:root {
  --bg-0: #06080F;
  --bg-1: #0B1220;
  --bg-2: #131B2E;
  --bg-3: #1B2540;
  --line: rgba(255, 255, 255, 0.08);
  --text: #E6EDF7;
  --muted: #8FA3C2;
  --dim: #5A6D8F;
  --cyan: #4FC3F7;
  --cyan-dim: rgba(79, 195, 247, 0.18);
  --green: #6EE7B7;
  --green-dim: rgba(110, 231, 183, 0.18);
  --amber: #FBBF24;
  --amber-dim: rgba(251, 191, 36, 0.18);
  --red: #F87171;
  --red-dim: rgba(248, 113, 113, 0.18);
  --violet: #C084FC;
  --pink: #F472B6;
  --font-sans: "Inter", "Noto Sans JP", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", "Cascadia Code", ui-monospace, monospace;
  --font-jp: "Noto Sans JP", "Hiragino Kaku Gothic ProN", sans-serif;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg-0);
  color: var(--text);
  font-family: var(--font-jp), var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(900px circle at 15% -10%, rgba(79, 195, 247, 0.15), transparent 60%),
    radial-gradient(800px circle at 85% 10%, rgba(192, 132, 252, 0.10), transparent 60%),
    radial-gradient(1000px circle at 50% 110%, rgba(110, 231, 183, 0.08), transparent 60%);
  pointer-events: none;
  z-index: 0;
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
  z-index: 0;
  mask-image: radial-gradient(ellipse at center, rgba(0,0,0,1) 30%, rgba(0,0,0,0.3) 70%, rgba(0,0,0,0) 100%);
}

main, header, nav, footer {
  position: relative;
  z-index: 1;
}

/* ============ Header ============ */

header.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(16px);
  background: rgba(6, 8, 15, 0.7);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 14px 28px;
  display: flex;
  align-items: center;
  gap: 18px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text);
}

.brand-logo {
  width: 36px;
  height: 36px;
  border: 2px solid var(--cyan);
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 15px;
  color: var(--cyan);
  background: var(--cyan-dim);
  box-shadow: 0 0 18px rgba(79, 195, 247, 0.4);
  letter-spacing: -0.5px;
}

.brand-name {
  font-family: var(--font-jp);
  font-weight: 700;
  font-size: 17px;
  letter-spacing: 0.4px;
}

.brand-tagline {
  color: var(--dim);
  font-family: var(--font-mono);
  font-size: 12px;
  margin-left: 6px;
}

nav.site-nav {
  margin-left: auto;
  display: flex;
  gap: 22px;
}

nav.site-nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  font-family: var(--font-mono);
  letter-spacing: 0.5px;
  transition: color 0.2s;
}

nav.site-nav a:hover,
nav.site-nav a.active {
  color: var(--cyan);
  text-shadow: 0 0 12px rgba(79, 195, 247, 0.6);
}

/* ============ Layout ============ */

main {
  max-width: 980px;
  margin: 0 auto;
  padding: 80px 28px 120px;
}

section {
  margin: 96px 0;
}

section:first-child {
  margin-top: 24px;
}

/* ============ Hero ============ */

.hero {
  text-align: center;
  padding: 60px 0 40px;
}

.hero-chip {
  display: inline-block;
  padding: 6px 14px;
  border-radius: 999px;
  background: var(--cyan-dim);
  border: 1px solid rgba(79, 195, 247, 0.4);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 1.5px;
  margin-bottom: 28px;
}

.hero h1 {
  font-family: var(--font-jp);
  font-size: clamp(28px, 5vw, 52px);
  line-height: 1.25;
  letter-spacing: -0.5px;
  margin: 0 0 28px;
  background: linear-gradient(120deg, #E6EDF7 0%, var(--cyan) 50%, var(--green) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-sub {
  font-size: 18px;
  color: var(--muted);
  line-height: 1.85;
  max-width: 720px;
  margin: 0 auto 50px;
}

.hero-result {
  display: inline-flex;
  align-items: stretch;
  gap: 0;
  border-radius: 18px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--bg-1);
  box-shadow: 0 30px 80px -30px rgba(79, 195, 247, 0.4);
}

.hero-result-cell {
  padding: 22px 36px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  min-width: 160px;
}

