/* ═══════════════════════════════════════════════════════════════
   Heatline Design System
   ═══════════════════════════════════════════════════════════════ */

/* ── Variables ── */
:root {
  --bg: #1d2021;
  --bg-surface: #2b2f30;
  --bg-surface-hover: #323738;
  --bg-elevated: #323738;
  --bg-input: #1d2021;
  --border-default: #1d2021;
  --border-subtle: #34393b;
  --border-input: #43484a;

  --accent: #f97316;
  --accent-hover: #ea580c;
  --accent-subtle: rgba(249, 115, 22, 0.12);
  --accent-glow: rgba(249, 115, 22, 0.25);

  --secondary: #4db5da;
  --secondary-hover: #39809a;
  --secondary-muted: rgba(77, 181, 218, 0.15);

  --success: #34d399;
  --success-muted: rgba(52, 211, 153, 0.15);
  --danger: #e05a59;
  --danger-muted: rgba(224, 90, 89, 0.15);
  --warning: #fbbf24;

  --text: #fff;
  --text-secondary: #8e9191;
  --text-tertiary: #747778;

  --font-ui: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Consolas', 'Courier New', monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: 0.15s var(--ease);
  --transition-normal: 0.2s var(--ease);
  --transition-slow: 0.4s var(--ease);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-ui);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;

  /* Sticky-footer flex column: page is at least viewport-tall, <main> grows
     to fill any remaining vertical space so the footer settles at the bottom
     even when content is short. */
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main { flex: 1 0 auto; }
.footer { flex-shrink: 0; }

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { cursor: pointer; font-family: inherit; }
ul, ol { list-style: none; }

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border-input); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: #555a5c; }

/* ── Selection ── */
::selection { background: rgba(77, 181, 218, 0.3); color: var(--text); }

/* ── Focus ── */
:focus-visible {
  outline: 2px solid var(--secondary);
  outline-offset: 2px;
}

/* ── Hero Background Slideshow ── */
.hero__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: hidden;
}

.hero__bg-img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  transition: opacity 2s ease;
  will-change: opacity;
}

.hero__bg-img.is-active {
  opacity: 0.75;
}

.hero__bg-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    to bottom,
    rgba(29, 32, 33, 0.8) 0%,
    rgba(29, 32, 33, 0.85) 60%,
    rgba(29, 32, 33, 1) 100%
  );
  z-index: 1;
}


/* ── Container ── */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Typography ── */
h1, h2, h3, h4 { line-height: 1.15; font-weight: 700; }
h1 { font-size: clamp(2.2rem, 5vw, 3.5rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.6rem, 3vw, 2.25rem); letter-spacing: -0.01em; }
h3 { font-size: 1.15rem; font-weight: 600; }

.text-accent { color: var(--accent); }
.text-secondary-color { color: var(--secondary); }
.text-muted { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }
.mono { font-family: var(--font-mono); }

.section-label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 16px auto 0;
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: none;
  font-weight: 600;
  font-size: 14px;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  transition: all var(--transition-normal);
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 20px rgba(249, 115, 22, 0.3);
}

.btn-secondary {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-input);
}
.btn-secondary:hover {
  border-color: var(--secondary);
  color: var(--secondary);
}

.btn-lg {
  padding: 16px 40px;
  font-size: 15px;
}

.btn-sm {
  padding: 8px 18px;
  font-size: 12px;
}

.btn-block { width: 100%; }

/* ── Cards ── */
.card {
  background: var(--bg-surface);
  border: 2px solid var(--border-default);
  padding: 28px;
  transition: all var(--transition-normal);
  position: relative;
}

.card:hover {
  background: var(--bg-surface-hover);
  transform: translateY(-4px);
  box-shadow: 0 0 20px 1px var(--bg);
  z-index: 2;
}

.card-static {
  background: var(--bg-surface);
  border: 2px solid var(--border-default);
  padding: 28px;
}

.card-bordered-left {
  border-left: 3px solid var(--accent);
}

/* ── Badges / Tags ── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  font-size: 0.68rem;
  font-weight: 700;
  border-radius: 3px;
  letter-spacing: 0.5px;
}

.badge-accent {
  background: var(--accent-subtle);
  color: var(--accent);
}

.badge-secondary {
  background: var(--secondary-muted);
  color: var(--secondary);
}

.badge-success {
  background: var(--success-muted);
  color: var(--success);
}

.badge-danger {
  background: var(--danger-muted);
  color: var(--danger);
}

/* ── Navigation ── */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  height: 60px;
  background: var(--bg-surface);
  border-bottom: 2px solid var(--border-default);
  transition: box-shadow var(--transition-normal);
}

.nav--scrolled {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.nav__inner {
  display: flex;
  align-items: center;
  height: 100%;
  gap: 32px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 2.5px;
  flex-shrink: 0;
}

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

.nav__links {
  display: flex;
  align-items: center;
  gap: 28px;
  margin-left: auto;
}

.nav__links a {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.6px;
  text-transform: uppercase;
  color: var(--text-secondary);
  padding: 4px 0;
  position: relative;
  transition: color var(--transition-slow);
}

