:root {
  --ink: #0e1116;
  --ink-soft: #2a3140;
  --muted: #5c6578;
  --paper: #e7ecf2;
  --paper-deep: #d8e0ea;
  --line: rgba(14, 17, 22, 0.12);
  --accent: #0f766e;
  --accent-deep: #0b5a54;
  --accent-soft: rgba(15, 118, 110, 0.12);
  --sky: #7eb6c9;
  --glow: #c9dde8;
  --white: #f7fafc;
  --shadow: 0 24px 60px rgba(14, 17, 22, 0.12);
  --radius: 18px;
  --shell: min(1120px, calc(100% - 2.5rem));
  --narrow: min(740px, calc(100% - 2.5rem));
  --font-display: "Fraunces", Georgia, serif;
  --font-ui: "Sora", "Segoe UI", sans-serif;
  --font-body: "Source Serif 4", Georgia, serif;
  --header-h: 4.25rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(126, 182, 201, 0.28), transparent 60%),
    radial-gradient(900px 500px at 100% 8%, rgba(15, 118, 110, 0.12), transparent 55%),
    linear-gradient(180deg, #eef3f7 0%, var(--paper) 28%, #edf1f6 100%);
  font-family: var(--font-body);
  font-size: 1.125rem;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
}

img {
  max-width: 100%;
  display: block;
}

a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

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

.shell {
  width: var(--shell);
  margin-inline: auto;
}

.narrow {
  width: var(--narrow);
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -4rem;
  z-index: 100;
  padding: 0.75rem 1rem;
  background: var(--ink);
  color: var(--white);
  border-radius: 999px;
}

.skip-link:focus {
  top: 1rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  backdrop-filter: blur(14px);
  background: rgba(231, 236, 242, 0.78);
  border-bottom: 1px solid transparent;
  transition: border-color 200ms ease, background 200ms ease, box-shadow 200ms ease;
}

.site-header.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(247, 250, 252, 0.88);
  box-shadow: 0 10px 30px rgba(14, 17, 22, 0.05);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.brand-mark {
  display: inline-flex;
  align-items: baseline;
  gap: 0.1rem;
  text-decoration: none;
  font-family: var(--font-ui);
  font-weight: 700;
  letter-spacing: -0.03em;
}

.brand-mark__word {
  font-size: 1.05rem;
}

.brand-mark__tld {
  color: var(--accent);
  font-size: 0.92rem;
}

.site-nav {
  display: none;
  gap: 1.25rem;
  font-family: var(--font-ui);
  font-size: 0.86rem;
  font-weight: 500;
}

.site-nav a {
  text-decoration: none;
  color: var(--ink-soft);
}

.site-nav a:hover {
  color: var(--accent-deep);
}

.header-cta {
  display: none;
  font-family: var(--font-ui);
  font-size: 0.84rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--accent-deep);
}

.hero {
  position: relative;
  min-height: calc(100svh - var(--header-h));
  display: grid;
  align-items: end;
  overflow: hidden;
  color: var(--white);
  isolation: isolate;
}

.hero__media {
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(145deg, #102033 0%, #163247 42%, #0f766e 120%),
    radial-gradient(circle at 70% 30%, rgba(201, 221, 232, 0.35), transparent 45%);
}

.hero__wash {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(16, 32, 51, 0.15) 0%, rgba(14, 17, 22, 0.55) 58%, rgba(14, 17, 22, 0.88) 100%),
    radial-gradient(800px 400px at 20% 20%, rgba(126, 182, 201, 0.35), transparent 60%);
}

.hero__grain {
  position: absolute;
  inset: 0;
  opacity: 0.28;
  background-image:
    repeating-linear-gradient(
      0deg,
      transparent,
      transparent 2px,
      rgba(255, 255, 255, 0.015) 2px,
      rgba(255, 255, 255, 0.015) 4px
    ),
    repeating-linear-gradient(
      90deg,
      transparent,
      transparent 3px,
      rgba(0, 0, 0, 0.04) 3px,
      rgba(0, 0, 0, 0.04) 6px
    );
  mix-blend-mode: soft-light;
}

.hero__orbit {
  position: absolute;
  width: min(70vw, 680px);
  aspect-ratio: 1;
  right: -8%;
  top: 8%;
  border-radius: 50%;
  border: 1px solid rgba(247, 250, 252, 0.18);
  box-shadow:
    inset 0 0 80px rgba(126, 182, 201, 0.18),
    0 0 80px rgba(15, 118, 110, 0.2);
  animation: orbit-pulse 8s ease-in-out infinite;
}

