/* ==========================================================================
   Johnny Koo — Personal Website
   Brand color: #00A0C4
   ========================================================================== */

:root {
  --brand: #00A0C4;
  --brand-dark: #0086a3;
  --brand-soft: #e5f7fb;
  --brand-mid: #5fc5dc;
  --ink: #1a1a1a;
  --ink-soft: #4a4a4a;
  --ink-muted: #7a7a7a;
  --bg: #ffffff;
  --bg-soft: #f9fafb;
  --bg-card: #ffffff;
  --line: #e8eaee;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 12px 40px rgba(0, 30, 50, 0.08);
  --nav-bg: rgba(255, 255, 255, 0.85);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --serif: "Playfair Display", "Source Serif Pro", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", Helvetica, Arial, sans-serif;
  --max-width: 1100px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 32px;
}

/* ============== Navigation ============== */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s var(--ease), background 0.3s var(--ease);
}
.nav.scrolled { border-bottom-color: var(--line); }
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}
.nav-brand {
  font-weight: 600;
  letter-spacing: -0.01em;
  font-size: 1.05rem;
}
.nav-links { display: flex; gap: 36px; align-items: center; }
.nav-link {
  font-size: 0.95rem;
  color: var(--ink-soft);
  position: relative;
  transition: color 0.2s var(--ease);
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -6px;
  height: 1.5px;
  background: var(--ink);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s var(--ease);
}
.nav-link:hover { color: var(--ink); }
.nav-link.active { color: var(--ink); }
.nav-link.active::after { transform: scaleX(1); }

/* ============== Hero ============== */
.hero {
  padding: 80px 0 64px;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 64px;
  align-items: center;
}

/* Bubbly profile photo: organic blob mask + gentle morph (no bobbing — fixed position) */
.profile-blob {
  position: relative;
  width: 100%;
  max-width: 380px;
  aspect-ratio: 1 / 1;
  margin: 0 auto;
}
.profile-blob::before {
  content: "";
  position: absolute;
  inset: -14px;
  background: linear-gradient(135deg, var(--brand) 0%, var(--brand-mid) 100%);
  border-radius: 62% 38% 56% 44% / 50% 60% 40% 50%;
  opacity: 0.18;
  animation: morph 12s ease-in-out infinite;
  z-index: 0;
}
.profile-blob img {
  position: relative;
  z-index: 1; /* lift photo above the brand glow so colors aren't muted */
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 62% 38% 56% 44% / 50% 60% 40% 50%;
  box-shadow: var(--shadow-lg);
  animation: morph 12s ease-in-out infinite;
}
@keyframes morph {
  0%, 100% { border-radius: 62% 38% 56% 44% / 50% 60% 40% 50%; }
  33%      { border-radius: 50% 50% 38% 62% / 62% 44% 56% 38%; }
  66%      { border-radius: 44% 56% 62% 38% / 38% 56% 44% 62%; }
}

.hero-text { max-width: 520px; }
.hero-eyebrow {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--brand);
  margin-bottom: 20px;
}
.hero-title {
  font-family: var(--serif);
  font-size: clamp(2.2rem, 4.6vw, 3.4rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
}
.hero-title .hangul {
  background: linear-gradient(135deg, var(--brand), var(--brand-mid));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-lede { font-size: 1.05rem; color: var(--ink-soft); margin-bottom: 12px; }
.hero-body { font-size: 1.02rem; color: var(--ink-soft); margin-bottom: 32px; }

.btn-row { display: flex; gap: 12px; flex-wrap: wrap; }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: 999px;
  border: 1.5px solid transparent;
  cursor: pointer;
  transition: all 0.2s var(--ease);
}
.btn-primary { background: var(--brand); color: white; }
.btn-primary:hover { background: var(--brand-dark); transform: translateY(-1px); box-shadow: 0 6px 20px rgba(0, 160, 196, 0.3); }
.btn-secondary { background: var(--bg-card); color: var(--ink); border-color: var(--line); }
.btn-secondary:hover { border-color: var(--ink-soft); transform: translateY(-1px); }

