/* ============================================================
   style.css — Simon Ress Personal Website
   Visual design follows https://www.simon-ress.de/ (Wowchemy look).
   The full specification lives in docs/style-guide.md — keep the
   two in sync. Section numbers below refer to that guide.
   Stack: pure HTML/CSS/JS (no build tools)
   ============================================================ */

/* ===== FONTS ===== */
@import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@400;700&family=Roboto+Mono&family=Roboto:wght@400;700&display=swap');

/* ===== 2. DESIGN TOKENS ===== */
:root {
  /* colour */
  --primary:         #1565c0;
  --primary-hover:   #104d92;
  --nav-accent:      #2962ff;
  --text:            rgba(0, 0, 0, .8);
  --heading:         #313131;
  --muted:           rgba(0, 0, 0, .54);
  --nav-text:        rgba(52, 73, 94, .85);
  --nav-text-hover:  #34495e;
  --nav-brand:       #2b2b2b;
  --bg:              #ffffff;
  --bg-alt:          #f7f7f7;
  --surface:         #ffffff;
  --surface-simple:  #ffffff;
  --navbar-bg:       #ffffff;
  --border:          #dee2e6;
  --card-border:     rgba(0, 0, 0, .125);
  --simple-border:   rgba(0, 0, 0, .09);
  --dropdown-border: rgba(0, 0, 0, .15);
  --dropdown-hover:  #e9ecef;
  --input-bg:        #ffffff;
  --input-text:      #495057;
  --input-border:    #ced4da;
  --code-text:       #c7254e;
  --code-bg:         #f8f8f8;
  --card-text:       #000000;
  --strong-muted:    #555555;
  --featurette-name: #333333;

  /* depth */
  --shadow-navbar:     0 .125rem .25rem rgba(0, 0, 0, .11);
  --shadow-card:       0 2px 4px rgba(0, 0, 0, .2);
  --shadow-card-hover: 0 8px 16px rgba(0, 0, 0, .2);
  --shadow-simple:     0 1px 4px rgba(0, 0, 0, .04);
  --focus-ring:        0 0 0 .2rem rgba(21, 101, 192, .25);

  /* shape */
  --radius:        .25rem;
  --radius-btn:    .3rem;
  --radius-simple: 3px;

  /* type */
  --font-body:    'Roboto', sans-serif;
  --font-heading: 'Montserrat', sans-serif;
  --font-mono:    'Roboto Mono', monospace;

  /* size */
  --nav-height:     70px;
  --container-max:  1290px;
  --gutter:         15px;
  --section-pad:    110px;
}

/* dark tokens: overrides only (see guide §10) */
html.dark {
  --primary:         #bbdefb;
  --primary-hover:   #217ee7;
  --nav-accent:      rgba(255, 255, 255, .8);
  --text:            #f8f8f2;
  --heading:         #ffffff;
  --muted:           rgba(255, 255, 255, .54);
  --nav-text:        rgba(255, 255, 255, .85);
  --nav-text-hover:  rgba(255, 255, 255, .8);
  --nav-brand:       #ffffff;
  --bg:              #23252f;
  --bg-alt:          #272935;
  --surface:         #343a40;
  --surface-simple:  #282a36;
  --navbar-bg:       #282a36;
  --border:          #44475a;
  --card-border:     #44475a;
  --simple-border:   #44475a;
  --dropdown-border: #44475a;
  --dropdown-hover:  #3c3e4a;
  --input-bg:        #44475a;
  --input-text:      #f8f8f2;
  --input-border:    #44475a;
  --code-text:       #8be9fd;
  --code-bg:         #44475a;
  --card-text:       #f8f8f2;
  --strong-muted:    rgba(255, 255, 255, .7);
  --featurette-name: #ffffff;

  --shadow-navbar:     0 .125rem .25rem rgba(255, 255, 255, .11);
  --shadow-card:       0 2px 4px rgba(0, 0, 0, .4);
  --shadow-card-hover: 0 8px 16px rgba(0, 0, 0, .4);
  --shadow-simple:     0 1px 4px rgba(0, 0, 0, .04);
  --focus-ring:        0 0 0 .2rem rgba(33, 126, 231, .45);
}

/* ===== 3. RESET & BASE TYPOGRAPHY ===== */
*, *::before, *::after { box-sizing: border-box; }
body, h1, h2, h3, h4, h5, h6, p, ul, ol, figure, blockquote { margin: 0; }

