/* =========================================================
   III Jornadas Científicas — ISPM
   Design system inspired by hbui.dev badges + ISPM colors
   ========================================================= */

:root {
  --primary: #0f4c81;
  --primary-600: #0d3f6b;
  --primary-50: #e8f1fb;
  --accent: #f37021;
  --accent-600: #d65b13;
  --accent-50: #fff1e6;

  --ink: #0f1729;
  --ink-2: #2b3650;
  --muted: #6b7280;
  --line: #e5e7eb;
  --bg: #ffffff;
  --bg-soft: #f7f9fc;

  --radius-sm: 8px;
  --radius: 14px;
  --radius-lg: 22px;

  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.06);
  --shadow: 0 10px 30px -10px rgba(15, 76, 129, 0.18);
  --shadow-lg: 0 30px 60px -25px rgba(15, 76, 129, 0.35);

  --ff-sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --ff-display: "Plus Jakarta Sans", "Inter", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--ff-sans);
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  line-height: 1.6;
}

a { color: var(--primary); text-decoration: none; transition: color .2s; }
a:hover { color: var(--accent); }

img { max-width: 100%; }

.text-accent { color: var(--accent); }

/* =========================================================
   Topbar
   ========================================================= */
.topbar {
  background: var(--ink);
  color: #cbd5e1;
  font-size: 0.82rem;
  padding: 8px 0;
}
.topbar i { color: var(--accent); margin-right: 4px; }
.topbar-right span { margin-left: 8px; }

/* =========================================================
   Navbar
   ========================================================= */
.main-nav {
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid rgba(15, 76, 129, 0.08);
  padding: 14px 0;
  transition: padding .2s, box-shadow .2s;
}
.main-nav.scrolled {
  padding: 10px 0;
  box-shadow: var(--shadow-sm);
}
.navbar-brand { gap: 10px; }
.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  font-family: var(--ff-display);
  font-weight: 800;
  font-size: 0.95rem;
  letter-spacing: 0.5px;
  box-shadow: 0 8px 18px -8px rgba(243, 112, 33, 0.6);
}
.brand-text {
  display: flex;
  flex-direction: column;
  font-family: var(--ff-display);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--ink);
  line-height: 1.1;
}
.brand-text small {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--muted);
  letter-spacing: 0.4px;
}

.nav-link {
  color: var(--ink-2) !important;
  font-weight: 500;
  padding: 8px 14px !important;
  border-radius: 8px;
  transition: all .2s;
}
.nav-link:hover, .nav-link.active {
  color: var(--primary) !important;
  background: var(--primary-50);
}

/* =========================================================
   Buttons
   ========================================================= */
.btn-cta {
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  padding: 10px 20px;
  border-radius: 10px;
  border: 1px solid var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: all .25s;
  box-shadow: 0 8px 20px -10px rgba(243, 112, 33, 0.65);
}
.btn-cta:hover {
  background: var(--accent-600);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 14px 26px -10px rgba(243, 112, 33, 0.7);
}
.btn-cta.btn-lg { padding: 14px 24px; font-size: 1rem; }
.btn-cta.btn-sm { padding: 7px 14px; font-size: 0.85rem; }

.btn-ghost {
  background: transparent;
  color: var(--primary);
  border: 1.5px solid rgba(15, 76, 129, 0.18);
  font-weight: 600;
  padding: 12px 22px;
  border-radius: 10px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: all .25s;
}
.btn-ghost:hover {
  background: var(--primary-50);
  border-color: var(--primary);
  color: var(--primary-600);
}

/* =========================================================
   HBUI-style Badges
   (replicates the look from hbui.dev/docs/components/badges)
   ========================================================= */
.hbui-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  font-size: 0.75rem;
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: 0.2px;
  border-radius: 999px;
  border: 1px solid transparent;
  white-space: nowrap;
  transition: transform .15s, box-shadow .15s;
}
.hbui-badge i { font-size: 0.85rem; }