/* ============== Section heading ============== */
.section { padding: 56px 0; }
.section-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 32px;
}
.section-head h2 {
  font-family: var(--serif);
  font-size: 1.85rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}
.section-head .accent {
  flex: 1;
  height: 1px;
  background: linear-gradient(to right, var(--line), transparent);
}

/* ============== Collapsible cards ============== */
.cards { display: flex; flex-direction: column; gap: 16px; }

.card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.3s var(--ease), box-shadow 0.3s var(--ease), transform 0.3s var(--ease);
}
.card:hover { border-color: #d6dae1; box-shadow: var(--shadow-md); }
.card.is-open { border-color: var(--brand); box-shadow: 0 8px 32px rgba(0, 160, 196, 0.10); }

.card-trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 26px 28px;
  background: transparent;
  border: 0;
  cursor: pointer;
  font-family: var(--sans);
  text-align: left;
}
.card-trigger:focus-visible { outline: 2px solid var(--brand); outline-offset: -2px; }

.card-label { display: flex; align-items: center; gap: 16px; }
.card-icon {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  background: var(--brand-soft);
  color: var(--brand);
  border-radius: 12px;
  flex-shrink: 0;
  transition: transform 0.4s var(--ease);
}
.card.is-open .card-icon { transform: scale(1.05) rotate(-4deg); }
.card-icon svg { width: 22px; height: 22px; }

.card-title-block { display: flex; flex-direction: column; }
.card-title { font-size: 1.15rem; font-weight: 600; color: var(--ink); letter-spacing: -0.01em; }
.card-subtitle { font-size: 0.85rem; color: var(--ink-muted); margin-top: 2px; }

.card-chevron {
  color: var(--ink-muted);
  transition: transform 0.4s var(--ease), color 0.3s var(--ease);
}
.card.is-open .card-chevron { transform: rotate(180deg); color: var(--brand); }
.card-chevron svg { width: 20px; height: 20px; }

.card-body {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.62s var(--ease);
}
.card.is-open .card-body { grid-template-rows: 1fr; }
.card-body-inner {
  overflow: hidden;
  opacity: 0;
  transform: translateY(-6px);
  transition: opacity 0.55s var(--ease) 0.06s, transform 0.55s var(--ease) 0.06s;
}
.card.is-open .card-body-inner { opacity: 1; transform: translateY(0); }
.card-body-content {
  padding: 4px 28px 28px;
  border-top: 1px solid var(--line);
  margin-top: 0;
}
.card-body-content > p { color: var(--ink-soft); padding-top: 22px; }

/* Item lists inside cards */
.item-list { display: flex; flex-direction: column; gap: 18px; padding-top: 20px; }
.item {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 20px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}
.item--with-thumb {
  grid-template-columns: 140px minmax(0, 220px) 1fr;
  align-items: start;
}
.item:last-child { border-bottom: 0; }
.item-meta { font-size: 0.85rem; color: var(--ink-muted); font-variant-numeric: tabular-nums; }

.item-thumb { min-width: 0; }
.item-thumb-link {
  display: block;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
  background: var(--bg-soft);
  transition: box-shadow 0.25s var(--ease), border-color 0.25s var(--ease), transform 0.25s var(--ease);
}
.item-thumb-link:hover {
  border-color: var(--brand);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.item-thumb-link:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 3px;
}
.item-thumb img {
  width: 100%;
  aspect-ratio: 16 / 10;
  height: auto;
  object-fit: cover;
  object-position: top center;
  display: block;
}
.item--project.item--with-thumb:has(.item-project-link):hover .item-thumb-link,
.item--project.item--with-thumb:has(.item-project-link):focus-within .item-thumb-link {
  border-color: var(--brand);
  box-shadow: 0 6px 22px rgba(0, 160, 196, 0.12);
  transform: translateY(-2px);
}
.item-content h4 {
  font-size: 1.02rem;
  font-weight: 600;
  margin-bottom: 4px;
  color: var(--ink);
}
.item-content h4 a:hover { color: var(--brand); }
.item-content .role { font-size: 0.92rem; color: var(--ink-muted); margin-bottom: 8px; }
.item-content p { font-size: 0.95rem; color: var(--ink-soft); }
.item-content .tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 10px; }
.tag {
  font-size: 0.75rem;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--brand-soft);
  color: var(--brand-dark);
  font-weight: 500;
}

