:root {
  --bg: #f4f1ea;
  --surface: rgba(255, 255, 255, 0.82);
  --surface-strong: #fffdf8;
  --ink: #142027;
  --muted: #5d6a72;
  --line: #d9d2c3;
  --accent: #0f766e;
  --accent-2: #be5b00;
  --shadow: 0 18px 50px rgba(20, 32, 39, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 10% -10%, #f7d8aa 0, transparent 36%),
    radial-gradient(circle at 90% 0%, #9cd0cd 0, transparent 42%),
    linear-gradient(180deg, #f8f4eb 0%, var(--bg) 100%);
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  line-height: 1.6;
}

.bg-orb {
  position: fixed;
  border-radius: 999px;
  filter: blur(70px);
  pointer-events: none;
  opacity: 0.42;
  z-index: -1;
  animation: float 14s ease-in-out infinite;
}

.bg-orb-a {
  width: 340px;
  height: 340px;
  left: -120px;
  top: 120px;
  background: #ffd08e;
}

.bg-orb-b {
  width: 380px;
  height: 380px;
  right: -140px;
  top: 45vh;
  background: #80c9c4;
  animation-delay: -6s;
}

.hero {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: saturate(140%) blur(10px);
  background: rgba(248, 244, 235, 0.82);
  border-bottom: 1px solid rgba(217, 210, 195, 0.65);
}

.hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 1.25rem;
}

.eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.75rem;
  color: var(--accent);
  font-weight: 700;
}

.hero h1 {
  margin: 0.25rem 0;
  line-height: 1.08;
  font-size: clamp(1.35rem, 3vw, 2.2rem);
}

.subtitle {
  margin: 0;
  color: var(--muted);
  max-width: 70ch;
  font-size: 0.95rem;
}

.progress {
  height: 4px;
  width: 100%;
  background: rgba(20, 32, 39, 0.08);
}

#progressBar {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width 100ms linear;
}

.layout {
  max-width: 1200px;
  margin: 1.3rem auto 2.4rem;
  padding: 0 1.25rem;
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  gap: 1rem;
}

.toc-wrap {
  position: sticky;
  top: 118px;
  align-self: start;
  max-height: calc(100vh - 140px);
  overflow: auto;
}

.toc-card,
.content-card {
  background: var(--surface);
  border: 1px solid rgba(217, 210, 195, 0.95);
  box-shadow: var(--shadow);
  border-radius: 18px;
}

.toc-card {
  padding: 1rem;
}

.toc-card h2 {
  margin: 0 0 0.8rem;
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
}

#toc a {
  display: block;
  color: var(--ink);
  text-decoration: none;
  border-left: 3px solid transparent;
  padding: 0.34rem 0.5rem;
  margin: 0.15rem 0;
  border-radius: 8px;
  font-size: 0.9rem;
}

#toc a:hover,
#toc a.active {
  border-left-color: var(--accent);
  background: rgba(15, 118, 110, 0.08);
}

.content-card {
  padding: clamp(1rem, 2.2vw, 2.2rem);
  overflow: hidden;
}

.loading {
  margin: 0;
  color: var(--muted);
}

.content-card h1,
.content-card h2,
.content-card h3,
.content-card h4 {
  font-family: "Source Serif 4", Georgia, serif;
  line-height: 1.2;
  scroll-margin-top: 120px;
}

.content-card h1 {
  font-size: clamp(1.55rem, 2.3vw, 2.05rem);
  margin-top: 1.2rem;
}

.content-card h2 {
  font-size: clamp(1.25rem, 2vw, 1.6rem);
  margin-top: 1.7rem;
  padding-top: 0.2rem;
  border-top: 1px solid var(--line);
}

.content-card h3 {
  font-size: clamp(1.05rem, 1.4vw, 1.2rem);
  margin-top: 1.2rem;
}

.content-card p,
.content-card li {
  max-width: 78ch;
}

.content-card strong {
  color: #062f2c;
}

.content-card blockquote {
  margin: 1rem 0;
  padding: 0.8rem 1rem;
  border-left: 4px solid var(--accent-2);
  background: rgba(190, 91, 0, 0.08);
  border-radius: 10px;
}

.content-card table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.92rem;
  background: var(--surface-strong);
  border: 1px solid var(--line);
}

.content-card th,
.content-card td {
  text-align: left;
  padding: 0.58rem 0.62rem;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}

.content-card th {
  background: #f4efe4;
  position: sticky;
  top: 0;
}

.content-card code {
  font-family: "IBM Plex Sans", monospace;
  background: #f3ece0;
  padding: 0.08rem 0.28rem;
  border-radius: 4px;
}

.content-card pre {
  background: #1a2227;
  color: #eef7f5;
  border-radius: 12px;
  overflow: auto;
  padding: 1rem;
}

.content-card hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 1.6rem 0;
}

@media (max-width: 1024px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .toc-wrap {
    position: static;
    max-height: none;
  }

  #toc {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.2rem 0.4rem;
  }
}

@media (max-width: 680px) {
  .hero-inner {
    padding: 0.9rem 0.9rem;
  }

  .layout {
    padding: 0 0.65rem;
    margin-top: 0.7rem;
  }

  .content-card {
    padding: 0.9rem;
  }

  #toc {
    grid-template-columns: 1fr;
  }
}

@keyframes float {
  0%,
  100% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-22px);
  }
}