;
}
.photo::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(180deg, transparent 40%, rgba(10, 13, 12, 0.55));
  pointer-events: none;
}
.photo-cap {
  margin-top: 1rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--muted);
  padding-left: 0.75rem;
  border-left: 1px solid var(--accent);
}

/* ============================================================
   Đặc điểm — index list kiểu mục lục
   ============================================================ */
.watermark {
  position: absolute;
  right: 0;
  top: 1rem;
  z-index: 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(8rem, 22vw, 17rem);
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px rgba(148, 190, 170, 0.1);
  pointer-events: none;
  user-select: none;
}

.index-list {
  position: relative;
  z-index: 1;
  list-style: none;
  margin-top: clamp(2.5rem, 5vw, 3.5rem);
  border-top: 1px solid var(--line);
}

.index-item {
  display: grid;
  grid-template-columns: 5rem 1fr;
  gap: 1.25rem;
  padding: 1.6rem 0.25rem;
  border-bottom: 1px solid var(--line);
  transition: padding-left 0.3s var(--ease);
}
.index-item:hover {
  padding-left: 1rem;
}

.index-num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  line-height: 1;
  color: var(--muted);
  transition: color 0.25s var(--ease);
}
.index-item:hover .index-num {
  color: var(--accent);
}

.index-body h3 {
  font-size: clamp(1.2rem, 2vw, 1.45rem);
  margin-bottom: 0.35rem;
}
.index-body p {
  color: var(--muted);
  font-size: 0.95rem;
  max-width: 60ch;
}

/* ============================================================
   Timeline
   ============================================================ */
.steps {
  position: relative;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
  margin-top: clamp(2.5rem, 5vw, 3.5rem);
  counter-reset: step;
}
/* đường nối ngang (đứt đoạn) */
.steps::before {
  content: "";
  position: absolute;
  top: 23px;
  left: 2%;
  right: 2%;
  border-top: 1px dashed var(--line-strong);
}

.step {
  position: relative;
}

.step-marker {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 3.4rem;
  height: 46px;
  padding-inline: 0.25rem;
  background: var(--bg);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  margin-bottom: 0.75rem;
  position: relative;
  z-index: 1;
}
.step-marker::before {
  content: "[";
  margin-right: 0.35rem;
  color: var(--muted);
}
.step-marker::after {
  content: "]";
  margin-left: 0.35rem;
  color: var(--muted);
}

.step h3 {
  font-size: 1.15rem;
  margin-bottom: 0.4rem;
}
.step p {
  color: var(--muted);
  font-size: 0.92rem;
  max-width: 30ch;
}

.consensus {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.8rem 1.25rem;
  margin-top: clamp(2.5rem, 5vw, 3.5rem);
  padding-top: 1.75rem;
  border-top: 1px solid var(--line);
}
.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.chip {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-2);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  padding: 0.35rem 0.8rem;
}

/* ============================================================
   Ứng dụng — statement rows
   ============================================================ */
.use-list {
  border-top: 1px solid var(--line);
}

.use-row {
  display: grid;
  grid-template-columns: 3.5rem 1fr 1.2fr auto;
  gap: 1.5rem;
  align-items: baseline;
  padding: 1.75rem 0.25rem;
  border-bottom: 1px solid var(--line);
  transition:
    padding-left 0.25s var(--ease),
    background 0.25s var(--ease);
}
.use-row:hover {
  padding-left: 0.75rem;
  background: linear-gradient(90deg, var(--accent-dim), transparent 60%);
}

.use-num {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--muted);
}
.use-row h3 {
  font-size: clamp(1.3rem, 2.4vw, 1.7rem);
}
.use-row p {
  color: var(--muted);
  font-size: 0.95rem;
  max-width: 42ch;
}
.use-domain {
  justify-self: end;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-2);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  padding: 0.25rem 0.6rem;
}