/* Project items with outbound links: hover hint */
.item--project:has(.item-project-link) .item-content {
  position: relative;
  padding-right: 28px;
}
.item--project:has(.item-project-link) .item-content h4 {
  transition: transform 0.25s var(--ease);
}
.item--project:has(.item-project-link):hover .item-content h4,
.item--project:has(.item-project-link):focus-within .item-content h4 {
  transform: translateX(4px);
}
.item-external-arrow {
  position: absolute;
  top: 2px;
  right: 0;
  display: grid;
  place-items: center;
  width: 22px;
  height: 22px;
  color: var(--brand);
  pointer-events: none;
  opacity: 0;
  transform: translateX(-6px);
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease);
}
.item--project:has(.item-project-link):hover .item-external-arrow,
.item--project:has(.item-project-link):focus-within .item-external-arrow {
  opacity: 1;
  transform: translateX(0);
}
.item-external-arrow svg {
  width: 18px;
  height: 18px;
}
.item-project-link { color: inherit; }
.item-project-link:hover { color: var(--brand); }

/* ============== About page ============== */
.about-page { padding: 72px 0 96px; }
.about-grid {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 64px;
  align-items: start;
}
.about-title {
  font-family: var(--serif);
  font-size: clamp(2.4rem, 4.8vw, 3.2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 32px;
}
.about-prose p { color: var(--ink-soft); font-size: 1.05rem; margin-bottom: 18px; }
.about-prose strong { color: var(--ink); font-weight: 600; }

.about-photo {
  position: relative;
  aspect-ratio: 4 / 5;
  overflow: hidden;
  border-radius: 62% 38% 56% 44% / 50% 60% 40% 50%;
  box-shadow: var(--shadow-lg);
  animation: morph 12s ease-in-out infinite;
}
.about-photo img { width: 100%; height: 100%; object-fit: cover; }

/* ============== Writing post (Markdown-rendered) ============== */
.writing-page { padding: 56px 0 96px; }
.writing-post-head { margin-bottom: 40px; }
.writing-back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink-muted);
  margin-bottom: 24px;
  transition: color 0.2s var(--ease);
}
.writing-back:hover { color: var(--brand); }
.writing-back svg { width: 16px; height: 16px; flex-shrink: 0; }
.writing-post-title {
  font-family: var(--serif);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.12;
  margin-bottom: 12px;
}
.writing-post-meta {
  font-size: 0.9rem;
  color: var(--ink-muted);
  font-variant-numeric: tabular-nums;
}
.writing-post-meta:empty { display: none; }
.writing-prose {
  max-width: 680px;
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--ink-soft);
}
.writing-prose > * + * { margin-top: 1.1em; }
.writing-prose h2 {
  font-family: var(--serif);
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--ink);
  margin-top: 1.75em;
  margin-bottom: 0.5em;
}
.writing-prose h3 {
  font-family: var(--sans);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--ink);
  margin-top: 1.5em;
}
.writing-prose a {
  color: var(--brand-dark);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.2s var(--ease);
}
.writing-prose a:hover { color: var(--brand); }
.writing-prose ul,
.writing-prose ol { padding-left: 1.35em; }
.writing-prose li { margin-top: 0.4em; }
.writing-prose code {
  font-size: 0.9em;
  padding: 0.15em 0.4em;
  border-radius: 6px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
}
.writing-prose pre {
  padding: 16px 18px;
  border-radius: var(--radius-sm);
  background: var(--bg-soft);
  border: 1px solid var(--line);
  overflow-x: auto;
  font-size: 0.88rem;
}
.writing-prose pre code {
  padding: 0;
  border: 0;
  background: none;
}
.writing-prose blockquote {
  margin: 1.25em 0;
  padding-left: 1em;
  border-left: 3px solid var(--brand);
  color: var(--ink-soft);
  font-style: italic;
}
.writing-status {
  padding: 48px 0;
  color: var(--ink-muted);
  font-size: 1rem;
}
.writing-status.is-error { color: #c94a4a; }

