@import url('https://fonts.googleapis.com/css2?family=Orbitron:wght@400;600;700;900&family=Sora:wght@300;400;500;600&display=swap');

/* VARIÁVEIS — MODO DIA */
:root {
  --bg:           #f0f2f5;
  --bg-alt:       #e4e8ef;
  --bg-card:      #ffffff;
  --text:         #0d1117;
  --text-muted:   #5a6478;
  --accent:       #00c2a8;
  --accent2:      #0077ff;
  --accent-glow:  rgba(0,194,168,0.25);
  --border:       #d0d7e3;
  --nav-bg:       rgba(240,242,245,0.92);
  --hero-overlay: rgba(240,242,245,0.55);
  --card-shadow:  0 4px 32px rgba(0,0,0,0.08);
  --card-hover:   0 12px 48px rgba(0,194,168,0.18);
  --tag-bg:       #e0faf6;
  --tag-text:     #007a6a;
  --footer-bg:    #0d1117;
  --footer-text:  #8899aa;
  --section-num:  rgba(0,194,168,0.08);
  --btn-text:     #ffffff;
  --diff-ev-bg:   #e8f8f5;
  --diff-ice-bg:  #fff3e0;
}

/* VARIÁVEIS — MODO NOITE */
[data-theme="night"] {
  --bg:           #080c12;
  --bg-alt:       #0d1420;
  --bg-card:      #111928;
  --text:         #e8edf5;
  --text-muted:   #7a8ba0;
  --accent:       #00e5c8;
  --accent2:      #3d9eff;
  --accent-glow:  rgba(0,229,200,0.2);
  --border:       #1e2d40;
  --nav-bg:       rgba(8,12,18,0.95);
  --hero-overlay: rgba(8,12,18,0.6);
  --card-shadow:  0 4px 32px rgba(0,0,0,0.5);
  --card-hover:   0 12px 48px rgba(0,229,200,0.15);
  --tag-bg:       rgba(0,229,200,0.1);
  --tag-text:     #00e5c8;
  --footer-bg:    #050810;
  --footer-text:  #4a5a6a;
  --section-num:  rgba(0,229,200,0.06);
  --btn-text:     #080c12;
  --diff-ev-bg:   rgba(0,229,200,0.07);
  --diff-ice-bg:  rgba(255,160,50,0.07);
}

/* RESET */
*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Sora', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  transition: background 0.4s, color 0.4s;
  overflow-x: hidden;
}

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--accent); border-radius: 3px; }

/* NAVBAR */
#navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: var(--nav-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  transition: transform 0.35s cubic-bezier(0.4,0,0.2,1), background 0.4s;
}
#navbar.hidden { transform: translateY(-100%); }

.nav-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: 'Orbitron', monospace;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent);
  letter-spacing: 0.08em;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.nav-logo .logo-dot {
  width: 8px; height: 8px;
  background: var(--accent);
  border-radius: 50%;
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%,100% { transform: scale(1); opacity:1; }
  50% { transform: scale(1.5); opacity:0.6; }
}

nav ul {
  list-style: none;
  display: flex;
  gap: 0.2rem;
  align-items: center;
}
nav ul a {
  display: block;
  padding: 0.4rem 0.85rem;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
}
nav ul a:hover { color: var(--accent); background: var(--accent-glow); }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 4px;
}
.hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all 0.3s;
}

.theme-switch {
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  user-select: none;
  outline: none;
}
.theme-switch:focus-visible .switch-track {
  box-shadow: 0 0 0 2px var(--accent);
}

.switch-icon {
  flex-shrink: 0;
  transition: color 0.3s, opacity 0.3s;
}
.switch-sun {
  color: #f59e0b;
  opacity: 0.5;
}
.switch-moon {
  color: var(--accent);
  opacity: 0.5;
}
[data-theme="day"] .switch-sun { opacity: 1; }
[data-theme="night"] .switch-moon { opacity: 1; }

.switch-track {
  width: 40px;
  height: 22px;
  border-radius: 11px;
  background: var(--border);
  position: relative;
  transition: background 0.3s;
  flex-shrink: 0;
}
[data-theme="night"] .switch-track { background: var(--accent); }

