/* ============================================================
   DexaFit Research — Shared Design System
   Fonts: DM Serif Display (headlines) + DM Sans (body/UI) + Roboto Mono (data)
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,300;1,9..40,400&family=DM+Serif+Display&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Roboto+Mono:wght@400;500;600&display=swap');

/* ── TOKENS ────────────────────────────────────────────────── */
:root {
  --blue:        #46A5FC;
  --blue-hover:  #2D8DE0;
  --blue-tint:   #E8F2FF;
  --blue-soft:   #F5F9FF;
  --blue-glow:   rgba(70,165,252,0.28);

  --dark:        #0C0F14;
  --dark-2:      #141820;
  --dark-3:      #1C2230;

  --white:       #FFFFFF;
  --section:     #F7F8FA;
  --section-2:   #F0F1F4;

  --ink:         #1E1E1E;
  --muted:       #525252;
  --faint:       #888888;
  --line:        rgba(0,0,0,0.08);
  --dark-line:   rgba(255,255,255,0.09);

  --sans:   'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --mono:   'Roboto Mono', ui-monospace, 'SF Mono', monospace;
  --serif:  'DM Serif Display', Georgia, serif;

  --r-sm:   9px;
  --r-md:   12px;
  --r-lg:   14px;
  --r-xl:   20px;
  --r-pill: 999px;

  --shadow-card:  0 6px 24px rgba(0,0,0,0.07);
  --shadow-lift:  0 12px 32px rgba(0,0,0,0.11);
  --shadow-blue:  0 8px 20px rgba(70,165,252,0.28);
  --shadow-nav:   0 4px 24px rgba(0,0,0,0.09);

  --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* ── RESET ─────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--sans);
  background: var(--white);
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  line-height: 1.6;
}
::selection { background: var(--blue); color: #fff; }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: none; }
img, svg { display: block; max-width: 100%; }
button { font-family: inherit; cursor: pointer; border: none; }
h1, h2 { font-family: var(--serif); }

/* ── SCROLL PROGRESS ────────────────────────────────────────── */
#progress {
  position: fixed; top: 0; left: 0;
  height: 2px; background: var(--blue);
  width: 0%; z-index: 2000;
  transition: width 0.1s linear;
}

/* ── TOP NAV BAR ────────────────────────────────────────────── */
.site-nav {
  position: fixed; top: 0; left: 0; right: 0;
  z-index: 1000;
}
.nav-pill {
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--line);
  padding: 0 48px;
  display: flex; align-items: center; justify-content: space-between;
  height: 70px; gap: 12px;
}
.nav-brand {
  display: flex; align-items: center; gap: 8px;
  text-decoration: none; flex-shrink: 0;
}
.nav-bug { width: 15px; height: 15px; }
.nav-logo { height: 42px; width: auto; display: block; }
.nav-brand-text {
  font-size: 12px; font-weight: 800;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--ink); white-space: nowrap;
}
.nav-brand-text .accent { color: var(--blue); }
.nav-links {
  display: flex; gap: 0; align-items: center; flex: 1; justify-content: center;
}
.nav-links a {
  font-family: var(--serif); font-size: 15px; font-weight: 400;
  letter-spacing: 0.01em; text-transform: none;
  color: var(--muted); padding: 0 16px; height: 70px;
  display: flex; align-items: center;
  border-bottom: 2px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
  white-space: nowrap;
}
.nav-links a:hover { color: var(--ink); }
.nav-links a.active { color: var(--blue); border-bottom-color: var(--blue); }
.nav-cta {
  background: var(--blue); color: #fff !important;
  padding: 10px 22px; border-radius: var(--r-pill);
  font-family: var(--serif); font-size: 15px; font-weight: 400;
  letter-spacing: 0.01em; text-transform: none;
  transition: background 0.2s var(--ease), box-shadow 0.2s var(--ease);
  white-space: nowrap; flex-shrink: 0;
}
.nav-cta:hover {
  background: var(--blue-hover);
  box-shadow: var(--shadow-blue);
}

