/* ============================================================
   MICHAEL WEBER — ACADEMIC WEBSITE
   style.css
   
   HOW TO READ THIS FILE:
   CSS is organized in layers — think of it like dressing:
   1. Reset / base         (the bare skin)
   2. Typography           (the fabric)
   3. Layout               (the cut/structure)
   4. Components           (individual items: nav, cards, etc.)
   5. Page-specific tweaks (final tailoring)
   ============================================================ */


/* ── 1. CUSTOM PROPERTIES (variables) ─────────────────────────
   CSS variables let you define a color ONCE and use it everywhere.
   If you want to change the accent color, you change ONE line here.
   ────────────────────────────────────────────────────────────── */
:root {
  --color-bg:         #ffffff;
  --color-text:       #1a1a1a;
  --color-muted:      #555555;
  --color-subtle:     #888888;
  --color-accent:     #1e3a5f;       /* deep navy */
  --color-accent-lt:  #2563a8;
  --color-border:     #dde3ea;
  --color-surface:    #f6f8fb;       /* cool off-white */

  --font-sans:   'Source Sans 3', system-ui, sans-serif;
  --font-serif:  'Spectral', Georgia, serif;
  --font-mono:   'JetBrains Mono', monospace;

  --nav-height:  60px;
  --sidebar-w:   260px;
  --content-max: 760px;
  --gap:         2rem;
}


/* ── 2. RESET ──────────────────────────────────────────────────
   Browsers have their own default styles that differ slightly.
   A reset levels the playing field so we start from zero.
   ────────────────────────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;                   /* 1rem = 16px everywhere */
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-accent);
  text-decoration: none;
}
a:hover {
  color: var(--color-accent-lt);
  text-decoration: underline;
}


/* ── 3. TYPOGRAPHY ─────────────────────────────────────────────
   We use Spectral (serif) for display text and Source Sans 3
   (sans-serif) for body text — a classic academic pairing.
   ────────────────────────────────────────────────────────────── */
h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.25;
  color: var(--color-text);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.4rem; margin-bottom: 1rem; }
h3 { font-size: 1.1rem; margin-bottom: 0.5rem; }

p { margin-bottom: 1rem; }
p:last-child { margin-bottom: 0; }

ul, ol {
  padding-left: 1.4em;
  margin-bottom: 1rem;
}
li { margin-bottom: 0.3rem; }

.section-title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: 0.4rem;
  margin-bottom: 1.2rem;
  margin-top: 2rem;
}
.section-title:first-child { margin-top: 0; }
.section-title:first-child { margin-top: 0; }


/* ── 4. NAVIGATION ─────────────────────────────────────────────
   The nav bar sticks to the top of the screen (position: fixed).
   Every page uses the same nav HTML, which means the same CSS
   applies everywhere — one change, site-wide effect.
   ────────────────────────────────────────────────────────────── */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  padding: 0;
  z-index: 1000;
}

/* Inner wrapper constrains nav content to match page body width */
.site-nav > *,
.site-nav .nav-brand,
.site-nav .nav-links,
.site-nav .nav-hamburger {
  /* handled via nav-inner below */
}

.site-nav {
  justify-content: center;
}

.nav-inner {
  width: 100%;
  max-width: 1100px;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  gap: 0;
}

.nav-brand {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-text);
  white-space: nowrap;
  margin-right: auto;
  text-decoration: none;
  flex-shrink: 0;
}
.nav-brand:hover {
  color: var(--color-accent);
  text-decoration: none;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 0.25rem;
  padding: 0;
  margin: 0;
}

.nav-links a {
  display: block;
  padding: 0.35rem 0.75rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-muted);
  border-radius: 4px;
  transition: color 0.15s, background 0.15s;
  text-decoration: none;
  letter-spacing: 0.01em;
}
.nav-links a:hover {
  color: var(--color-accent);
  background: rgba(30, 58, 95, 0.06);
  text-decoration: none;
}
.nav-links a.active {
  color: var(--color-accent);
  font-weight: 600;
}


/* ── 5. PAGE WRAPPER & SIDEBAR LAYOUT ─────────────────────────
   The main layout is a two-column grid:
   [sidebar 260px] [content flexible]
   
   CSS Grid is the modern way to build two-column layouts.
   Think of it like a table, but much more flexible.
   ────────────────────────────────────────────────────────────── */
.page-wrapper {
  margin-top: var(--nav-height);
  max-width: 1100px;
  margin-left: auto;
  margin-right: auto;
  padding: 3rem 2rem;
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  gap: 3.5rem;
  align-items: start;
}

/* Pages without a sidebar use this instead */
.page-wrapper.no-sidebar {
  grid-template-columns: 1fr;
  max-width: 1100px;
}


/* ── 6. SIDEBAR ────────────────────────────────────────────────
   position: sticky means the sidebar scrolls with the page
   until it hits the top, then locks in place — so the photo
   and name are always visible as you read down the content.
   ────────────────────────────────────────────────────────────── */
.sidebar {
  position: sticky;
  top: calc(var(--nav-height) + 1.5rem);
}

