/* ======================================================
   Reset & Base
   ====================================================== */

html, body {
  box-sizing: border-box;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  color-scheme: light dark;
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, sans-serif;
  line-height: 1.6;
  transition: background-color 260ms ease, color 260ms ease;
}

/* add a header-height variable and use it to prevent content overlap */
:root {
  --header-height: 65px;
  --bg: #ffffff;
  --surface: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --link: #054a91;
  --link-hover: #007acc;
  --link-background: rgba(5,74,145,0.06);
  --border: #e5e7eb;
  --divider: #d9dce0;
  --footer-bg: #c1c8d6;
  --controls-bg: rgba(0,0,0,0.03);
  --header-bg: #c1c8d6;
  --sidebar-bg: #f9f9f9;
}

/* system dark mode */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0f14;
    --surface: #071018;
    --text: #e6eef6;
    --muted: #9aa6b2;
    --link: #8ab4ff;
    --link-hover: #b8d7ff;
    --border: #1f2730;
    --divider: rgba(255,255,255,0.08);
    --footer-bg: #0b1220;
    --controls-bg: rgba(255,255,255,0.03);
    --header-bg: #0b1220;
    --sidebar-bg: #0b1220;
  }
}

/* explicit user theme (overrides system; JS sets html[data-theme]) */
html[data-theme="light"] {
  --bg: #ffffff;
  --surface: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --link: #054a91;
  --link-hover: #007acc;
  --border: #e5e7eb;
  --divider: #d9dce0;
  --footer-bg: #c1c8d6;
  --controls-bg: rgba(0,0,0,0.04);
  --header-bg: #c1c8d6;
  --sidebar-bg: #f9f9f9;
}

html[data-theme="dark"] {
  --bg: #1B1F23;
  --surface: #0b161d;
  --text: #e6eef6;
  --muted: #9aa6b2;
  --link: #8ab4ff;
  --link-hover: #b8d7ff;
  --link-background: #0b161d;
  --border: #1f2730;
  --divider: rgba(255,255,255,0.08);
  --footer-bg: #0b161d;
  --controls-bg: rgba(255,255,255,0.03);
  --header-bg: #0b161d;
  --sidebar-bg: #0b161d;
}

/* apply base colors */
html, body {
  background-color: var(--bg);
  color: var(--text);
  padding: 0;
}

body {
  font-family: Arial, sans-serif;
  line-height: 1.6;
  padding-top: calc(var(--header-height) + 0px);
}

/* ======================================================
   Header & Navigation
   ====================================================== */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  width: auto;
  height: var(--header-height);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--header-bg);
  padding: 0 20px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
  z-index: 1000;
}

/* center title/tagline in header */
.header-center {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.header-center h1 { margin: 0; font-size: 1.9rem; }
.header-center p { margin: 0; font-size: 0.9rem; color: var(--muted); }

/* right area: hamburger, nav links, theme toggle */
.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
  justify-content: flex-end;
  z-index: 1100;
}

/* desktop nav links (inline) */
.nav-links {
  display: flex;
  gap: 1rem;
  align-items: center;
}
nav a {
  margin: 0 10px;
  text-decoration: none;
  color: var(--link);
}
nav a:hover { color: var(--link-hover); }

/* hamburger (mobile) */
.menu-toggle {
  display: none;
  background: transparent;
  border: none;
  color: var(--text);
  font-size: 1.6rem;
  line-height: 1;
  cursor: pointer;
  margin-top: -5px;
}
.menu-toggle:hover, .menu-toggle:focus { color: var(--link-hover); outline: none; }

/* make hamburger glyph match text color */
.menu-toggle,
.header-right .menu-toggle { color: var(--text); }

/* theme toggle button */
#theme-toggle {
  position: relative;
  z-index: 1110;
  background: transparent;
  border: 1px solid rgba(0,0,0,0.08);
  padding: 6px 8px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.95rem;
  line-height: 1;
  color: var(--text);
}
#theme-toggle:hover, #theme-toggle:focus { background: var(--controls-bg); outline: none; }
html[data-theme="dark"] #theme-toggle { border-color: rgba(255,255,255,0.06); }

/* mobile nav dropdown */
@media (max-width: 850px) {
  .menu-toggle { display: block; }

  .nav-links {
    display: none;
    flex-direction: column;
    background: var(--surface);
    color: var(--text);
    position: absolute;
    right: 3.5rem;
    top: 60px;
    box-shadow: 0 6px 18px rgba(0,0,0,0.35);
    padding: 20px;
    z-index: 100;
    min-width: 100px;
    border-radius: 20px;
  }

  .nav-links a { color: var(--link); padding: 0px 0px; }
  .nav-links.open { display: flex; }
}

/* ======================================================
   Layout: content, columns, sidebar
   ====================================================== */

.content {
  max-width: 800px;
  margin: auto;
  padding: 5px 20px 5px 20px;
}

.home-columns {
  display: flex;
  gap: 40px;
  align-items: flex-start;
}

@media (max-width: 800px) {
  .home-columns { flex-direction: column; }

  /* center the sidebar box on narrow screens (text remains left-aligned) */
  .sidebar {
    max-width: 100%;
    margin-left: auto;
    margin-right: auto;
    text-align: left;
    float: none;
  }
}

/* sidebar */
.sidebar {
  /* keep responsive shrink on small screens but give a comfortable fixed width on wide screens */
  flex: 0 0 300px;
  max-width: 200px;
  background: var(--sidebar-bg);
  padding: 15px;
  border-radius: 8px;
  color: var(--text);
  margin-top: 20px;
}

/* sidebar image */
.profile-pic-sidebar {
  display: block;
  margin: 0 auto 8px auto;
  max-width: 180px;
  width: 100%;
  height: auto;
  border-radius: 8px;
}