/* Root size is responsive — 1rem is 21px on wide screens (guide §3.1) */
html {
  font-family: var(--font-body);
  font-size: 16.17px;
  line-height: 1.65;
  color: var(--text);
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
  -webkit-text-size-adjust: 100%;
}
@media screen and (min-width: 58em) {
  html { font-size: 21px; }
}

body {
  font-family: inherit;
  font-size: 1rem;
  color: inherit;
  background: var(--bg);
  margin-top: var(--nav-height);   /* room for the fixed header */
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 400;
  margin-top: 1rem;
  margin-bottom: .5rem;
  line-height: 1.25;
  color: var(--heading);
  overflow-wrap: break-word;
  hyphens: manual;
}
h1 { font-size: 2.25rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; font-weight: 700; margin-top: 1.5rem; }
h4, h5, h6 { font-size: 1rem; font-weight: 700; }

p { margin-bottom: 1rem; }
ul, ol { padding-left: 1.5rem; margin-bottom: 1rem; }
li > p { margin-bottom: 0; }

a {
  color: var(--primary);
  text-decoration: none;               /* never underlined (guide §3.6) */
  transition: color .6s ease;
}
a:hover, a:focus { color: var(--primary); text-decoration: none; }

img { max-width: 100%; height: auto; display: block; }
hr  { border: 0; height: 1px; background: var(--border); margin: 1rem 0; }

code, pre {
  font-family: var(--font-mono);
  font-size: 87.5%;
  color: var(--code-text);
  background: var(--code-bg);
}
em { font-style: italic; }

:focus-visible { outline: 2px solid var(--nav-accent); outline-offset: 2px; }

/* ===== 4. LAYOUT & GRID ===== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.row {
  display: flex;
  flex-wrap: wrap;
  margin: 0 calc(-1 * var(--gutter));
}
.row > * { padding: 0 var(--gutter); }

/* title column + content column; stacked below 992px */
.col-4, .col-8, .col-12 { flex: 0 0 100%; max-width: 100%; }
@media (min-width: 992px) {
  .col-4 { flex: 0 0 33.3333%; max-width: 33.3333%; }
  .col-8 { flex: 0 0 66.6667%; max-width: 66.6667%; }
}

/* ===== 5. HEADER & NAVIGATION TABS ===== */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1030;
  height: var(--nav-height);
  padding: 0 1rem;
  display: flex;
  align-items: center;
  background: var(--navbar-bg);
  box-shadow: var(--shadow-navbar);
  font-family: var(--font-body);
  font-size: 16.17px;                  /* px on purpose: stays compact at 21px root */
  font-weight: 400;
  line-height: 1.25;
}

.nav-inner {
  display: flex;
  align-items: center;
  width: 100%;
  padding: 0 var(--gutter);
}

/* brand */
.nav-brand {
  order: 1;
  display: inline-block;
  padding: 5px 0;
  margin-right: 1rem;
  font-size: 1.2rem;
  font-weight: 700;
  white-space: nowrap;
  color: var(--nav-brand);
  transition: none;
}
.nav-brand:hover, .nav-brand:focus { color: var(--nav-accent); text-decoration: none; }

/* tabs */
.nav-links {
  order: 2;
  display: flex;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links li { position: relative; }
.nav-links a {
  display: block;
  padding: .5rem;
  color: var(--nav-text);
  font-weight: 400;
  background: none;
  border: 0;
  border-radius: 0;
  transition: none;
  text-decoration: none;
}
.nav-links a:hover,
.nav-links a:focus { color: var(--nav-text-hover); text-decoration: none; }
.nav-links a.active {
  color: var(--nav-accent);
  font-weight: 700;
}

/* hamburger (mobile only) */
.nav-toggle {
  display: none;
  order: 0;
  position: relative;
  z-index: 1030;
  padding: .25rem 0;
  font-size: 1.125rem;
  line-height: 1;
  color: var(--nav-text-hover);
  background: transparent;
  border: 0;
  cursor: pointer;
}
html.dark .nav-toggle { color: #fff; }
.nav-toggle:focus { outline: none; box-shadow: none; }
.nav-toggle:focus-visible { outline: 2px solid var(--nav-accent); outline-offset: 2px; }

/* theme toggle + dropdown (right edge) */
.theme-dropdown { order: 3; position: relative; margin-left: auto; }
.theme-toggle {
  display: block;
  padding: .5rem 0;
  font-size: 18px;
  line-height: 1;
  color: var(--nav-text);
  background: none;
  border: 0;
  cursor: pointer;
}
.theme-toggle:hover, .theme-toggle:focus { color: var(--nav-text-hover); }