.hero__orbit::before,
.hero__orbit::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  border: 1px solid rgba(247, 250, 252, 0.12);
}

.hero__orbit::before {
  inset: 12%;
}

.hero__orbit::after {
  inset: 28%;
  background: radial-gradient(circle, rgba(201, 221, 232, 0.22), transparent 70%);
}

.hero__content {
  position: relative;
  padding: clamp(4rem, 12vh, 7rem) 0 clamp(3.5rem, 8vh, 5.5rem);
  max-width: 56rem;
}

.hero__kicker {
  margin: 0 0 1rem;
  font-family: var(--font-ui);
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(247, 250, 252, 0.72);
}

.hero__brand {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(4.2rem, 14vw, 8.5rem);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.045em;
}

.hero__headline {
  margin: 1.25rem 0 0;
  max-width: 18ch;
  font-family: var(--font-ui);
  font-size: clamp(1.45rem, 3.4vw, 2.15rem);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.03em;
}

.hero__lede {
  margin: 1.1rem 0 0;
  max-width: 38ch;
  font-size: 1.08rem;
  color: rgba(247, 250, 252, 0.84);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-top: 2rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 3rem;
  padding: 0.85rem 1.25rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--font-ui);
  font-size: 0.92rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: transform 180ms ease, background 180ms ease, color 180ms ease, border-color 180ms ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn--primary {
  background: var(--white);
  color: var(--ink);
}

.btn--primary:hover {
  background: #ffffff;
  color: var(--ink);
}

.btn--ghost {
  border-color: rgba(247, 250, 252, 0.35);
  color: var(--white);
  background: rgba(247, 250, 252, 0.04);
}

.btn--ghost:hover {
  border-color: rgba(247, 250, 252, 0.7);
  color: var(--white);
}

.section {
  padding: clamp(4.5rem, 10vw, 7rem) 0;
}

.section-label {
  margin: 0 0 0.85rem;
  font-family: var(--font-ui);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
}

.section-title {
  margin: 0;
  font-family: var(--font-ui);
  font-size: clamp(1.85rem, 4vw, 2.75rem);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.035em;
}

.section-dek {
  margin: 1rem 0 0;
  max-width: 46rem;
  color: var(--muted);
  font-size: 1.05rem;
}

.prose p {
  margin: 0 0 1.15rem;
  color: var(--ink-soft);
}

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

.prose strong {
  color: var(--ink);
  font-weight: 600;
}

.section--intro .section-title,
.section--reading .section-title,
.section--subscribe .section-title {
  margin-bottom: 1.5rem;
}

.split {
  display: grid;
  gap: 1.75rem;
  margin-bottom: 2.75rem;
}

.principle-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.principle-list li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1rem;
  padding: 1.25rem 0;
  border-top: 1px solid var(--line);
}

.principle-list li:last-child {
  border-bottom: 1px solid var(--line);
}

.principle-list__index {
  font-family: var(--font-ui);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  padding-top: 0.2rem;
}

.principle-list h3 {
  margin: 0 0 0.4rem;
  font-family: var(--font-ui);
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}

.principle-list p {
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
}

.topics-head {
  margin-bottom: 2.5rem;
}

.topic-grid {
  display: grid;
  gap: 1.25rem;
}

.topic {
  padding: 1.5rem 0;
  border-top: 1px solid var(--line);
}

.topic:last-child {
  border-bottom: 1px solid var(--line);
}

.topic h3 {
  margin: 0 0 0.55rem;
  font-family: var(--font-ui);
  font-size: 1.2rem;
  letter-spacing: -0.02em;
}

.topic p {
  margin: 0;
  color: var(--muted);
  font-size: 1.02rem;
}

.fact-list {
  display: grid;
  gap: 0.85rem;
  margin: 2.5rem 0 0;
  padding: 1.5rem 0 0;
  border-top: 1px solid var(--line);
}

.fact-list > div {
  display: grid;
  grid-template-columns: 8rem 1fr;
  gap: 1rem;
  font-family: var(--font-ui);
  font-size: 0.95rem;
}