.hbui-badge-default {
  background: var(--ink);
  color: #fff;
}
.hbui-badge-secondary {
  background: #eef2f7;
  color: var(--ink-2);
}
.hbui-badge-destructive {
  background: #ef4444;
  color: #fff;
}
.hbui-badge-success {
  background: #10b981;
  color: #fff;
}
.hbui-badge-warning {
  background: var(--accent);
  color: #fff;
}
.hbui-badge-outline {
  background: transparent;
  border-color: rgba(15, 23, 41, 0.18);
  color: var(--ink-2);
}
.hbui-badge-outline-soft {
  background: var(--primary-50);
  color: var(--primary);
  border-color: rgba(15, 76, 129, 0.15);
}
.hbui-badge-room {
  background: linear-gradient(135deg, var(--primary), var(--primary-600));
  color: #fff;
  font-family: var(--ff-display);
  font-weight: 700;
  letter-spacing: 0.4px;
}

.hbui-badge .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.35);
  animation: pulse 1.6s infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* =========================================================
   Hero
   ========================================================= */
.hero {
  position: relative;
  padding: 80px 0 100px;
  overflow: hidden;
  background: linear-gradient(180deg, #f7faff 0%, #ffffff 100%);
}
.hero-bg {
  position: absolute;
  top: -200px;
  right: -200px;
  width: 700px;
  height: 700px;
  background: radial-gradient(circle, rgba(243, 112, 33, 0.18), transparent 60%);
  filter: blur(20px);
  z-index: 0;
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(15, 76, 129, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(15, 76, 129, 0.05) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(circle at 70% 20%, black, transparent 70%);
  -webkit-mask-image: radial-gradient(circle at 70% 20%, black, transparent 70%);
  z-index: 0;
}
.hero-inner { position: relative; z-index: 1; }

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.hero-title {
  font-family: var(--ff-display);
  font-size: clamp(2.2rem, 4.5vw, 3.6rem);
  line-height: 1.05;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.5px;
}
.hero-sub {
  display: block;
  margin-top: 14px;
  font-size: clamp(0.95rem, 1.4vw, 1.05rem);
  font-weight: 500;
  color: var(--ink-2);
  font-family: var(--ff-sans);
  text-transform: uppercase;
  letter-spacing: 1.2px;
}
.hero-lead {
  font-size: 1.08rem;
  color: var(--ink-2);
  margin: 22px 0 28px;
  max-width: 560px;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 18px 28px;
  margin-top: 18px;
}
.hero-meta-item {
  display: flex;
  gap: 12px;
  align-items: center;
}
.hero-meta-item i {
  width: 42px; height: 42px;
  background: var(--primary-50);
  color: var(--primary);
  border-radius: 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}
.hero-meta-item .meta-label {
  display: block;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--muted);
}
.hero-meta-item strong {
  color: var(--ink);
  font-weight: 700;
  font-size: 1rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* Hero floating card */
.hero-card {
  position: relative;
  background: #fff;
  border: 1px solid rgba(15, 76, 129, 0.1);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-lg);
  transform: translateY(0);
  transition: transform .35s ease;
}
.hero-card::before {
  content: "";
  position: absolute;
  inset: -2px;
  border-radius: var(--radius-lg);
  padding: 2px;
  background: linear-gradient(135deg, rgba(15, 76, 129, 0.4), rgba(243, 112, 33, 0.4));
  -webkit-mask:
    linear-gradient(#000 0 0) content-box,
    linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
          mask-composite: exclude;
  pointer-events: none;
  opacity: 0.3;
}
.hero-card:hover { transform: translateY(-4px); }

.hero-card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}
.hero-card-time {
  font-family: var(--ff-display);
  font-weight: 700;
  color: var(--ink);
  font-size: 0.9rem;
}
.hero-card-title {
  font-family: var(--ff-display);
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 6px;
}
.hero-card-author {
  color: var(--ink-2);
  margin: 0;
}
.hero-card-author i { color: var(--accent); margin-right: 6px; }
.hero-card hr { margin: 16px 0; opacity: 0.18; }

