/* ========================================
   ChirpLift — Brand Stylesheet
   Font: Inter (sans) + JetBrains Mono (mono)
   Primary: #1DA1F2 (X blue)
   Dark: #0f1419
   Accent: gradient blue->purple
   ======================================== */

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

:root {
  --color-bg: #0f1419;
  --color-bg-alt: #1a1f2e;
  --color-bg-card: #1e2538;
  --color-text: #e7e9ea;
  --color-text-muted: #8899a6;
  --color-text-dim: #536471;
  --color-primary: #279ED8;
  --color-primary-hover: #2290C5;
  --color-accent-1: #6366f1;
  --color-accent-2: #8b5cf6;
  --color-accent-3: #a855f7;
  --color-border: #2f3336;
  --color-success: #00ba7c;
  --color-error: #f4212e;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --max-width: 1200px;
  --header-height: 96px;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* --- TYPOGRAPHY --- */
.gradient-text {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent-2), var(--color-accent-3));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: 12px;
}
.section-label.centered { text-align: center; }

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 16px;
}
.section-title.centered { text-align: center; }

.section-subtitle {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  max-width: 640px;
  line-height: 1.6;
}
.section-subtitle.centered { margin: 0 auto 56px; text-align: center; }

/* --- BUTTONS --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  border: 2px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}
.btn--primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}
.btn--primary:hover {
  background: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(29, 161, 242, 0.25);
}
.btn--outline {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn--outline:hover {
  border-color: var(--color-text-muted);
  background: rgba(255,255,255,0.04);
  transform: translateY(-1px);
}
.btn--lg { padding: 16px 36px; font-size: 1.05rem; }
.btn--full { width: 100%; }
.btn--sm { padding: 8px 18px; font-size: 0.85rem; }

/* --- HEADER --- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(15, 20, 25, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
  transition: background 0.3s ease;
}
.header--scrolled { background: rgba(15, 20, 25, 0.96); }
.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.3rem;
  letter-spacing: -0.02em;
}
.logo__icon { display: block; flex-shrink: 0; border-radius: 50%; }
.logo__text { background: linear-gradient(135deg, var(--color-primary), var(--color-accent-2)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.nav__list { display: flex; gap: 32px; }
.nav__link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color 0.2s ease;
  position: relative;
}
.nav__link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width 0.3s ease;
}
.nav__link:hover { color: var(--color-text); }
.nav__link:hover::after { width: 100%; }
.header__cta { display: flex; }
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all 0.3s ease;
}

/* --- HERO --- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--header-height);
  overflow: hidden;
}
.hero__bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% 30%, rgba(29, 161, 242, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 20% 70%, rgba(99, 102, 241, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse 50% 40% at 80% 60%, rgba(139, 92, 246, 0.06) 0%, transparent 50%);
  pointer-events: none;
}
.hero__inner {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 40px 0 80px;
}
.hero__tagline {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: 20px;
}
.hero__title {
  font-size: clamp(3rem, 10vw, 7rem);
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 1;
  margin-bottom: 24px;
}
.hero__subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--color-text-muted);
  max-width: 680px;
  margin: 0 auto 40px;
  line-height: 1.7;
}
.hide-mobile { display: inline; }
.hero__ctas {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 64px;
}
.hero__stats {
  display: flex;
  gap: 48px;
  justify-content: center;
  flex-wrap: wrap;
}
.hero__stat { text-align: center; }
.hero__stat-num {
  display: inline;
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1;
}
.hero__stat-label {
  display: block;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-top: 6px;
}
.hero__scroll-indicator {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  color: var(--color-text-dim);
  animation: bounce 2s infinite;
}
@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* --- THESIS --- */
.thesis {
  padding: 100px 0;
  background: var(--color-bg-alt);
}
.thesis__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
.thesis__title {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 20px;
}
.thesis__text {
  color: var(--color-text-muted);
  margin-bottom: 16px;
  font-size: 1.05rem;
  line-height: 1.7;
}
.thesis__text strong { color: var(--color-text); }
.engagement-chart {
  display: flex;
  align-items: flex-end;
  gap: 24px;
  height: 240px;
  padding: 20px;
  background: var(--color-bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  justify-content: center;
}
.engagement-chart__bar {
  width: 100px;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  background: var(--color-border);
  position: relative;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding-bottom: 8px;
  transition: height 0.6s ease;
}
.engagement-chart__bar span {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-dim);
  writing-mode: vertical-lr;
  text-orientation: mixed;
}
.engagement-chart__bar--highlight {
  background: linear-gradient(180deg, var(--color-primary), var(--color-accent-2));
  box-shadow: 0 0 30px rgba(29, 161, 242, 0.2);
}
.engagement-chart__bar--highlight span { color: #fff; }
.thesis__chart-caption {
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-text-dim);
  margin-top: 12px;
  font-family: var(--font-mono);
}

