/*
  MTFL Shared Styles
  ==================
  Used by all pages. Import via: <link href="css/mtfl.css" rel="stylesheet">

  FONTS — Northeastern's official typeface is FF Real (Real Head Pro).
  If you get the web license, update --font-heading and --font-body below.
  Until then: Libre Baskerville (headings) + Lato (body, NEU-approved alternative).
  See: brand.northeastern.edu/design-and-experiences/typography
*/

/* === VARIABLES === */
:root {
  /* Colors */
  --clr-bg:           #faf9f7;
  --clr-surface:      #ffffff;
  --clr-text:         #1a1a1a;
  --clr-text-muted:   #5c5c5c;
  --clr-accent:       #8b2332;
  --clr-accent-light: #a83a4a;
  --clr-border:       #e4e0db;
  --clr-nav-bg:       #1a1a1a;
  --clr-nav-text:     #f0ece6;
  --clr-footer-bg:    #111111;
  --clr-footer-text:  #a0a0a0;
  --clr-tag-bg:       #f2eeea;

  /* Typography — to swap to FF Real, change these two lines */
  --font-heading: 'Libre Baskerville', Georgia, serif;
  --font-body:    'Lato', 'Segoe UI', sans-serif;

  /* Spacing */
  --space-xs:  0.5rem;
  --space-sm:  1rem;
  --space-md:  1.5rem;
  --space-lg:  2.5rem;
  --space-xl:  4rem;
  --space-2xl: 6rem;

  /* Layout */
  --max-width: 1140px;
  --radius:    8px;
  --radius-lg: 12px;

  /* Motion */
  --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

/* === RESET === */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  color: var(--clr-text);
  background: var(--clr-bg);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--clr-accent);
  text-decoration: none;
  transition: color 0.2s var(--ease);
}
a:hover { color: var(--clr-accent-light); }

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* === NAV === */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--clr-bg);
  border-bottom: 1px solid var(--clr-border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo img { height: 36px; width: auto; }

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--space-xs);
}

.nav-links a {
  color: var(--clr-text);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius);
  transition: background 0.2s var(--ease), color 0.2s var(--ease);
  letter-spacing: 0.01em;
}

.nav-links a:hover {
  background: rgba(0,0,0,0.05);
  color: var(--clr-text);
}

.nav-links a.active {
  background: var(--clr-accent);
  color: #fff;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--clr-text);
  margin: 5px 0;
  border-radius: 2px;
}

/* === BREADCRUMB === */
.breadcrumb-bar {
  background: var(--clr-nav-bg);
  border-bottom: none;
  padding: var(--space-sm) 0;
  font-size: 0.95rem;
  color: rgba(255,255,255,0.7);
  text-align: center;
}

.breadcrumb-bar a { color: rgba(255,255,255,0.85); }
.breadcrumb-bar a:hover { color: #fff; }
.breadcrumb-bar span { margin: 0 0.4rem; opacity: 0.5; }

/* === PAGE HEADER === */
.page-header {
  text-align: center;
  padding: var(--space-xl) 0 var(--space-lg);
}

.page-header h1 {
  font-family: var(--font-heading);
  font-size: clamp(2.4rem, 5vw, 3.4rem);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--clr-text);
}

.header-rule {
  width: 48px;
  height: 3px;
  background: var(--clr-accent);
  border: none;
  margin: 0.6rem auto 0;
  border-radius: 2px;
}

/* === SECTION TITLES === */
.section-title {
  font-family: var(--font-heading);
  font-size: clamp(1.6rem, 3vw, 2rem);
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-md);
}

/* === FOOTER === */
.site-footer {
  background: var(--clr-footer-bg);
  color: var(--clr-footer-text);
  padding: var(--space-lg) 0;
}

.footer-inner {
  display: flex;
  justify-content: center;
  align-items: start;
  flex-wrap: wrap;
  gap: var(--space-lg);
}

.footer-links { text-align: center; }

.footer-links h4 {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  color: #e0ddd8;
  margin-bottom: var(--space-sm);
  font-weight: 600;
}

.footer-links ul { list-style: none; }
.footer-links li { margin-bottom: 0.4rem; }
.footer-links a { color: var(--clr-footer-text); font-size: 0.88rem; }
.footer-links a:hover { color: #fff; }

.footer-copy {
  width: 100%;
  text-align: center;
  padding-top: var(--space-md);
  margin-top: var(--space-md);
  border-top: 1px solid rgba(255,255,255,0.08);
  font-size: 0.82rem;
}

/* === RESPONSIVE === */
@media (max-width: 1200px) {
  .container { padding: 0 5%; }
}

@media (max-width: 680px) {
  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--clr-bg);
    padding: var(--space-sm) var(--space-md) var(--space-md);
    border-bottom: 1px solid var(--clr-border);
    gap: 0.25rem;
  }

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

/* === ANIMATIONS === */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

.fade-up { animation: fadeUp 0.5s var(--ease) both; }
.fade-up-d1 { animation-delay: 0.08s; }
.fade-up-d2 { animation-delay: 0.16s; }
.fade-up-d3 { animation-delay: 0.24s; }