.hero-result-cell.divider {
  background: var(--bg-2);
  min-width: 0;
  padding: 22px 14px;
  font-family: var(--font-mono);
  color: var(--dim);
  justify-content: center;
}

.hero-result-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--dim);
}

.hero-result-value {
  font-family: var(--font-mono);
  font-size: 44px;
  font-weight: 700;
  line-height: 1;
}

.hero-result-cell.winner .hero-result-value {
  color: var(--green);
  text-shadow: 0 0 20px rgba(110, 231, 183, 0.6);
}

.hero-result-cell.loser .hero-result-value {
  color: var(--muted);
}

.hero-cta {
  display: flex;
  gap: 14px;
  justify-content: center;
  margin-top: 50px;
  flex-wrap: wrap;
}

.btn {
  padding: 14px 26px;
  border-radius: 12px;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.6px;
  text-decoration: none;
  font-weight: 600;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.btn-primary {
  background: var(--cyan);
  color: #021019;
}

.btn-primary:hover {
  box-shadow: 0 0 28px rgba(79, 195, 247, 0.8);
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--text);
}

.btn-ghost:hover {
  border-color: var(--cyan);
  color: var(--cyan);
}

/* ============ Sections ============ */

h2.section-title {
  font-family: var(--font-jp);
  font-size: 32px;
  margin: 0 0 10px;
  letter-spacing: -0.5px;
  display: flex;
  align-items: baseline;
  gap: 14px;
}

h2.section-title::before {
  content: attr(data-index);
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--cyan);
  letter-spacing: 2px;
  font-weight: 400;
}

.section-lead {
  color: var(--muted);
  margin: 0 0 36px;
  font-size: 16px;
}

/* ============ Result Table ============ */

.result-table {
  border-collapse: separate;
  border-spacing: 0;
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 14px;
  overflow: hidden;
  font-family: var(--font-mono);
  background: var(--bg-1);
}

.result-table th,
.result-table td {
  padding: 14px 20px;
  text-align: left;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.result-table th {
  background: var(--bg-2);
  font-weight: 600;
  letter-spacing: 1px;
  color: var(--muted);
  text-transform: uppercase;
  font-size: 11px;
}

.result-table tr:last-child td {
  border-bottom: 0;
}

.result-table td.num {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.result-table tr.highlight {
  background: linear-gradient(90deg, rgba(110, 231, 183, 0.12), rgba(79, 195, 247, 0.06));
}

.result-table tr.highlight td {
  color: var(--text);
  font-weight: 700;
}

.result-table tr.bad td.num {
  color: var(--red);
}

.result-table tr.win td.num {
  color: var(--green);
}

/* ============ Cards ============ */

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 30px;
}

.card {
  background: var(--bg-1);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 26px 26px 28px;
  position: relative;
  overflow: hidden;
  transition: transform 0.2s, border-color 0.2s;
}

.card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--green));
  opacity: 0.6;
}

.card.bad::before {
  background: linear-gradient(90deg, var(--red), var(--amber));
}

.card.amber::before {
  background: linear-gradient(90deg, var(--amber), var(--cyan));
}

.card.violet::before {
  background: linear-gradient(90deg, var(--violet), var(--pink));
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(79, 195, 247, 0.4);
}

.card-tag {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--cyan);
  text-transform: uppercase;
}

.card h3 {
  font-family: var(--font-jp);
  font-size: 22px;
  margin: 10px 0 14px;
  letter-spacing: -0.3px;
}

.card p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.8;
}

.card-value {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
}

.card-value strong {
  font-family: var(--font-mono);
  font-size: 28px;
  color: var(--green);
}

.card.bad .card-value strong {
  color: var(--red);
}

.card.amber .card-value strong {
  color: var(--amber);
}

.card-value span {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--dim);
  letter-spacing: 1px;
}

/* ============ Code Block ============ */

pre {
  background: var(--bg-1);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 22px 24px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--text);
  position: relative;
}

pre::before {
  content: attr(data-lang);
  position: absolute;
  top: 8px;
  right: 14px;
  font-size: 10px;
  letter-spacing: 1.5px;
  color: var(--dim);
  text-transform: uppercase;
}

code {
  font-family: var(--font-mono);
}

p code, li code, td code {
  background: var(--bg-2);
  border: 1px solid var(--line);
  padding: 1px 8px;
  border-radius: 5px;
  font-size: 0.92em;
  color: var(--cyan);
}