.theme-menu {
  position: absolute;
  top: 100%;
  right: 0;
  z-index: 1032;
  min-width: 10rem;
  padding: .5rem 0;
  margin: .125rem 0 0;
  background: var(--navbar-bg);
  border: 1px solid var(--dropdown-border);
  border-radius: var(--radius);
  text-align: left;
}
.theme-menu[hidden] { display: none; }
.theme-menu button {
  display: block;
  width: 100%;
  padding: .25rem 1.5rem;
  font: inherit;
  text-align: left;
  white-space: nowrap;
  color: var(--nav-text-hover);
  background: transparent;
  border: 0;
  cursor: pointer;
}
html.dark .theme-menu button { color: #fff; }
.theme-menu button:hover,
.theme-menu button:focus { background: var(--dropdown-hover); }
.theme-menu button.active { font-weight: 700; color: var(--nav-accent); }

/* ===== 6. SECTIONS ===== */
.section {
  position: relative;
  padding: var(--section-pad) 0;
  background: var(--bg);
}
.section:first-of-type { padding-top: 50px; }
.section:nth-of-type(even) { background: var(--bg-alt); }

.section-heading { display: flex; flex-direction: column; align-items: flex-start; }
.section-heading h1 { margin: 0 0 10px; }
.section-heading p  { font-size: 1.1rem; color: var(--muted); }

.section-subheading {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  margin: 1rem 0 .5rem;
  color: var(--heading);
}

/* ----- About ----- */
#about .row { align-items: flex-start; }

.profile-card { text-align: center; padding-top: 30px; padding-bottom: 30px; }

.avatar {
  display: block;
  width: 270px;
  height: 270px;
  margin: 0 auto;
  border-radius: 50%;
  object-fit: cover;
}
.profile-name {
  font-size: 1.75em;
  font-weight: 300;
  color: var(--heading);
  margin: 20px 0 10px;
}
html:not(.dark) .profile-name { color: #000; }
.profile-title, .profile-employer {
  font-size: 1rem;
  font-weight: 300;
  color: var(--muted);
  margin: 0 0 10px;
}
.profile-employer a { color: var(--primary); }

.social-icons {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  list-style: none;
  padding: 0;
  margin: 30px 0 0;
}
.social-icons li { margin-right: 10px; }
.social-icons li:last-of-type { margin-right: 0; }
.social-icons li { transition: transform .2s ease-out; }
.social-icons li:hover { transform: scale(1.2); }
.social-icons a { display: block; font-size: 2rem; line-height: 1.2; color: var(--primary); }

.bio-grid {
  display: grid;
  grid-template-columns: 5fr 7fr;
  gap: 0 var(--gutter);
  margin-top: 1rem;
}
.bio-subheading {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  margin: 1rem 0 .5rem;
  color: var(--heading);
}
.interests-list { padding-left: 1.5rem; list-style: disc; }
.interests-list li { font-size: .9rem; }

.edu-list { list-style: none; padding: 0; margin: 0; }
.edu-list li { display: flex; gap: .6rem; padding: 0 15px 4px 3px; }
.edu-list li i { color: var(--primary); margin-top: .35rem; flex-shrink: 0; }
.edu-list p { margin: 0; }
.edu-course { font-size: .9rem; }
.edu-institution { font-size: .75rem; color: var(--muted); }

/* ----- Skills (flat "featurette" tiles) ----- */
#skills .container > h1 { margin-top: 0; }
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem var(--gutter);
  margin-top: 2rem;
}
.skill-tile { text-align: center; font-size: .8rem; line-height: 1.5; color: var(--strong-muted); }
.skill-icon { font-size: 3rem; line-height: 1.25; color: var(--primary); }
.skill-name {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--featurette-name);
  margin: 0 0 5px;
}
.skill-years { margin: 0; }

/* ----- Cards (experience, accomplishments) ----- */
.exp-card, .acc-card {
  background: var(--surface);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  padding: 1.25rem;
  overflow: hidden;
  transition: all .2s ease-out;
}
.exp-card:hover, .acc-card:hover { box-shadow: var(--shadow-card-hover); }

/* experience timeline */
.timeline { list-style: none; padding: 0; margin: 0; }
.timeline-item { display: flex; gap: 1rem; }
.timeline-dot-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-shrink: 0;
  width: 1.2rem;
}
.timeline-line-top, .timeline-line-bottom { flex: 1; width: 1px; background: var(--border); }
.timeline-item:first-child .timeline-line-top,
.timeline-item:last-child  .timeline-line-bottom { background: transparent; }
.timeline-dot {
  width: .8rem;
  height: .8rem;
  margin: .5rem 0;
  border-radius: 50%;
  background: var(--primary);
  border: 1px solid var(--primary);
  flex-shrink: 0;
}
.timeline-item .exp-card { flex: 1; min-width: 0; margin: .5rem 0; }