.writing-page .writing-post-head {
  animation: intro-up 0.98s var(--ease) 0.22s both;
}
.writing-page .writing-prose {
  animation: intro-up 0.98s var(--ease) 0.4s both;
}

/* ============== Footer ============== */
.footer {
  border-top: 1px solid var(--line);
  padding: 40px 0;
  margin-top: 32px;
}
.footer-inner {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}
.social-links { display: flex; gap: 14px; }
.social-link {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--ink-soft);
  transition: all 0.2s var(--ease);
}
.social-link:hover {
  border-color: var(--brand);
  color: var(--brand);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 160, 196, 0.15);
}
.social-link svg { width: 18px; height: 18px; }

/* ============== Intro animation (runs once on page load) ============== */
@keyframes intro-up {
  from { opacity: 0; transform: translateY(22px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes intro-down {
  from { opacity: 0; transform: translateY(-12px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes intro-scale {
  from { opacity: 0; transform: scale(0.94); }
  to   { opacity: 1; transform: scale(1); }
}
@keyframes intro-line {
  from { transform: scaleX(0); }
  to   { transform: scaleX(1); }
}

/* Nav slides down softly */
.nav-inner {
  animation: intro-down 0.88s var(--ease) both;
}

/* Hero elements stagger up. Photo scales in slightly. */
.hero .profile-blob   { animation: intro-scale 1.35s var(--ease) 0.26s both; }
.hero .hero-eyebrow   { animation: intro-up 0.98s var(--ease) 0.62s both; }
.hero .hero-title     { animation: intro-up 1.08s var(--ease) 0.74s both; }
.hero .hero-lede      { animation: intro-up 1.08s var(--ease) 0.94s both; }
.hero .hero-body      { animation: intro-up 1.08s var(--ease) 1.1s both; }
.hero .btn-row        { animation: intro-up 1.08s var(--ease) 1.28s both; }

/* About page intro — same family, slightly tighter */
.about-page .about-title  { animation: intro-up 0.98s var(--ease) 0.32s both; }
.about-page .about-prose p { animation: intro-up 0.98s var(--ease) both; }
.about-page .about-prose p:nth-of-type(1) { animation-delay: 0.5s; }
.about-page .about-prose p:nth-of-type(2) { animation-delay: 0.62s; }
.about-page .about-prose p:nth-of-type(3) { animation-delay: 0.74s; }
.about-page .about-prose p:nth-of-type(4) { animation-delay: 0.86s; }
.about-page .about-prose .btn-row { animation: intro-up 0.98s var(--ease) 1.04s both; }
.about-page .about-photo  { animation: intro-scale 1.35s var(--ease) 0.44s both, morph 14s ease-in-out 1.85s infinite; }

/* ============== Reveal-on-scroll ============== */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.86s var(--ease), transform 0.86s var(--ease);
}
.reveal.is-visible { opacity: 1; transform: translateY(0); }

/* ============== Responsive ============== */
@media (max-width: 820px) {
  .hero { padding: 56px 0 40px; }
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .profile-blob { max-width: 260px; }
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .about-photo { order: -1; }
  .about-prose { order: 1; }
  .about-photo { max-width: 320px; margin: 0 auto; }
  .item { grid-template-columns: 1fr; gap: 6px; }
  .item--with-thumb { gap: 14px; }
  .item--with-thumb .item-meta { order: 1; }
  .item--with-thumb .item-thumb { order: 2; }
  .item--with-thumb .item-content { order: 3; }
  .item-meta { order: 2; font-size: 0.8rem; }
  .nav-links { gap: 18px; }
  .nav-link { font-size: 0.88rem; }
  .container { padding: 0 22px; }
  .card-trigger { padding: 22px 20px; }
  .card-body-content { padding: 4px 20px 22px; }
  .footer-inner { justify-content: center; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}