/* --- HOW IT WORKS / STEPS --- */
.how-it-works {
  padding: 100px 0;
}
.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-top: 16px;
}
.step {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.step:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.3);
}
.step__num {
  font-family: var(--font-mono);
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 16px;
}
.step__title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 12px;
}
.step__desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.65;
}

/* --- NETWORK (VAGUE / QUALITIES) --- */
.network {
  padding: 100px 0;
  background: var(--color-bg-alt);
}
.network__qualities {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 48px;
}
.network__quality {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  text-align: center;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.network__quality:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.3);
}
.network__quality-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(29, 161, 242, 0.1);
  border-radius: 12px;
  color: var(--color-primary);
}
.network__quality h4 {
  font-weight: 700;
  font-size: 1.05rem;
  margin-bottom: 10px;
}
.network__quality p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.65;
}
.network__cta {
  text-align: center;
}
.network__cta-text {
  color: var(--color-text-muted);
  margin-bottom: 20px;
  font-size: 1rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* --- SERVICES --- */
.services {
  padding: 100px 0;
}
.services__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.service-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  position: relative;
  display: flex;
  flex-direction: column;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.service-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.3);
}
.service-card--featured {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 1px rgba(29, 161, 242, 0.3), 0 8px 32px rgba(29, 161, 242, 0.1);
}
.service-card--featured:hover {
  box-shadow: 0 0 0 1px rgba(29, 161, 242, 0.5), 0 12px 48px rgba(29, 161, 242, 0.2);
}
.service-card__badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-primary);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 16px;
  border-radius: 100px;
  letter-spacing: 0.03em;
}
.service-card__icon {
  color: var(--color-primary);
  margin-bottom: 20px;
}
.service-card__title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
}
.service-card__desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  margin-bottom: 20px;
  flex: 1;
}
.service-card__features {
  margin-bottom: 24px;
}
.service-card__features li {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  padding: 6px 0;
  padding-left: 20px;
  position: relative;
}
.service-card__features li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 13px;
  width: 10px;
  height: 2px;
  background: var(--color-primary);
  border-radius: 2px;
}
.service-card__btn {
  margin-top: auto;
}

/* --- TESTIMONIALS --- */
.testimonials {
  padding: 100px 0;
  background: var(--color-bg-alt);
}
.testimonials__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.testimonial-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
}
.testimonial-card__stars {
  color: #f59e0b;
  font-size: 1rem;
  margin-bottom: 16px;
  letter-spacing: 2px;
}
.testimonial-card__quote {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  flex: 1;
  margin-bottom: 20px;
  font-style: italic;
}
.testimonial-card__author {
  display: flex;
  align-items: center;
  gap: 12px;
}
.testimonial-card__avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  color: #fff;
  flex-shrink: 0;
}
.testimonial-card__name {
  font-weight: 600;
  font-size: 0.9rem;
}
.testimonial-card__role {
  font-size: 0.8rem;
  color: var(--color-text-dim);
}