/* ── SCROLL REVEAL ──────────────────────────────────────────── */
.reveal {
  opacity: 0; transform: translateY(24px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.reveal.visible { opacity: 1; transform: translateY(0); }
.d1 { transition-delay: 0.1s; }
.d2 { transition-delay: 0.2s; }
.d3 { transition-delay: 0.3s; }
.d4 { transition-delay: 0.4s; }
.d5 { transition-delay: 0.5s; }

/* ── EYEBROW ────────────────────────────────────────────────── */
.eyebrow {
  font-size: 11px; font-weight: 700;
  letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--blue); display: flex; align-items: center; gap: 8px;
}
.eyebrow::before {
  content: ''; display: block;
  width: 20px; height: 2px; background: var(--blue);
  border-radius: 2px; flex-shrink: 0;
}

/* ── BADGES ─────────────────────────────────────────────────── */
.badge {
  display: inline-flex; align-items: center; gap: 5px;
  padding: 4px 10px; border-radius: var(--r-pill);
  font-size: 10px; font-weight: 700;
  letter-spacing: 0.08em; text-transform: uppercase;
  white-space: nowrap;
}
.badge-research { background: #E8F4FF; color: #2B8BE6; }
.badge-reference { background: #E8F9F0; color: #0C8A56; }
.badge-note      { background: #F0ECFF; color: #5B47CC; }
.badge-curated   { background: #FFF3E8; color: #C47A20; }
.badge-review    { background: #FFE8E8; color: #CC4747; }

/* ── BUTTONS ────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 24px; border-radius: var(--r-pill);
  font-family: var(--sans); font-size: 13px; font-weight: 700;
  letter-spacing: 0.06em; text-transform: uppercase;
  border: none; cursor: pointer;
  transition: all 0.22s var(--ease);
  white-space: nowrap;
}
.btn-primary {
  background: var(--blue); color: #fff;
  box-shadow: 0 4px 14px rgba(70,165,252,0.2);
}
.btn-primary:hover {
  background: var(--blue-hover); transform: translateY(-1px);
  box-shadow: var(--shadow-blue);
}
.btn-ghost-white {
  background: transparent; color: rgba(255,255,255,0.8);
  border: 1.5px solid rgba(255,255,255,0.25);
}
.btn-ghost-white:hover {
  border-color: rgba(255,255,255,0.6); color: #fff;
  background: rgba(255,255,255,0.07);
}
.btn-ghost {
  background: transparent; color: var(--blue);
  border: 1.5px solid rgba(70,165,252,0.35);
}
.btn-ghost:hover {
  border-color: var(--blue); background: var(--blue-tint);
}

/* ── CARD ───────────────────────────────────────────────────── */
.card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  box-shadow: var(--shadow-card);
  padding: 28px;
  transition: transform 0.22s var(--ease), box-shadow 0.22s var(--ease), border-color 0.22s;
}
.card:hover {
  transform: translateY(-3px); box-shadow: var(--shadow-lift);
  border-color: rgba(70,165,252,0.3);
}

/* ── SECTION LAYOUT ─────────────────────────────────────────── */
.container {
  max-width: 1100px;
  margin-left: auto; margin-right: auto;
  padding-left: 48px; padding-right: 48px;
}
section { position: relative; }

/* ── FOOTER ─────────────────────────────────────────────────── */
.site-footer {
  background: var(--dark);
  padding: 72px 48px 40px;
}
.footer-inner { max-width: 1100px; margin: 0 auto; }
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px; padding-bottom: 48px;
  border-bottom: 1px solid var(--dark-line); margin-bottom: 32px;
}
.footer-col h4 {
  font-size: 10px; font-weight: 700;
  letter-spacing: 0.15em; text-transform: uppercase;
  color: rgba(255,255,255,0.3); margin-bottom: 16px;
}
.footer-col a, .footer-col p {
  display: block; font-size: 14px;
  color: rgba(255,255,255,0.5); margin-bottom: 10px;
  line-height: 1.65;
  transition: color 0.2s;
}
.footer-col a:hover { color: rgba(255,255,255,0.9); }
.footer-bottom {
  display: flex; justify-content: space-between; align-items: center;
}
.footer-brand-row {
  display: flex; align-items: center; gap: 10px;
}
.footer-logo-sm { height: 22px; width: auto; opacity: 0.75; }
.footer-copy { font-size: 12px; color: rgba(255,255,255,0.25); }