/* sidebar spacing and icons */
.sidebar h3 { margin-top: 10px; margin-bottom: 6px; }

.sidebar-icon {
  width: 16px;
  height: 16px;
  vertical-align: top;
  margin-right: 4px;
  margin-top: 3px;
}

/* sidebar links (email/socials) */
.sidebar a {
  display: inline-flex;
  align-items: flex-start;
  gap: 8px;
  color: var(--text);
  text-decoration: none;
  font-size: 0.98rem;
  transition: color 0.2s;
}
.sidebar a:hover { color: var(--link-hover); }
.sidebar a .sidebar-icon {
  width: 16px;
  height: 16px;
  margin-right: 2px;
  margin-top: 4px;
  transition: transform 0.2s;
}
.sidebar a:hover .sidebar-icon { transform: scale(1.2); }

/* location block */
.sidebar-location {
  display: flex;
  align-items: flex-start;
  gap: 6px;
  margin: 0 0 12px 0;
}
.sidebar-location-icon { flex-shrink: 0; }
.sidebar-location-text { display: inline-block; color: var(--text); font-size: 0.98rem; line-height: 1.4; }

/* uniform sidebar spacing */
.sidebar .sidebar-location,
.sidebar p { margin-bottom: 6px; }

/* invert sidebar icons in dark mode */
[data-theme="dark"] .sidebar-location img {
  filter: invert(1);
}
[data-theme="dark"] .sidebar p img {
  filter: invert(1);
}

/* ======================================================
   Footer
   ====================================================== */

footer {
  background: var(--footer-bg);
  box-shadow: 0 -2px 5px rgba(0,0,0,0.05);
  text-align: center;
  color: var(--muted);
  margin-top: 40px;
  padding: 0;
  width: 100%;
}

.site-footer {
  padding: 18px 30px;
  max-width: 400px;
  margin: 0 auto;
  text-align: left;
}

.footer-copyright { text-align: left; color: var(--text); font-size: 0.85rem; margin-bottom: 6px; }
.footer-email { text-align: left; margin-bottom: 10px; }

/* ensure footer email matches social link color and socials behave the same */
.footer-email a,
.footer-item a,
.footer-email a:visited { color: var(--link); }
.footer_email a:hover,
.footer-item a:hover { color: var(--link-hover); }

.footer-item img,
.footer-email img { width: 18px; height: 18px; transition: transform 0.2s; }
.footer-item a:hover img,
.footer-email a:hover img { transform: scale(1.2); }

/* invert footer icons in dark mode */
[data-theme="dark"] .footer-item img {
  filter: invert(1);
}
[data-theme="dark"] .footer-email img {
  filter: invert(1);
}

.footer-social-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px 30px;
  justify-items: start;
  align-items: center;
  max-width: 400px;
  margin: 0;
}
@media (max-width: 500px) {
  .footer-social-grid { grid-template-columns: 1fr; gap: 8px 0; }
}

/* ======================================================
   Content typography & lists
   ====================================================== */

p { margin-top: 0; margin-bottom: 1em; }

.content main ul,
.content main ol {
  list-style-position: outside;
  padding-inline-start: 2rem;
  padding-left: 2rem;
  margin: 0 0 1rem 0;
}
.content main li { margin-bottom: 0.1rem; }

/* ======================================================
   Talks page styles
   ====================================================== */

.talk-year {
  border-top: 1px solid var(--divider);
  padding-top: 18px;
  margin-top: 28px;
}
.talk-year h3 { font-size: 1.3rem; font-weight: 600; margin: 0 0 12px 0; color: var(--text); letter-spacing: 0.2px; }

.talk { padding: 10px 0; }
.talk-title { margin: 0 0 6px 0; font-weight: 700; font-size: 1rem; color: var(--text); }
.talk-meta { margin: 0 0 8px 0; color: var(--muted); font-style: italic; font-size: 0.95rem; }
.talk-links { margin-bottom: 8px; }

.talk-link {
  display: inline-block;
  padding: 5px 9px;
  margin-right: 8px;
  margin-bottom: 6px;
  font-size: 0.9rem;
  color: var(--link);
  background: var(--link-background);
  border: 1px solid rgba(5,74,145,0.12);
  border-radius: 6px;
  text-decoration: none;
  transition: transform 0.12s ease, background 0.12s ease;
}
.talk-link:hover, .talk-link:focus { transform: translateY(-2px); background: rgba(5,74,145,0.12); outline: none; }

@media (max-width: 700px) {
  .talk-links { display: flex; flex-wrap: wrap; gap: 6px; }
  .talk-link { flex: 0 0 auto; }
  .talk-title { font-size: 1rem; }
  .talk-meta { font-size: 0.92rem; }
}

/* ======================================================
   Transitions & Accessibility
   ====================================================== */

/* smooth transitions */
header, footer, .site-header, .site-footer, .sidebar, .nav-links, .home-columns, .content {
  transition: background-color 260ms ease, color 260ms ease, border-color 260ms ease, box-shadow 260ms ease;
}
a, .talk-link, .footer-item a, .header-right a, #theme-toggle, .menu-toggle {
  transition: color 200ms ease, background-color 200ms ease, border-color 200ms ease, transform 120ms ease;
}
img { transition: filter 260ms ease, opacity 260ms ease; }

/* respect reduced motion */
@media (prefers-reduced-motion: reduce) {
  header, footer, .site-header, .site-footer, .sidebar, .nav-links, .home-columns, .content,
  a, .talk-link, .footer-item a, .header-right a, #theme-toggle, .menu-toggle, img {
    transition: none !important;
    animation: none !important;
  }
}