:root {
  --navy: #0f172a;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --bg: #ffffff;
  --surface-alt: #f8fafc;
  --hover-bg: #f1f5f9;
  --text: #0f172a;
  --text-mid: #475569;
  --text-light: #94a3b8;
  --text-faint: #94a3b8;
  --border: #e2e8f0;
  --code-bg: #f1f5f9;
  --code-text: #e2e8f0;
  --font-heading: 'Sora', sans-serif;
  --font-body: 'Source Sans 3', sans-serif;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

h1,
h2,
h3,
nav,
.section-title,
.talk-name,
.post-title {
  font-family: var(--font-heading);
}

/* ---- NAV ---- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.9);
}

nav {
  max-width: 720px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative;
}

.nav-name {
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--navy);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 1.8rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-mid);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 400;
  transition: color 0.2s, border-color 0.2s;
  border-bottom: 1px solid transparent;
  padding-bottom: 0.1rem;
}

.nav-links a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ---- HAMBURGER ---- */
.hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  z-index: 101;
}

.hamburger span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--navy);
  margin: 4px 0;
  transition: all 0.3s;
}

.hamburger.open span:nth-child(1) {
  transform: rotate(45deg) translate(3px, 4px);
}

.hamburger.open span:nth-child(2) {
  opacity: 0;
}

.hamburger.open span:nth-child(3) {
  transform: rotate(-45deg) translate(3px, -4px);
}

/* ---- CONTENT ---- */
.content {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ---- HERO ---- */
.hero {
  padding: 6rem 0 6.5rem;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 240px;
  gap: 3.5rem;
  align-items: center;
}

.intro {
  grid-column: 1;
  grid-row: 1;
  text-align: left;
  max-width: 500px;
}

.intro h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--navy);
  letter-spacing: -0.02em;
  line-height: 1.05;
  margin-bottom: 0;
}

.hero-tagline {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.01em;
  line-height: 1.28;
  margin-top: 0.875rem;
  margin-bottom: 1.375rem;
  transition: color 180ms ease-out, letter-spacing 180ms ease-out;
}

.hero-tagline:hover {
  color: var(--navy);
  letter-spacing: 0;
}

.hero-copy p {
  font-family: var(--font-body);
  font-size: 1.0625rem;
  font-weight: 400;
  color: var(--text-mid);
  line-height: 1.65;
  max-width: 500px;
  margin-bottom: 0;
}

.hero-copy p + p {
  margin-top: 0.5625rem;
}

.photo-section {
  grid-column: 2;
  grid-row: 1;
  display: flex;
  justify-content: flex-end;
  align-items: center;
}

.photo-section img {
  width: 240px;
  height: 280px;
  object-fit: cover;
}

/* ---- SECTION TITLES ---- */
.section-title {
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--navy);
  margin-bottom: 1.5rem;
}

.section-title-link {
  display: inline-block;
  text-decoration: none;
  transition: color 180ms ease-out;
}

.section-title-link:hover {
  color: var(--accent);
}

.section-inner {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ---- TALKS ---- */
.talks-section {
  margin-top: 0;
  position: relative;
  left: 50%;
  right: 50%;
  width: 100vw;
  margin-left: -50vw;
  margin-right: -50vw;
  padding: 5rem 0;
  background: var(--surface-alt);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.talk {
  padding: 1.5rem 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 1.25rem;
  align-items: baseline;
}

.talk + .talk {
  border-top: 1px solid var(--border);
}

.talk-name {
  font-size: 1.1875rem;
  font-weight: 600;
  color: var(--navy);
  letter-spacing: -0.01em;
}

.talk-name a {
  color: var(--navy);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 180ms ease-out, border-color 180ms ease-out;
}

.talk-name a:visited {
  color: var(--navy);
}

.talk-name a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.talk-detail {
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-faint);
  white-space: nowrap;
  text-align: right;
}

/* ---- WRITING ---- */
.writing-section {
  position: relative;
  left: 50%;
  right: 50%;
  width: 100vw;
  margin-left: -50vw;
  margin-right: -50vw;
  padding: 5rem 0;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}