/* ── ARTICLE CARD (list item) ───────────────────────────────── */
.article-row {
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  display: flex; flex-direction: column; gap: 6px;
  cursor: pointer;
  transition: padding-left 0.2s var(--ease);
}
.article-row:hover { padding-left: 6px; }
.article-row:hover .article-row-title { color: var(--blue); }
.article-row-meta {
  display: flex; align-items: center; gap: 10px;
  flex-wrap: wrap;
}
.article-row-topic {
  font-size: 11px; color: var(--faint); font-weight: 500;
  letter-spacing: 0.04em;
}
.article-row-title {
  font-size: 16px; font-weight: 700;
  color: var(--ink); line-height: 1.35;
  transition: color 0.2s;
}
.article-row-source {
  font-size: 12px; color: var(--blue); font-weight: 500;
}

/* ── MODAL ──────────────────────────────────────────────────── */
.df-modal-overlay {
  display: none; position: fixed; inset: 0; z-index: 9999;
  background: rgba(0,0,0,0.5); align-items: center; justify-content: center;
}
.df-modal-overlay.open { display: flex; }
.df-modal {
  background: #fff; border-radius: var(--r-xl);
  padding: 48px 40px 40px; max-width: 420px; width: 90%;
  text-align: center; position: relative;
  box-shadow: 0 24px 60px rgba(0,0,0,0.2);
  animation: dfIn 0.3s var(--ease);
}
@keyframes dfIn {
  from { opacity: 0; transform: translateY(16px) scale(0.97); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}
.df-modal-icon {
  width: 52px; height: 52px; border-radius: 50%;
  background: var(--blue-tint); display: flex;
  align-items: center; justify-content: center; margin: 0 auto 18px;
}
.df-modal-title {
  font-family: var(--serif); font-size: 22px; color: var(--ink);
  margin-bottom: 10px; line-height: 1.2;
}
.df-modal-body {
  font-size: 15px; color: var(--muted); line-height: 1.6; margin-bottom: 28px;
}
.df-modal-close {
  font-size: 13px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--blue); background: none; border: 1.5px solid var(--blue);
  border-radius: var(--r-pill); padding: 10px 28px;
  transition: all 0.2s;
}
.df-modal-close:hover { background: var(--blue); color: #fff; }

/* ── FORM ───────────────────────────────────────────────────── */
.form-field input,
.form-field select,
.form-field textarea {
  width: 100%; padding: 13px 16px;
  border: 1px solid rgba(0,0,0,0.12); border-radius: var(--r-md);
  font-size: 15px; font-family: var(--sans); background: #fff; color: var(--ink);
  transition: border-color 0.2s, box-shadow 0.2s;
}
.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
  outline: none; border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(70,165,252,0.1);
}
.form-field textarea { resize: vertical; min-height: 120px; }

/* ── ARTICLE THUMBNAIL ──────────────────────────────────────── */
.article-thumb {
  width: 88px; height: 66px; flex-shrink: 0;
  background: var(--section);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
  display: flex; align-items: center; justify-content: center;
}
.article-thumb svg { width: 24px; height: 24px; color: var(--faint); opacity: 0.5; }

/* ── RESPONSIVE ─────────────────────────────────────────────── */
@media (max-width: 900px) {
  .container { padding-left: 28px; padding-right: 28px; }
  .nav-pill { padding: 0 28px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
}
@media (max-width: 600px) {
  .nav-pill { padding: 0 16px; }
  .nav-links { display: none; }
  .container { padding-left: 20px; padding-right: 20px; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .footer-bottom { flex-direction: column; gap: 10px; text-align: center; }
  .site-footer { padding: 56px 20px 32px; }
  .article-thumb { display: none; }
  .filter-row { overflow-x: auto; flex-wrap: nowrap; -webkit-overflow-scrolling: touch; padding-bottom: 4px; }
  .filter-row::-webkit-scrollbar { display: none; }
}