.hero-card-list {
  list-style: none;
  padding: 0;
  margin: 0 0 18px;
  display: grid;
  gap: 10px;
}
.hero-card-list li {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.95rem;
  color: var(--ink-2);
}
.hero-card-list i { color: #10b981; font-size: 1.1rem; }

/* =========================================================
   Stats
   ========================================================= */
.stats {
  margin-top: -40px;
  position: relative;
  z-index: 2;
  padding-bottom: 30px;
}
.stat-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: transform .25s, box-shadow .25s;
  height: 100%;
}
.stat-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
  border-color: rgba(15, 76, 129, 0.2);
}
.stat-num {
  display: block;
  font-family: var(--ff-display);
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
}
.stat-label {
  display: block;
  margin-top: 6px;
  font-size: 0.85rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* =========================================================
   Sections
   ========================================================= */
.section { padding: 90px 0; }
.section-alt { background: var(--bg-soft); }

.section-eyebrow {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--accent);
  margin-bottom: 10px;
}
.section-title {
  font-family: var(--ff-display);
  font-weight: 800;
  font-size: clamp(1.8rem, 3.2vw, 2.6rem);
  color: var(--ink);
  letter-spacing: -0.3px;
  line-height: 1.15;
}
.section-lead {
  font-size: 1.05rem;
  color: var(--ink-2);
  margin-top: 14px;
}

/* =========================================================
   About
   ========================================================= */
.about-features {
  display: grid;
  gap: 18px;
  margin-top: 28px;
}
.about-feature {
  display: flex;
  gap: 14px;
  padding: 16px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: all .25s;
}
.about-feature:hover {
  border-color: rgba(15, 76, 129, 0.2);
  box-shadow: var(--shadow-sm);
  transform: translateX(3px);
}
.about-icon {
  flex-shrink: 0;
  width: 44px; height: 44px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary-50), #fff);
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  border: 1px solid rgba(15, 76, 129, 0.12);
}
.about-feature h5 {
  font-family: var(--ff-display);
  font-weight: 700;
  margin: 0 0 4px;
  color: var(--ink);
  font-size: 1rem;
}
.about-feature p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.about-visual {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  position: relative;
}
.about-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: all .3s;
}
.about-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}
.about-card h4 {
  font-family: var(--ff-display);
  font-weight: 700;
  margin: 14px 0 6px;
  font-size: 1.1rem;
  color: var(--ink);
}
.about-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}
.about-card-1 { grid-column: 1 / 2; transform: translateY(20px); }
.about-card-2 { grid-column: 2 / 3; }
.about-card-3 { grid-column: 1 / -1; }

@media (max-width: 575px) {
  .about-visual { grid-template-columns: 1fr; }
  .about-card-1 { grid-column: auto; transform: none; }
  .about-card-2, .about-card-3 { grid-column: auto; }
}

/* =========================================================
   Timeline
   ========================================================= */
.timeline {
  position: relative;
  max-width: 880px;
  margin: 0 auto;
  padding-left: 40px;
}
.timeline::before {
  content: "";
  position: absolute;
  top: 10px;
  bottom: 10px;
  left: 18px;
  width: 2px;
  background: linear-gradient(180deg, var(--primary), var(--accent));
  border-radius: 2px;
}
.timeline-item {
  position: relative;
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: 20px;
  margin-bottom: 22px;
  align-items: start;
}
.timeline-item::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 14px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: #fff;
  border: 3px solid var(--primary);
  box-shadow: 0 0 0 4px rgba(15, 76, 129, 0.1);
}
.timeline-item.highlight::before {
  border-color: var(--accent);
  box-shadow: 0 0 0 6px rgba(243, 112, 33, 0.18);
  animation: pulse 1.8s infinite;
}
.timeline-time {
  font-family: var(--ff-display);
  font-weight: 700;
  color: var(--primary);
  font-size: 0.95rem;
  background: var(--primary-50);
  padding: 8px 12px;
  border-radius: 8px;
  text-align: center;
  height: fit-content;
}
.timeline-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 22px;
  box-shadow: var(--shadow-sm);
  transition: all .25s;
}
.timeline-card:hover {
  border-color: rgba(15, 76, 129, 0.2);
  box-shadow: var(--shadow);
  transform: translateX(4px);
}
.timeline-card h4 {
  font-family: var(--ff-display);
  font-weight: 700;
  margin: 8px 0 6px;
  color: var(--ink);
  font-size: 1.1rem;
}
.timeline-card p {
  margin: 4px 0;
  color: var(--ink-2);
  font-size: 0.94rem;
}
.timeline-card p i { color: var(--accent); margin-right: 4px; }