.post {
  padding: 1.5rem 0;
}

.post + .post {
  border-top: 1px solid var(--border);
}

.post-title {
  font-size: 1.1875rem;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 0.375rem;
  letter-spacing: -0.01em;
}

.post-title a {
  color: var(--navy);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 180ms ease-out, border-color 180ms ease-out;
}

.post-title a:visited {
  color: var(--navy);
}

.post-title a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.post-desc {
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--text-mid);
  line-height: 1.65;
  max-width: 600px;
}

/* ---- SINGLE PAGE ---- */
.page-content {
  max-width: 600px;
  margin-top: 4rem;
}

.page-content h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--navy);
  letter-spacing: -0.02em;
  line-height: 1.05;
  margin-bottom: 1.5rem;
}

.page-content h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--navy);
  letter-spacing: -0.01em;
  margin-top: 2.75rem;
  margin-bottom: 1rem;
}

.page-content h3 {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--navy);
  letter-spacing: -0.01em;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.page-content p {
  font-size: 1rem;
  font-family: var(--font-body);
  color: var(--text-mid);
  line-height: 1.65;
  max-width: 600px;
  margin-bottom: 1rem;
}

.page-content a {
  color: var(--navy);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 180ms ease-out, border-color 180ms ease-out;
}

.page-content a:visited {
  color: var(--navy);
}

.page-content a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.page-content ul,
.page-content ol {
  margin: 1rem 0 1.2rem 1.5rem;
  color: var(--text-mid);
}

.page-content li {
  margin-bottom: 0.625rem;
  font-size: 1rem;
  line-height: 1.65;
}

.page-content blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 1.25rem;
  margin: 1.5rem 0;
  color: var(--text-mid);
  font-style: italic;
}

.page-content code {
  font-size: 0.9em;
  background: var(--code-bg);
  padding: 0.15em 0.4em;
  border-radius: 3px;
}

.page-content pre {
  background: var(--navy);
  color: var(--code-text);
  padding: 1.2rem 1.4rem;
  overflow-x: auto;
  margin: 1.5rem 0;
  font-size: 0.84rem;
  line-height: 1.5;
}

.page-content pre code {
  background: none;
  padding: 0;
  border-radius: 0;
  color: inherit;
}

.post-meta {
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-faint);
  margin-bottom: 1.5rem;
}

.post-date {
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-faint);
  margin-bottom: 0.5rem;
}

.writing-group + .writing-group {
  margin-top: 4rem;
}

.writing-list .writing-entry {
  padding: 1.5rem 0;
}

.writing-list .writing-entry + .writing-entry {
  border-top: 1px solid var(--border);
}

.writing-entry-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
}

.writing-meta {
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-faint);
  white-space: nowrap;
  text-align: right;
}

.writing-submeta {
  font-family: var(--font-body);
  font-size: 0.9375rem;
  color: var(--text-mid);
  line-height: 1.6;
  margin-top: 0.35rem;
}

.writing-more-link {
  display: inline-block;
  margin-top: 1.5rem;
  font-family: var(--font-heading);
  font-size: 0.875rem;
  font-weight: 600;
}

.writing-placeholder {
  font-size: 1rem;
  color: var(--text-mid);
  max-width: 600px;
  margin-top: 1rem;
}

.writing-page .writing-group + .writing-group {
  margin-top: 5.5rem;
}

.writing-page .writing-group h2 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 1.75rem;
}

.writing-page .posts-group .writing-list .writing-entry {
  padding: 0;
}

.writing-page .posts-group .writing-list .writing-entry + .writing-entry {
  margin-top: 1.75rem;
  padding-top: 1.75rem;
  border-top: 1px solid rgba(226, 232, 240, 0.7);
}

.writing-page .posts-group .post-title {
  font-size: 1.125rem;
}

.writing-page .posts-group .post-desc {
  font-size: 0.96875rem;
  max-width: 600px;
}

.writing-page .publications-group {
  padding-top: 3.25rem;
  border-top: 1px solid var(--border);
}