/* ============ Math ============ */

.math-block {
  background: var(--bg-1);
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  border-radius: 10px;
  padding: 18px 24px;
  margin: 22px 0;
  font-family: var(--font-mono);
  color: var(--text);
  overflow-x: auto;
}

.math-block .label {
  font-size: 11px;
  color: var(--dim);
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 8px;
  font-family: var(--font-mono);
}

/* ============ Gate Visual ============ */

.gates-visual {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  max-width: 280px;
  margin: 30px auto;
}

.gate-cell {
  aspect-ratio: 1;
  background: var(--cyan-dim);
  border: 1px solid rgba(79, 195, 247, 0.5);
  border-radius: 8px;
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 14px rgba(79, 195, 247, 0.2);
  animation: gate-pulse 4s ease-in-out infinite;
}

.gate-cell:nth-child(odd) {
  animation-delay: 0.5s;
}

.gate-cell:nth-child(3n) {
  background: var(--green-dim);
  border-color: rgba(110, 231, 183, 0.4);
  color: var(--green);
}

@keyframes gate-pulse {
  0%, 100% { box-shadow: 0 0 14px rgba(79, 195, 247, 0.15); }
  50% { box-shadow: 0 0 24px rgba(79, 195, 247, 0.45); }
}

/* ============ Story Section ============ */

.story {
  background: linear-gradient(135deg, var(--bg-1), var(--bg-2));
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 32px 36px;
  margin: 30px 0;
  border-left: 4px solid var(--amber);
}

.story.bad {
  border-left-color: var(--red);
}

.story.good {
  border-left-color: var(--green);
}

.story h3 {
  font-family: var(--font-jp);
  margin: 0 0 14px;
  color: var(--amber);
  font-size: 20px;
}

.story.bad h3 {
  color: var(--red);
}

.story.good h3 {
  color: var(--green);
}

.story p {
  margin: 0 0 10px;
  color: var(--text);
  line-height: 1.9;
}

.story p:last-child {
  margin-bottom: 0;
}

/* ============ Text Body ============ */

main p, main li {
  color: var(--text);
  font-size: 15.5px;
  line-height: 1.95;
}

main p {
  margin: 18px 0;
}

main strong {
  color: var(--cyan);
  font-weight: 700;
}

main em {
  color: var(--amber);
  font-style: normal;
  font-weight: 600;
}

main a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px dashed rgba(79, 195, 247, 0.4);
  transition: all 0.15s;
}

main a:hover {
  color: var(--green);
  border-bottom-color: var(--green);
}

main h3 {
  font-family: var(--font-jp);
  font-size: 22px;
  margin: 38px 0 10px;
  color: var(--text);
  letter-spacing: -0.3px;
}

main h4 {
  font-family: var(--font-jp);
  font-size: 17px;
  margin: 28px 0 8px;
  color: var(--cyan);
}

main blockquote {
  border-left: 3px solid var(--cyan);
  margin: 24px 0;
  padding: 4px 22px;
  color: var(--muted);
  font-style: italic;
}

/* ============ Footer ============ */

footer.site-footer {
  border-top: 1px solid var(--line);
  padding: 32px 28px 48px;
  background: var(--bg-0);
  color: var(--dim);
  font-size: 13px;
  font-family: var(--font-mono);
  text-align: center;
  margin-top: 80px;
}

footer.site-footer a {
  color: var(--muted);
  margin: 0 8px;
  text-decoration: none;
}

footer.site-footer a:hover {
  color: var(--cyan);
}

/* ============ Misc ============ */

.divider-line {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 70px 0;
}

.kbd {
  font-family: var(--font-mono);
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-bottom-width: 2px;
  border-radius: 5px;
  padding: 2px 7px;
  font-size: 12px;
  color: var(--cyan);
}

.fade-in {
  animation: fadein 0.8s ease-out;
}

@keyframes fadein {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ============ Responsive ============ */

@media (max-width: 720px) {
  .header-inner { padding: 12px 20px; }
  nav.site-nav { gap: 14px; }
  nav.site-nav a { font-size: 12px; }
  main { padding: 50px 20px 80px; }
  section { margin: 64px 0; }
  .hero { padding: 30px 0 20px; }
  .hero-result { flex-direction: column; }
  .hero-result-cell.divider { display: none; }
  h2.section-title { font-size: 26px; }
}