.exp-header { display: flex; gap: .75rem; align-items: flex-start; margin-bottom: .75rem; }
.exp-logo img { width: 56px; height: 56px; object-fit: contain; }
.exp-logo-placeholder {
  width: 56px; height: 56px;
  display: flex; align-items: center; justify-content: center;
  color: var(--muted); font-size: 1.5rem;
}
.exp-header p { margin: 0; }
.exp-role {
  font-family: var(--font-heading);
  font-size: .9rem;
  font-weight: 700;
  line-height: 1.5;
  color: var(--muted);
}
.exp-company { font-family: var(--font-heading); font-size: .9rem; line-height: 1.5; color: var(--muted); }
.exp-meta { font-size: .8rem; color: var(--muted); }
.exp-meta .middot::before { content: "\00B7"; padding: 0 .45em; font-size: 15px; }
.exp-body p, .exp-body li { font-size: .75rem; color: var(--card-text); }
.exp-body ul { margin: .5rem 0 0; }

/* accomplishments */
.acc-card { display: flex; gap: 1rem; align-items: flex-start; margin-bottom: 1.5rem; }
.acc-logo img { width: 56px; height: 56px; object-fit: contain; flex-shrink: 0; }
.acc-card p { margin: 0 0 .4rem; }
.acc-title { font-family: var(--font-heading); font-size: .9rem; font-weight: 700; line-height: 1.5; }
.acc-title a { color: var(--heading); }
.acc-title a:hover { color: var(--primary); }
.acc-issuer { font-size: .8rem; color: var(--muted); }
.acc-desc { font-size: .75rem; color: var(--card-text); }

/* ----- Teaching ----- */
.teaching-institution { margin-bottom: 2rem; }
.teaching-institution h2 { margin-top: 0; font-size: 1.25rem; font-weight: 700; margin-bottom: .25rem; }
.teaching-institution .dept { color: var(--muted); font-size: .9rem; margin-bottom: .5rem; }
.teaching-institution ul { font-size: .9rem; }
.teaching-institution li { margin-bottom: .35rem; }

/* ----- Stream items (projects, talks) ----- */
.cards-list { list-style: none; padding: 0; margin: 0; }
.stream-card { display: flex; gap: 1rem; margin-bottom: 2rem; }
.stream-card:last-child { margin-bottom: 0; }
.stream-card-body { flex: 1; min-width: 0; }
.stream-card-title {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  line-height: 1.25;
  margin: 0 0 5px;
}
.stream-card-title a { color: var(--heading); }
.stream-card-title a:hover { color: var(--primary); }
.stream-card-meta { font-size: 14px; letter-spacing: .03em; color: var(--muted); margin: 0 0 5px; }
.stream-card-excerpt { font-size: .8rem; margin: 2px 0 0; }
.stream-card-thumb img { width: 150px; height: auto; object-fit: cover; flex-shrink: 0; }

/* ----- Featured publications ("simple card") ----- */
.pub-card {
  background: var(--surface-simple);
  border: 1px solid var(--simple-border);
  border-radius: var(--radius-simple);
  box-shadow: var(--shadow-simple);
  padding: 15px 20px;
  margin-top: 20px;
}
.pub-card:first-of-type { margin-top: 0; }
.pub-meta { font-size: 14px; letter-spacing: .03em; color: var(--muted); margin: 0 0 15px; }
.pub-title {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  line-height: 1.25;
  margin: 0 0 .5rem;
}
.pub-title a { color: var(--heading); }
.pub-title a:hover { color: var(--primary); }
.pub-abstract { font-size: .8rem; margin: 2px 0 1rem; }

/* ----- Recent publications list ----- */
.pub-list { list-style: none; padding: 0; margin: 0; }
.pub-list-item { display: flex; gap: .5rem; margin-bottom: 1rem; }
.pub-list-icon { color: var(--muted); font-size: .81em; margin-top: .45rem; flex-shrink: 0; }
.pub-list-item > div > a { font-weight: 700; color: var(--heading); }
.pub-list-item > div > a:hover { color: var(--primary); }
.pub-list-meta { font-size: 14px; letter-spacing: .03em; color: var(--muted); margin: .25rem 0 0; }