.writing-page .publications-list .writing-entry {
  max-width: 600px;
  padding: 0;
}

.writing-page .publications-list .writing-entry + .writing-entry {
  margin-top: 2.25rem;
  padding-top: 0;
  border-top: none;
}

.writing-page .publication-entry .post-title {
  font-size: 1.125rem;
  margin-bottom: 0;
}

.publication-meta-block {
  max-width: 600px;
  margin-top: 0.75rem;
}

.publication-authors {
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--text-mid);
  line-height: 1.58;
}

.publication-authors strong {
  font-weight: 600;
  color: var(--navy);
}

.publication-reference {
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--text-mid);
  line-height: 1.55;
  margin-top: 0.4rem;
}

.writing-page .publication-entry .writing-submeta {
  font-size: 0.875rem;
  line-height: 1.55;
  margin-top: 0.4rem;
}

.writing-page .publication-entry .writing-citation {
  color: var(--text-faint);
}

.writing-page .publication-entry .post-desc {
  max-width: 600px;
  margin-top: 0.65rem;
  font-size: 0.9375rem;
  color: var(--text-mid);
}

.blog-list .post {
  padding: 1.5rem 0;
}

/* ---- FOOTER ---- */
footer {
  margin-top: 6rem;
  position: relative;
  left: 50%;
  right: 50%;
  width: 100vw;
  margin-left: -50vw;
  margin-right: -50vw;
  padding: 2.5rem 0 3rem;
  background: #0f172a;
  border-top: 1px solid #1e293b;
}

.home footer {
  margin-top: 0;
}

.footer-content {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-copy {
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: #94a3b8;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

.footer-links a {
  font-family: var(--font-heading);
  font-size: 0.875rem;
  font-weight: 500;
  color: #cbd5e1;
  text-decoration: none;
  transition: color 0.2s, border-color 0.2s;
  border-bottom: 1px solid transparent;
  padding-bottom: 0.1rem;
}

.footer-links a:hover {
  color: #60a5fa;
  border-bottom-color: #60a5fa;
}

/* ---- RESPONSIVE ---- */
@media (max-width: 640px) {
  nav {
    padding: 0.9rem 1.5rem;
  }

  .hamburger {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: calc(100% + 0.8rem);
    right: 0;
    background: rgba(255, 255, 255, 0.98);
    flex-direction: column;
    gap: 0;
    padding: 0.5rem 0;
    border: 1px solid var(--border);
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(31, 41, 55, 0.08);
    z-index: 100;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li a {
    display: block;
    padding: 0.7rem 1.5rem;
  }

  .hero {
    padding: 4.5rem 0 4.75rem;
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .talks-section,
  .writing-section {
    padding: 3.5rem 0;
  }

  .section-inner {
    padding: 0 1.5rem;
  }

  .photo-section {
    grid-column: auto;
    grid-row: auto;
    justify-content: flex-start;
  }

  .intro {
    grid-column: auto;
    grid-row: auto;
  }

  .photo-section img {
    width: 200px;
    height: 230px;
  }

  .intro h1 {
    font-size: 2.25rem;
  }

  .hero-tagline {
    font-size: 1.375rem;
    margin-top: 0.75rem;
    margin-bottom: 1rem;
  }

  .hero-copy p {
    max-width: 100%;
    font-size: 1rem;
  }

  .talk {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }

  .talk-detail {
    white-space: normal;
    text-align: left;
  }

  .page-content {
    max-width: 100%;
  }

  .writing-entry-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.35rem;
  }

  .writing-meta {
    white-space: normal;
    text-align: left;
  }

  .writing-page .writing-group + .writing-group {
    margin-top: 4.5rem;
  }

  .writing-page .publications-group {
    padding-top: 2.5rem;
  }

  .writing-page .posts-group .writing-list .writing-entry + .writing-entry,
  .writing-page .publications-list .writing-entry + .writing-entry {
    margin-top: 1.75rem;
    padding-top: 1.75rem;
  }

  .footer-content {
    flex-direction: column;
    gap: 0.8rem;
    align-items: flex-start;
  }
}