:root{
  --paper: #F5F4EE;
  --paper-dim: #ECEAE1;
  --ink: #1B1815;
  --ink-soft: #3A352E;
  --slate: #6E6759;
  --yellow: #F4C21A;
  --orange: #C9550E;
  --rule: rgba(27,24,21,0.14);
  --serif: 'Source Serif 4', Georgia, serif;
  --mono: 'IBM Plex Mono', ui-monospace, Menlo, monospace;
}

*{ box-sizing: border-box; }

html{ scroll-behavior: smooth; }

body{
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  -webkit-font-smoothing: antialiased;
  line-height: 1.5;
}

a{ color: inherit; text-decoration: none; }

a:focus-visible,
button:focus-visible{
  outline: 2px solid var(--orange);
  outline-offset: 3px;
}

.wrap{
  max-width: 760px;
  margin: 0 auto;
  padding: 0 28px;
}

/* ---------- Header ---------- */
header{
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(245,244,238,0.86);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--rule);
}
.nav-inner{
  max-width: 760px;
  margin: 0 auto;
  padding: 18px 28px;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--ink-soft);
}
.nav-inner .mark{ font-weight: 500; color: var(--ink); }
.nav-links{ display: flex; gap: 22px; }
.nav-links a{ transition: color .15s ease; }
.nav-links a:hover{ color: var(--orange); }
.nav-links a.active{ color: var(--orange); }

/* ---------- Hero ---------- */
.hero{
  min-height: 92vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 60px 28px 80px;
}
.hero-inner{
  max-width: 760px;
  margin: 0 auto;
  width: 100%;
}

.formula{
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  line-height: 0.9;
  opacity: 0;
  transform: translateY(10px);
}
.formula .pre,
.formula .suf{
  font-style: italic;
  font-weight: 400;
  color: var(--slate);
  font-size: clamp(1.3rem, 3vw, 2rem);
}
.formula .pre{ margin-right: 2px; align-self: flex-start; margin-top: 0.3em; }
.formula .suf{ margin-left: 4px; align-self: flex-end; }
.formula .root{
  font-weight: 700;
  font-size: clamp(4rem, 15vw, 9.5rem);
  letter-spacing: -0.01em;
  border-bottom: 6px solid var(--yellow);
  padding-bottom: 4px;
}

.formula.is-visible{
  animation: rise 0.9s cubic-bezier(.2,.7,.3,1) forwards;
}
@media (prefers-reduced-motion: reduce){
  .formula{ opacity: 1; transform: none; animation: none; }
}
@keyframes rise{
  to{ opacity: 1; transform: translateY(0); }
}

.cf-line{
  margin-top: 22px;
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--slate);
  letter-spacing: 0.01em;
}

.tagline{
  margin-top: 40px;
  font-size: 1.15rem;
  color: var(--ink-soft);
  max-width: 46ch;
}
.tagline em{
  font-style: italic;
  color: var(--ink);
}

/* ---------- Sections ---------- */
section{
  padding: 80px 0;
  border-top: 1px solid var(--rule);
}
h2{
  font-size: 1rem;
  font-weight: 600;
  font-style: italic;
  color: var(--slate);
  margin: 0 0 32px;
}

.about p{
  max-width: 62ch;
  font-size: 1.08rem;
  color: var(--ink-soft);
  margin: 0 0 20px;
}
.about p:last-child{ margin-bottom: 0; }

/* ---------- Work log ---------- */
.log-entry{
  display: grid;
  grid-template-columns: 46px 1fr auto;
  gap: 18px;
  padding: 22px 0;
  border-top: 1px solid var(--rule);
  align-items: baseline;
}
.log-entry:first-of-type{ border-top: none; }
.log-num{
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--slate);
}
.log-body h3{
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0 0 6px;
}
.log-body p{
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.98rem;
  max-width: 56ch;
}
.log-date{
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--slate);
  white-space: nowrap;
}

@media (max-width: 560px){
  .log-entry{ grid-template-columns: 32px 1fr; }
  .log-date{ grid-column: 2; margin-top: 6px; }
}

/* ---------- Contact ---------- */
.contact-row{
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
  font-family: var(--mono);
  font-size: 0.95rem;
}
.contact-row a{
  border-bottom: 1px solid var(--rule);
  padding-bottom: 2px;
  transition: border-color .15s ease, color .15s ease;
}
.contact-row a:hover{
  border-color: var(--orange);
  color: var(--orange);
}

footer{
  padding: 40px 0 60px;
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--slate);
}