/* ============================================================
   Manifesto
   ============================================================ */
.manifesto {
  padding-block: clamp(5rem, 11vw, 8.5rem);
  text-align: center;
  background:
    radial-gradient(
      ellipse 60% 80% at 50% 50%,
      rgba(61, 220, 151, 0.08),
      transparent 70%
    ),
    var(--bg);
  border-block: 1px solid var(--line);
}

.manifesto-mark {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 1.1rem;
  margin-bottom: 1.25rem;
}

.manifesto-text {
  font-size: clamp(1.9rem, 4.6vw, 3.1rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
  max-width: 22ch;
  margin-inline: auto;
}

/* ============================================================
   Tài nguyên
   ============================================================ */
.res-rows {
  border-top: 1px solid var(--line);
}

.res-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.35rem 0.25rem;
  border-bottom: 1px solid var(--line);
  transition: padding-left 0.25s var(--ease);
}
.res-row:hover {
  padding-left: 0.75rem;
}

.res-name {
  font-weight: 600;
  font-size: 1.05rem;
}
.res-url {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--muted);
}
.res-icon {
  margin-left: auto;
  color: var(--accent);
  font-size: 1.15rem;
}

/* ============================================================
   Footer
   ============================================================ */
.site-footer {
  border-top: 1px solid var(--line);
  padding-top: clamp(3rem, 6vw, 4.5rem);
  background: var(--bg-soft);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 2rem;
  padding-bottom: 2.5rem;
}

.footer-brand p {
  color: var(--muted);
  font-size: 0.92rem;
  margin-top: 1rem;
  max-width: 38ch;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}
.footer-links a {
  color: var(--text-2);
  font-size: 0.92rem;
  transition: color 0.2s var(--ease);
}
.footer-links a:hover {
  color: var(--accent);
}

.footer-note {
  color: var(--muted);
  font-size: 0.85rem;
  max-width: 26ch;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding-block: 1.25rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.85rem;
}

/* ============================================================
   Reveal (kích hoạt bởi script.js)
   ============================================================ */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition:
    opacity 0.6s var(--ease),
    transform 0.6s var(--ease);
  transition-delay: var(--d, 0s);
}
.js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 900px) {
  .hero-grid,
  .split {
    grid-template-columns: 1fr;
  }
  .hero {
    min-height: auto;
  }
  .hero-visual {
    max-width: 480px;
  }
}

@media (max-width: 820px) {
  .nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--bg-soft);
    border-bottom: 1px solid var(--line);
    padding: 0 clamp(1.25rem, 4vw, 2rem);
    max-height: 0;
    overflow: hidden;
    transition:
      max-height 0.35s var(--ease),
      padding 0.35s var(--ease);
  }
  .nav-links.open {
    max-height: 340px;
    padding-block: 0.75rem 1.25rem;
  }
  .nav-links a {
    padding: 0.85rem 0;
    border-bottom: 1px solid var(--line);
  }
  .nav-links a::after {
    display: none;
  }
}

@media (max-width: 880px) {
  .index-item {
    grid-template-columns: 4rem 1fr;
  }
}

@media (max-width: 760px) {
  .steps {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  .steps::before {
    top: 0;
    bottom: 0;
    left: 25px;
    right: auto;
    width: 1px;
    height: auto;
    border-top: 0;
    border-left: 1px dashed var(--line-strong);
  }
  .step {
    padding-left: 4rem;
  }
  .step-marker {
    position: absolute;
    left: 0;
    top: 0;
    margin: 0;
  }
}

@media (max-width: 640px) {
  .index-item {
    grid-template-columns: 3rem 1fr;
    gap: 0.75rem;
  }
  .use-row {
    grid-template-columns: 2.5rem 1fr;
    row-gap: 0.5rem;
  }
  .use-row p {
    grid-column: 2;
  }
  .use-domain {
    grid-column: 2;
    justify-self: start;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 1.75rem;
  }
  .res-row {
    flex-wrap: wrap;
    row-gap: 0.25rem;
  }
  .res-icon {
    margin-left: 0;
  }
}

/* ============================================================
   Giảm chuyển động
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .js [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
}