.nav__links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width var(--transition-slow);
}

.nav__links a:hover,
.nav__links a.active {
  color: var(--text);
}

.nav__links a:hover::after,
.nav__links a.active::after {
  width: 100%;
}

.nav__cta {
  margin-left: 12px;
  flex-shrink: 0;
}

.nav__burger {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  padding: 8px;
}

/* Mobile nav overlay */
.nav__mobile {
  display: block;
  position: fixed;
  inset: 0;
  z-index: 49;
  background: rgba(0, 0, 0, 0.7);
  opacity: 0;
  transition: opacity var(--transition-normal);
  pointer-events: none;
}

.nav__mobile.is-open {
  opacity: 1;
  pointer-events: auto;
}

.nav__mobile-panel {
  position: absolute;
  right: 0;
  top: 0;
  width: 280px;
  height: 100%;
  background: var(--bg-surface);
  border-left: 2px solid var(--border-default);
  padding: 80px 28px 28px;
  transform: translateX(100%);
  transition: transform var(--transition-normal);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.nav__mobile.is-open .nav__mobile-panel {
  transform: translateX(0);
}

.nav__mobile-panel a {
  display: block;
  padding: 14px 0;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-subtle);
  transition: color var(--transition-normal);
}

.nav__mobile-panel a:hover {
  color: var(--text);
}

.nav__mobile-panel a.btn-primary {
  color: #fff;
  border-bottom: none;
}

/* ── Section spacing ── */
.section {
  padding: 100px 0;
}

.section--tight {
  padding: 70px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

/* ── Grid ── */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2px;
}

/* ── Code blocks ── */
.code-block {
  background: var(--bg);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
  overflow-x: auto;
  color: var(--text-secondary);
}

.code-path {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--bg);
  border: 1px solid var(--border-subtle);
  border-radius: 4px;
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-secondary);
}

.copy-btn {
  background: none;
  border: 1px solid var(--border-input);
  color: var(--text-tertiary);
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.copy-btn:hover {
  border-color: var(--secondary);
  color: var(--secondary);
}

.copy-btn.copied {
  border-color: var(--success);
  color: var(--success);
}

/* ── FAQ Accordion ── */
.faq-item {
  background: var(--bg-surface);
  border: 2px solid var(--border-default);
  margin-bottom: 2px;
  transition: background var(--transition-normal);
}

.faq-item:hover {
  background: var(--bg-surface-hover);
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 20px 24px;
  background: none;
  border: none;
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  font-family: var(--font-ui);
}

.faq-chevron {
  width: 18px;
  height: 18px;
  color: var(--text-tertiary);
  transition: transform var(--transition-normal);
  flex-shrink: 0;
}

.faq-item.is-open .faq-chevron {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal);
}

.faq-answer-inner {
  padding: 0 24px 20px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-secondary);
}

/* ── Animations ── */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes pulseGlow {
  0%, 100% { box-shadow: 0 0 0 0 rgba(249, 115, 22, 0.4); }
  50% { box-shadow: 0 0 0 10px rgba(249, 115, 22, 0); }
}

@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.animate-on-scroll {
  opacity: 0;
  transform: translateY(20px);
}

.animate-on-scroll.is-visible {
  animation: fadeInUp 0.5s ease-out forwards;
}

.stagger-1 { animation-delay: 0.05s; }
.stagger-2 { animation-delay: 0.1s; }
.stagger-3 { animation-delay: 0.15s; }
.stagger-4 { animation-delay: 0.2s; }
.stagger-5 { animation-delay: 0.25s; }
.stagger-6 { animation-delay: 0.3s; }

.pulse-glow {
  animation: pulseGlow 2s ease-in-out infinite;
}

/* ── Footer ── */
.footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  padding: 48px 0 32px;
}

.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer__brand-desc {
  font-size: 13px;
  color: var(--text-secondary);
  margin-top: 12px;
  max-width: 300px;
  line-height: 1.7;
}

.footer__heading {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.6px;
  text-transform: uppercase;
  color: var(--text-tertiary);
  margin-bottom: 16px;
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer__links a {
  font-size: 13px;
  color: var(--text-secondary);
  transition: color var(--transition-normal);
}

.footer__links a:hover {
  color: var(--text);
}

.footer__bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 11px;
  color: var(--text-tertiary);
}

/* ── Responsive ── */
@media (max-width: 1024px) {
  .grid-2 { grid-template-columns: 1fr; }
  .footer__grid { grid-template-columns: 1fr 1fr; gap: 32px; }
}

@media (max-width: 768px) {
  .container { padding: 0 16px; }
  .section { padding: 60px 0; }
  .nav__inner { gap: 12px; }
  .nav__links { display: none; }
  .nav__user { display: none; }
  .nav__burger { display: block; }
  .grid-3 { grid-template-columns: 1fr; }
  .footer__grid { grid-template-columns: 1fr; gap: 28px; }
  .footer__bottom { flex-direction: column; gap: 8px; text-align: center; }
  .btn-lg { padding: 14px 32px; font-size: 14px; }
}