/* ----- Contact ----- */
.contact-info { list-style: none; padding: 0; margin: 0; }
.contact-info li { display: flex; align-items: center; gap: .75rem; padding: .25rem 0; }
.contact-info i { color: var(--primary); font-size: 1.5rem; width: 2rem; text-align: center; }

/* ===== 7. BUTTONS & TAGS ===== */
.btn-sm, .acc-link {
  display: inline-block;
  padding: 5px .5rem;
  font-size: .8rem;
  line-height: 1;
  color: var(--primary);
  background: transparent;
  border: 1px solid var(--primary);
  border-radius: var(--radius-btn);
  margin: 0 .4rem .4rem 0;
  transition: color .15s ease-in-out, background-color .15s ease-in-out, border-color .15s ease-in-out;
  text-decoration: none;
}
.btn-sm:hover, .btn-sm:focus,
.acc-link:hover, .acc-link:focus {
  color: #fff;
  background: var(--primary);
  border-color: var(--primary);
  text-decoration: none;
}
html.dark .btn-sm:hover, html.dark .acc-link:hover,
html.dark .btn-sm:focus, html.dark .acc-link:focus { color: #23252f; }
.btn-sm:focus, .acc-link:focus { box-shadow: var(--focus-ring); outline: none; }

/* ===== 8. SUB-PAGES (project / talk / publication) ===== */
.subpage-hero {
  background: var(--bg-alt);
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--border);
}
.subpage-hero h1 { margin-top: 0; font-size: 1.75rem; }   /* Wowchemy .article-title */
.subpage-meta {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem 1rem;
  font-size: 14px;
  letter-spacing: .03em;
  color: var(--muted);
  margin-bottom: .75rem;
}
.subpage-meta .tag {
  background: rgba(21, 101, 192, .1);
  color: var(--primary);
  border-radius: var(--radius);
  padding: .1rem .5rem;
  font-size: .75rem;
  letter-spacing: 0;
}
html.dark .subpage-meta .tag { background: rgba(187, 222, 251, .15); }
.subpage-body { padding: 2.5rem 0; }
.subpage-hero .container,
.subpage-body .container { max-width: 800px; }   /* 760px article + gutters, shared left edge */
.subpage-body h2 { font-size: 1.5rem; margin: 1.5rem 0 .75rem; }
.btn-actions { display: flex; flex-wrap: wrap; gap: .5rem; margin: 1.5rem 0; }
.btn-back {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  font-size: .8rem;
  color: var(--muted);
  margin-bottom: 1rem;
}
.btn-back:hover, .btn-back:focus { color: var(--primary); }

/* ===== 9. FOOTER ===== */
footer { margin: 4rem 0 0; width: 100%; padding-bottom: 2rem; color: var(--muted); }
footer p { font-size: .75rem; text-align: center; margin: 0; }

/* ===== UTILITIES ===== */
.text-muted  { color: var(--muted); }
.text-center { text-align: center; }
.italic { font-style: italic; }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: .5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mt-1 { margin-top: .5rem; }
.mt-2 { margin-top: 1rem; }

/* ===== 11. RESPONSIVE ===== */

/* < 992px: compact header, hamburger, centred brand, dropdown tab panel */
@media (max-width: 991.98px) {
  :root { --nav-height: 50px; }

  .nav-inner { padding: 0; }
  .nav-toggle { display: block; }

  .nav-brand {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    margin: 0;
    z-index: 1030;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    width: 100%;
    z-index: 1031;
    flex-direction: column;
    align-items: stretch;
    background: var(--navbar-bg);
    box-shadow: var(--shadow-navbar);
    text-align: left;
  }
  .nav-links.open { display: flex; }
  .nav-links li { padding: 10px 15px; }
  .nav-links a  { padding: 5px 15px; }

  .section-heading { align-items: center; margin-bottom: 1rem; text-align: center; }
  .bio-col h1 { text-align: center; }
}

@media (max-width: 768px) {
  .section { padding: 60px 0; }
  .section:first-of-type { padding-top: 40px; }
  .skills-grid { grid-template-columns: repeat(2, 1fr); }
  .stream-card-thumb img { max-width: 80px; }
  .bio-grid { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .skills-grid { grid-template-columns: 1fr; }
  .stream-card { flex-direction: column; }
  .subpage-hero h1 { font-size: 1.4rem; }
}

@media (max-width: 575.98px) {
  .timeline-dot-col { display: none; }
  .exp-header, .acc-card { flex-wrap: wrap; }
}

/* ===== 12. REDUCED MOTION & PRINT ===== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
  .social-icons li:hover { transform: none; }
}

@media print {
  .navbar { display: none; }
  body { margin-top: 0; }
}