.fact-list dt {
  margin: 0;
  color: var(--muted);
  font-weight: 500;
}

.fact-list dd {
  margin: 0;
  font-weight: 600;
  color: var(--ink);
}

.start-panel {
  padding: clamp(1.75rem, 4vw, 2.75rem);
  border-radius: calc(var(--radius) + 6px);
  background:
    linear-gradient(160deg, rgba(255, 255, 255, 0.72), rgba(247, 250, 252, 0.5)),
    linear-gradient(135deg, rgba(15, 118, 110, 0.08), rgba(126, 182, 201, 0.16));
  border: 1px solid rgba(14, 17, 22, 0.08);
  box-shadow: var(--shadow);
}

.start-panel .section-title {
  max-width: 18ch;
  margin-bottom: 1.75rem;
}

.start-panel__grid {
  display: grid;
  gap: 1.75rem;
}

.start-aside {
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
}

.start-aside h3 {
  margin: 0 0 0.85rem;
  font-family: var(--font-ui);
  font-size: 1rem;
  letter-spacing: -0.02em;
}

.start-aside ol {
  margin: 0;
  padding-left: 1.15rem;
  color: var(--ink-soft);
  font-size: 1rem;
}

.start-aside li + li {
  margin-top: 0.55rem;
}

.subscribe-form {
  display: grid;
  gap: 0.85rem;
  margin-top: 1.75rem;
}

.subscribe-form input {
  width: 100%;
  min-height: 3.1rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(247, 250, 252, 0.85);
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 0.98rem;
  outline: none;
}

.subscribe-form input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
}

.subscribe-form .btn {
  width: 100%;
}

.form-note {
  margin: 0.15rem 0 0;
  font-family: var(--font-ui);
  font-size: 0.82rem;
  color: var(--muted);
}

.site-footer {
  padding: 2.75rem 0 3.25rem;
  border-top: 1px solid var(--line);
  background: rgba(247, 250, 252, 0.55);
}

.footer-inner {
  display: grid;
  gap: 1.5rem;
}

.footer-brand {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: 1.65rem;
  letter-spacing: -0.03em;
}

.footer-copy,
.footer-meta p {
  margin: 0;
  color: var(--muted);
  font-family: var(--font-ui);
  font-size: 0.88rem;
}

.footer-meta {
  display: grid;
  gap: 0.35rem;
}

[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 700ms ease, transform 700ms ease;
}

[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

@keyframes orbit-pulse {
  0%,
  100% {
    transform: scale(1) translateY(0);
    opacity: 0.9;
  }
  50% {
    transform: scale(1.04) translateY(-10px);
    opacity: 1;
  }
}

@media (min-width: 720px) {
  .site-nav {
    display: flex;
  }

  .header-cta {
    display: inline-flex;
  }

  .split {
    grid-template-columns: 1fr 1.05fr;
    gap: 3rem;
    align-items: start;
  }

  .topic-grid {
    grid-template-columns: 1fr 1fr;
    column-gap: 2.5rem;
  }

  .topic:nth-last-child(-n + 2) {
    border-bottom: 1px solid var(--line);
  }

  .fact-list {
    grid-template-columns: 1fr 1fr;
  }

  .start-panel__grid {
    grid-template-columns: 1.35fr 0.9fr;
    gap: 2.5rem;
    align-items: start;
  }

  .start-aside {
    padding-top: 0;
    padding-left: 1.75rem;
    border-top: 0;
    border-left: 1px solid var(--line);
  }

  .subscribe-form {
    grid-template-columns: 1fr auto;
    align-items: start;
  }

  .subscribe-form .btn {
    width: auto;
    min-width: 9.5rem;
  }

  .subscribe-form .form-note {
    grid-column: 1 / -1;
  }

  .footer-inner {
    grid-template-columns: 1fr auto;
    align-items: end;
  }

  .footer-meta {
    text-align: right;
  }
}

@media (min-width: 980px) {
  .principle-list {
    grid-template-columns: repeat(3, 1fr);
    gap: 0;
  }

  .principle-list li {
    grid-template-columns: 1fr;
    gap: 0.85rem;
    padding: 1.5rem 1.25rem 1.5rem 0;
    border-top: 0;
    border-bottom: 1px solid var(--line);
    border-right: 1px solid var(--line);
  }

  .principle-list li:first-child {
    padding-left: 0;
  }

  .principle-list li:last-child {
    border-right: 0;
    padding-right: 0;
  }

  .topic-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .hero__orbit,
  [data-reveal] {
    animation: none !important;
    transition: none !important;
    opacity: 1 !important;
    transform: none !important;
  }
}