.switch-thumb {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #ffffff;
  transition: transform 0.3s cubic-bezier(0.4,0,0.2,1);
  box-shadow: 0 1px 4px rgba(0,0,0,0.25);
}
.switch-thumb.active { transform: translateX(18px); }

.mobile-menu {
  display: none;
  flex-direction: column;
  background: var(--nav-bg);
  border-top: 1px solid var(--border);
  padding: 1rem 2rem;
  gap: 0.5rem;
}
.mobile-menu.open { display: flex; }
.mobile-menu a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 500;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
  transition: color 0.2s;
}
.mobile-menu a:hover { color: var(--accent); }

/* HERO */
#hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  padding-top: 64px;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-image: url('https://images.unsplash.com/photo-1593941707882-a5bba14938c7?w=1920&q=80');
  background-size: cover;
  background-position: center;
  filter: saturate(0.7);
  transition: filter 0.4s;
}
[data-theme="night"] .hero-bg { filter: saturate(0.4) brightness(0.6); }

.hero-overlay {
  position: absolute;
  inset: 0;
  background: var(--hero-overlay);
}

.hero-grid-lines {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 60px 60px;
  opacity: 0.3;
}

.hero-content {
  position: relative;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
  z-index: 2;
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.5rem;
  padding: 0.35rem 0.9rem;
  border: 1px solid var(--accent);
  border-radius: 50px;
  background: var(--accent-glow);
  margin-top: 1rem;
}

.hero-title {
  font-family: 'Orbitron', monospace;
  font-size: clamp(2.8rem, 7vw, 6.5rem);
  font-weight: 900;
  line-height: 1.02;
  color: var(--text);
  margin-bottom: 1.5rem;
}
.hero-title .hl {
  color: var(--accent);
  position: relative;
}
.hero-title .hl::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0; right: 0;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
}

.hero-sub {
  max-width: 560px;
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-bottom: 2.5rem;
  line-height: 1.8;
}

.hero-cta-group {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--accent);
  color: var(--btn-text);
  font-family: 'Sora', sans-serif;
  font-weight: 600;
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.85rem 2rem;
  border-radius: 8px;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 24px var(--accent-glow); }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: transparent;
  color: var(--text);
  font-family: 'Sora', sans-serif;
  font-weight: 600;
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.85rem 2rem;
  border-radius: 8px;
  text-decoration: none;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

.hero-stats {
  display: flex;
  gap: 3rem;
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
}
.stat-value {
  font-family: 'Orbitron', monospace;
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
}
.stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-top: 0.2rem;
}

/* SEÇÕES GERAIS */
.section {
  max-width: 1280px;
  margin: 0 auto;
  padding: 6rem 2rem;
}

.section.alt-bg {
  max-width: 100%;
  background: var(--bg-alt);
  transition: background 0.4s;
}
.section.alt-bg .section-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 6rem 2rem;
}

.section-header { margin-bottom: 3.5rem; }

.section-num {
  font-family: 'Orbitron', monospace;
  font-size: 5rem;
  font-weight: 900;
  color: var(--section-num);
  line-height: 1;
  margin-bottom: -1rem;
  user-select: none;
}

.section-label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.6rem;
}

.section-title {
  font-family: 'Orbitron', monospace;
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 700;
  color: var(--text);
  line-height: 1.15;
  margin-bottom: 1rem;
}

.section-desc {
  max-width: 640px;
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.8;
}

/* SOBRE */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.about-text p {
  font-size: 0.97rem;
  color: var(--text-muted);
  line-height: 1.85;
  margin-bottom: 1rem;
}

.about-img {
  border-radius: 16px;
  overflow: hidden;
  position: relative;
}
.about-img img {
  width: 100%;
  height: 380px;
  object-fit: cover;
  display: block;
  transition: transform 0.5s;
}
.about-img:hover img { transform: scale(1.04); }
.about-img::after {
  content: '';
  position: absolute;
  inset: 0;
  border: 2px solid var(--accent);
  border-radius: 16px;
  opacity: 0.4;
  pointer-events: none;
}

.keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1.5rem;
}
.kw-tag {
  background: var(--tag-bg);
  color: var(--tag-text);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.3rem 0.8rem;
  border-radius: 50px;
  letter-spacing: 0.04em;
}

/* FUNCIONAMENTO */
#funcionamento {
  background: var(--bg-alt);
  padding: 6rem 0;
  transition: background 0.4s;
}
.func-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
}

.func-parts-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-top: 2rem;
}

.part-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  transition: box-shadow 0.3s, border-color 0.3s;
}
.part-card:hover {
  box-shadow: var(--card-hover);
  border-color: var(--accent);
}
.part-card .part-icon {
  font-size: 2rem;
  margin-bottom: 0.8rem;
  display: block;
}
.part-card h4 {
  font-family: 'Orbitron', monospace;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 0.5rem;
  letter-spacing: 0.04em;
}
.part-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* COMPARATIVO */
.diff-wrapper {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  margin-top: 2rem;
}

.diff-col {
  border-radius: 16px;
  padding: 2rem;
  border: 1px solid var(--border);
}
.diff-col.ev { background: var(--diff-ev-bg); border-color: var(--accent); }
.diff-col.ice { background: var(--diff-ice-bg); border-color: #ff8c00; }

.diff-col h3 {
  font-family: 'Orbitron', monospace;
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1.2rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.diff-col.ev h3 { color: var(--accent); }
.diff-col.ice h3 { color: #ff8c00; }

.diff-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}
.diff-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.5;
}
.diff-list li .bullet {
  width: 18px; height: 18px;
  border-radius: 50%;
  flex-shrink: 0;
  margin-top: 1px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.65rem;
}
.diff-col.ev .bullet { background: var(--accent); color: #000; }
.diff-col.ice .bullet { background: #ff8c00; color: #fff; }

/* VANTAGENS */
.vantagens-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.van-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2rem;
  position: relative;
  overflow: hidden;
  transition: transform 0.3s, box-shadow 0.3s;
}
.van-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--accent);
  transform: scaleX(0);
  transition: transform 0.3s;
  transform-origin: left;
}
.van-card:hover { transform: translateY(-6px); box-shadow: var(--card-hover); }
.van-card:hover::before { transform: scaleX(1); }

.van-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  display: block;
}
.van-card h3 {
  font-family: 'Orbitron', monospace;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.7rem;
  letter-spacing: 0.03em;
}
.van-card p {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* DESAFIOS */
.desafios-layout {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 4rem;
  align-items: start;
}

.desafio-list {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

.desafio-item {
  display: flex;
  gap: 1rem;
  padding: 1.2rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  transition: border-color 0.2s;
  cursor: pointer;
}
.desafio-item:hover { border-color: var(--accent); }
.desafio-item.active { border-color: var(--accent); background: var(--accent-glow); }

.desafio-num {
  font-family: 'Orbitron', monospace;
  font-size: 1.5rem;
  font-weight: 900;
  color: var(--accent);
  opacity: 0.4;
  min-width: 2rem;
}
.desafio-item.active .desafio-num { opacity: 1; }

.desafio-text h4 {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text);
  margin-bottom: 0.3rem;
}
.desafio-text p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.desafio-visual img {
  width: 100%;
  height: 400px;
  object-fit: cover;
  border-radius: 16px;
  border: 1px solid var(--border);
  transition: opacity 0.25s;
}

/* SUSTENTABILIDADE */
.sustent-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.sustent-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  transition: box-shadow 0.3s;
}
.sustent-card:hover { box-shadow: var(--card-hover); }

.sustent-img {
  width: 100%;
  height: 220px;
  object-fit: cover;
  display: block;
  transition: transform 0.4s;
}
.sustent-card:hover .sustent-img { transform: scale(1.04); }