.timeline-item.highlight .timeline-card {
  background: linear-gradient(135deg, #fff, var(--accent-50));
  border-color: rgba(243, 112, 33, 0.3);
}
.timeline-item.bigblock .timeline-card {
  background: linear-gradient(135deg, var(--primary-50), #fff);
  border-color: rgba(15, 76, 129, 0.2);
}

@media (max-width: 575px) {
  .timeline { padding-left: 30px; }
  .timeline::before { left: 10px; }
  .timeline-item { grid-template-columns: 1fr; gap: 8px; }
  .timeline-item::before { left: -22px; }
  .timeline-time { width: fit-content; }
}

/* =========================================================
   Filters
   ========================================================= */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
  justify-content: space-between;
  padding: 18px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 16px;
  box-shadow: var(--shadow-sm);
}
.search-wrap {
  position: relative;
  flex: 1 1 280px;
  max-width: 420px;
}
.search-wrap i {
  position: absolute;
  top: 50%;
  left: 14px;
  transform: translateY(-50%);
  color: var(--muted);
}
.search-wrap input.form-control {
  padding: 10px 14px 10px 40px;
  border-radius: 10px;
  border: 1px solid var(--line);
  font-size: 0.95rem;
}
.search-wrap input.form-control:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(15, 76, 129, 0.12);
}

.filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.chip {
  background: var(--bg-soft);
  border: 1px solid var(--line);
  color: var(--ink-2);
  padding: 7px 14px;
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: 999px;
  cursor: pointer;
  transition: all .2s;
}
.chip:hover { border-color: var(--primary); color: var(--primary); }
.chip.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
  box-shadow: 0 6px 14px -6px rgba(15, 76, 129, 0.5);
}

.result-count {
  font-size: 0.88rem;
}

/* =========================================================
   Battery / Talk cards
   ========================================================= */
.battery-block {
  margin-bottom: 56px;
}
.battery-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 22px;
  padding-bottom: 14px;
  border-bottom: 2px dashed rgba(15, 76, 129, 0.15);
}
.battery-title {
  font-family: var(--ff-display);
  font-weight: 800;
  color: var(--ink);
  margin: 8px 0 0;
  font-size: 1.4rem;
  letter-spacing: -0.2px;
}
.battery-count {
  background: var(--accent-50);
  color: var(--accent-600);
  font-weight: 700;
  font-size: 0.85rem;
  padding: 6px 14px;
  border-radius: 999px;
}

.talk-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  height: 100%;
  display: flex;
  flex-direction: column;
  transition: all .3s ease;
  position: relative;
  overflow: hidden;
}
.talk-card::after {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 0;
  background: linear-gradient(180deg, var(--primary), var(--accent));
  transition: height .3s;
}
.talk-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
  border-color: rgba(15, 76, 129, 0.2);
}
.talk-card:hover::after { height: 100%; }