.sidebar-photo {
  width: 100%;
  max-width: 210px;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  border-radius: 4px;
  margin-bottom: 1.2rem;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
}

.sidebar-name {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: 0.4rem;
}

.sidebar-title {
  font-size: 0.82rem;
  color: var(--color-muted);
  line-height: 1.5;
  margin-bottom: 1.2rem;
}

.sidebar-links {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  margin-bottom: 1.4rem;
}

.sidebar-links a {
  font-size: 0.82rem;
  color: var(--color-muted);
  display: flex;
  align-items: center;
  gap: 0.45rem;
  transition: color 0.15s;
  text-decoration: none;
}
.sidebar-links a:hover {
  color: var(--color-accent);
  text-decoration: none;
}

.sidebar-links .icon {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
  opacity: 0.6;
}

.sidebar-divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 1.2rem 0;
}


/* ── 7. MAIN CONTENT AREA ──────────────────────────────────── */
.main-content {
  min-width: 0;                      /* prevents grid blowout */
  padding-top: 0.5rem;
}


/* ── 8. BIO SECTION (homepage) ─────────────────────────────── */
.bio-text {
  font-size: 1rem;
  color: var(--color-text);
  margin-bottom: 1rem;
}

.updates-list {
  list-style: none;
  padding: 0;
}

.updates-list li {
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.93rem;
  color: var(--color-muted);
  line-height: 1.6;
}
.updates-list li:last-child { border-bottom: none; }

.update-date {
  font-size: 0.78rem;
  font-family: var(--font-mono);
  color: var(--color-subtle);
  display: block;
  margin-bottom: 0.15rem;
  letter-spacing: 0.03em;
}


/* ── 9. PAPER CARDS (research page) ────────────────────────── */
.paper-list {
  list-style: none;
  padding: 0;
}

.paper-item {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--color-border);
}
.paper-item:last-child { border-bottom: none; }

.paper-title {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.25rem;
  line-height: 1.4;
}

.paper-authors {
  font-size: 0.88rem;
  color: var(--color-muted);
  margin-bottom: 0.2rem;
}

.paper-venue {
  font-size: 0.88rem;
  color: var(--color-muted);
  font-style: italic;
  margin-bottom: 0.5rem;
}

.paper-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.paper-link {
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  border: 1px solid var(--color-border);
  border-radius: 3px;
  color: var(--color-muted);
  transition: all 0.15s;
  text-decoration: none;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}
.paper-link:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: rgba(30, 58, 95, 0.04);
  text-decoration: none;
}


/* ── 10. TEACHING & TALKS ITEMS ─────────────────────────────── */
.course-item,
.talk-item {
  padding: 1rem 0;
  border-bottom: 1px solid var(--color-border);
}
.course-item:last-child,
.talk-item:last-child { border-bottom: none; }

.course-title,
.talk-title {
  font-weight: 600;
  font-size: 0.97rem;
  margin-bottom: 0.2rem;
}

.course-meta,
.talk-meta {
  font-size: 0.85rem;
  color: var(--color-muted);
  margin-bottom: 0.4rem;
}


/* ── 11. DATA & CODE TABLE ───────────────────────────────────── */
.data-item {
  padding: 1rem 0;
  border-bottom: 1px solid var(--color-border);
}
.data-item:last-child { border-bottom: none; }

.data-name {
  font-weight: 600;
  font-size: 0.97rem;
  margin-bottom: 0.2rem;
}

.data-desc {
  font-size: 0.88rem;
  color: var(--color-muted);
  margin-bottom: 0.4rem;
}

/* ── 12. BLOG / POSTS ────────────────────────────────────────── */
.post-item {
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--color-border);
}
.post-item:last-child { border-bottom: none; }

.post-title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.2rem;
}

.post-date {
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--color-subtle);
  letter-spacing: 0.03em;
  margin-bottom: 0.3rem;
}

.post-excerpt {
  font-size: 0.9rem;
  color: var(--color-muted);
}


/* ── 13. FOOTER ──────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 1.5rem 2rem;
  margin-top: 4rem;
  font-size: 0.8rem;
  color: var(--color-subtle);
  text-align: center;
}


/* ── 14. RESPONSIVE (mobile) ─────────────────────────────────── */

/* Hamburger button — hidden on desktop */
.nav-hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.4rem;
  color: var(--color-text);
  margin-left: auto;
}
.nav-hamburger svg {
  display: block;
  width: 22px;
  height: 22px;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  fill: none;
}

@media (max-width: 700px) {
  .page-wrapper {
    grid-template-columns: 1fr;
    gap: 2rem;
    padding: 1.5rem 1.2rem;
  }

  .sidebar {
    position: static;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .sidebar-photo { max-width: 140px; }

  /* Show hamburger, hide nav links by default */
  .nav-hamburger { display: block; }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    gap: 0;
    padding: 0.5rem 0;
    z-index: 999;
  }

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

  .nav-links li { width: 100%; }

  .nav-links a {
    padding: 0.75rem 1.5rem;
    font-size: 0.95rem;
    border-radius: 0;
    border-bottom: 1px solid var(--color-border);
  }
  .nav-links li:last-child a { border-bottom: none; }
}