.sustent-body { padding: 1.5rem; }
.sustent-body h3 {
  font-family: 'Orbitron', monospace;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 0.6rem;
}
.sustent-body p {
  font-size: 0.87rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* PROJETO */
.site-tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}
.tab-btn {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-family: 'Sora', sans-serif;
  font-size: 0.8rem;
  font-weight: 500;
  padding: 0.5rem 1.2rem;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
}
.tab-btn.active, .tab-btn:hover {
  background: var(--accent);
  color: var(--btn-text);
  border-color: var(--accent);
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.site-pages-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}
.site-page-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}
.site-page-card img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  display: block;
}
.site-page-body { padding: 1rem 1.2rem; }
.site-page-body h4 {
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--text);
  margin-bottom: 0.3rem;
}
.site-page-body p {
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.tech-stack {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1rem;
}
.tech-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 1rem;
  font-size: 0.83rem;
  font-weight: 500;
  color: var(--text);
}
.tech-item .tech-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--accent);
}

/* CONCLUSÃO */
.conclusao-layout {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 4rem;
  align-items: center;
}

.conclusao-text p {
  font-size: 0.97rem;
  color: var(--text-muted);
  line-height: 1.85;
  margin-bottom: 1rem;
}

.conclusao-visual {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.metric-bar {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
.metric-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
}
.metric-label span:last-child { color: var(--accent); font-weight: 700; }
.bar-track {
  height: 8px;
  background: var(--border);
  border-radius: 4px;
  overflow: hidden;
}
.bar-fill {
  height: 100%;
  border-radius: 4px;
  background: var(--accent);
  width: 0;
  transition: width 1.5s cubic-bezier(0.4,0,0.2,1);
}

/* REFERÊNCIAS */
.ref-list {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  counter-reset: ref-counter;
}
.ref-item {
  counter-increment: ref-counter;
  display: flex;
  gap: 1rem;
  padding: 1rem 1.2rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.87rem;
  color: var(--text-muted);
  line-height: 1.6;
}
.ref-item::before {
  content: counter(ref-counter);
  font-family: 'Orbitron', monospace;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  min-width: 1.5rem;
  padding-top: 1px;
}
.ref-item a { color: var(--accent2); text-decoration: none; }
.ref-item a:hover { text-decoration: underline; }

/* FOOTER */
footer {
  background: var(--footer-bg);
  color: var(--footer-text);
  padding: 1.8rem 0 1.2rem;
  transition: background 0.4s;
}
.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem 1.2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  border-bottom: 1px solid rgba(255,255,255,0.06);
  margin-bottom: 1rem;
}

.footer-brand {
  font-family: 'Orbitron', monospace;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 0.3rem;
}
.footer-info p {
  font-size: 0.78rem;
  line-height: 1.6;
}
.footer-names {
  margin-top: 0.25rem;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 600;
}

.footer-github {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--footer-text);
  text-decoration: none;
  font-size: 0.82rem;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 8px;
  transition: color 0.2s, border-color 0.2s;
  white-space: nowrap;
}
.footer-github:hover { color: var(--accent); border-color: var(--accent); }

.footer-copy {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
  font-size: 0.72rem;
  text-align: center;
  opacity: 0.4;
}

/* BACK TO TOP */
#back-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px; height: 44px;
  background: var(--accent);
  color: #000;
  border: none;
  border-radius: 50%;
  font-size: 1.1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.3s, transform 0.3s;
  z-index: 500;
}
#back-top.visible { opacity: 1; transform: translateY(0); }

/* SCROLL REVEAL */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.7s cubic-bezier(0.4,0,0.2,1), transform 0.7s cubic-bezier(0.4,0,0.2,1);
}
.reveal.visible { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* RESPONSIVO */
@media (max-width: 1024px) {
  .about-grid, .diff-wrapper, .desafios-layout, .conclusao-layout {
    grid-template-columns: 1fr;
  }
  .func-parts-grid { grid-template-columns: repeat(2, 1fr); }
  .sustent-grid { grid-template-columns: 1fr; }
  .site-pages-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  nav ul { display: none; }
  .hamburger { display: flex; }
  #theme-toggle span:not(.t-icon) { display: none; }
  .hero-stats { gap: 1.5rem; }
  .func-parts-grid { grid-template-columns: 1fr; }
  .diff-wrapper { grid-template-columns: 1fr; }
  .hero-title { font-size: 2.5rem; }
  .section { padding: 4rem 1.2rem; }
  .section.alt-bg .section-inner { padding: 4rem 1.2rem; }
}