.talk-card header {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 14px;
}
.talk-title {
  font-family: var(--ff-display);
  font-weight: 700;
  color: var(--ink);
  font-size: 1rem;
  line-height: 1.4;
  margin: 0 0 16px;
  flex: 1;
}
.talk-meta {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 8px;
  border-top: 1px solid var(--line);
  padding-top: 14px;
}
.talk-meta li {
  font-size: 0.86rem;
  color: var(--ink-2);
  display: flex;
  align-items: flex-start;
  gap: 8px;
}
.talk-meta li i {
  color: var(--accent);
  margin-top: 3px;
  flex-shrink: 0;
}
.talk-meta strong { color: var(--ink); }

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--muted);
}
.empty-state i {
  font-size: 3rem;
  color: var(--primary);
  opacity: 0.3;
  margin-bottom: 16px;
  display: block;
}
.empty-state h4 { color: var(--ink); margin-bottom: 6px; }

/* =========================================================
   Closing
   ========================================================= */
.closing-card {
  background: linear-gradient(135deg, #fff 0%, var(--primary-50) 100%);
  border: 1px solid rgba(15, 76, 129, 0.15);
  border-radius: var(--radius-lg);
  padding: 44px;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}
.closing-card::before {
  content: "";
  position: absolute;
  top: -100px; right: -100px;
  width: 300px; height: 300px;
  background: radial-gradient(circle, rgba(243, 112, 33, 0.15), transparent 70%);
  pointer-events: none;
}

.closing-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
.closing-tile {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
  text-align: center;
  transition: all .25s;
}
.closing-tile:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-sm);
}
.closing-tile i {
  font-size: 1.5rem;
  color: var(--accent);
  display: block;
  margin-bottom: 8px;
}
.closing-tile strong {
  display: block;
  font-family: var(--ff-display);
  color: var(--ink);
  font-size: 0.95rem;
}
.closing-tile span {
  display: block;
  font-size: 0.82rem;
  color: var(--muted);
  margin-top: 2px;
}

@media (max-width: 575px) {
  .closing-card { padding: 28px; }
}

/* =========================================================
   Footer
   ========================================================= */
.footer {
  background: var(--ink);
  color: #cbd5e1;
  padding: 60px 0 28px;
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}
.footer-brand strong {
  display: block;
  font-family: var(--ff-display);
  color: #fff;
  font-size: 1.05rem;
}
.footer-brand small {
  display: block;
  font-size: 0.8rem;
  opacity: 0.7;
}
.footer-text {
  font-size: 0.92rem;
  color: #94a3b8;
  max-width: 420px;
}
.footer-badges {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 12px;
}
.footer-badges .hbui-badge-outline {
  border-color: rgba(255, 255, 255, 0.2);
  color: #cbd5e1;
}

.footer-title {
  font-family: var(--ff-display);
  color: #fff;
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 14px;
  text-transform: uppercase;
  letter-spacing: 1.2px;
}
.footer-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 8px;
}
.footer-list a {
  color: #94a3b8;
  font-size: 0.92rem;
  transition: color .2s, padding-left .2s;
}
.footer-list a:hover {
  color: var(--accent);
  padding-left: 4px;
}
.footer-list li i {
  color: var(--accent);
  margin-right: 8px;
}
.footer-sep {
  border-color: rgba(255, 255, 255, 0.08);
  margin: 30px 0 18px;
}
.footer small { color: #94a3b8; }

/* =========================================================
   Back to top
   ========================================================= */
.back-to-top {
  position: fixed;
  bottom: 26px;
  right: 26px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: none;
  background: var(--primary);
  color: #fff;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow);
  opacity: 0;
  transform: translateY(20px);
  transition: all .3s;
  z-index: 999;
  cursor: pointer;
}
.back-to-top:hover {
  background: var(--accent);
  transform: translateY(-3px);
}
.back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
}

/* =========================================================
   Animations
   ========================================================= */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity .6s ease, transform .6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* responsive tweaks */
@media (max-width: 991px) {
  .hero { padding: 60px 0 70px; }
  .stats { margin-top: 0; padding-top: 30px; }
  .section { padding: 70px 0; }
  .hero-card { margin-top: 40px; }
}