/* --- FAQ --- */
.faq {
  padding: 100px 0;
}
.faq__list {
  max-width: 720px;
  margin: 16px auto 0;
}
.faq__item {
  border-bottom: 1px solid var(--color-border);
}
.faq__question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 20px 0;
  background: none;
  border: none;
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  gap: 16px;
  transition: color 0.2s ease;
}
.faq__question:hover { color: var(--color-primary); }
.faq__question svg {
  flex-shrink: 0;
  transition: transform 0.3s ease;
}
.faq__question[aria-expanded="true"] svg { transform: rotate(180deg); }
.faq__answer {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.35s ease, padding 0.35s ease;
}
.faq__answer p {
  padding: 0 0 20px;
  color: var(--color-text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}
.faq__question[aria-expanded="true"] + .faq__answer { max-height: 400px; }

/* --- CONTACT --- */
.contact {
  padding: 100px 0;
  background: var(--color-bg-alt);
}
.contact__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}
.contact__title {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 16px;
}
.contact__text {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 32px;
}
.contact__details li {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin-bottom: 16px;
}
.contact__details li svg { color: var(--color-primary); flex-shrink: 0; }

.contact__form {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 36px;
}
.form-group {
  margin-bottom: 20px;
}
.form-group label {
  display: block;
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--color-text);
}
.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  transition: border-color 0.2s ease;
  outline: none;
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(29, 161, 242, 0.1);
}
.form-group input::placeholder,
.form-group textarea::placeholder { color: var(--color-text-dim); }
.form-group select { cursor: pointer; }
.form-group select option { background: var(--color-bg); }
.form-group textarea { resize: vertical; min-height: 100px; }
.form__footnote {
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-text-dim);
  margin-top: 16px;
}

/* --- FOOTER --- */
.footer {
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
  padding: 64px 0 0;
}
.footer__inner {
  display: grid;
  grid-template-columns: 1.5fr 2fr;
  gap: 64px;
  padding-bottom: 48px;
}
.footer__tagline {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-top: 12px;
  max-width: 320px;
  line-height: 1.6;
}
.footer__links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}
.footer__col h5 {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-dim);
  margin-bottom: 16px;
}
.footer__col li { margin-bottom: 10px; }
.footer__col a {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  transition: color 0.2s ease;
}
.footer__col a:hover { color: var(--color-primary); }
.footer__bottom {
  border-top: 1px solid var(--color-border);
  padding: 24px 0;
}
.footer__bottom p {
  font-size: 0.8rem;
  color: var(--color-text-dim);
}

/* --- RESPONSIVE --- */
@media (max-width: 1024px) {
  .steps { grid-template-columns: repeat(2, 1fr); }
  .network__qualities { grid-template-columns: repeat(2, 1fr); }
  .services__grid { grid-template-columns: 1fr; max-width: 480px; margin: 0 auto; }
  .testimonials__grid { grid-template-columns: 1fr; max-width: 480px; margin: 0 auto; }
}

@media (max-width: 768px) {
  :root { --header-height: 64px; }
  .container { padding: 0 16px; }

  .nav { display: none; }
  .nav--open { display: block; position: fixed; top: var(--header-height); left: 0; right: 0; background: rgba(15,20,25,0.98); border-bottom: 1px solid var(--color-border); padding: 24px; }
  .nav--open .nav__list { flex-direction: column; gap: 20px; }
  .header__cta { display: none; }
  .hamburger { display: flex; }

  .hero__title { font-size: clamp(2.5rem, 12vw, 4rem); }
  .hide-mobile { display: none; }
  .hero__stats { gap: 24px; }
  .hero__stat-num { font-size: 1.6rem; }

  .thesis__grid { grid-template-columns: 1fr; gap: 40px; }
  .engagement-chart { height: 180px; }
  .engagement-chart__bar { width: 72px; }

  .steps { grid-template-columns: 1fr; }

  .network__qualities { grid-template-columns: 1fr; max-width: 360px; margin: 0 auto 48px; }

  .contact__grid { grid-template-columns: 1fr; gap: 40px; }

  .footer__inner { grid-template-columns: 1fr; gap: 40px; }
  .footer__links { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 480px) {
  .hero__ctas { flex-direction: column; align-items: center; }
  .hero__ctas .btn { width: 100%; max-width: 320px; }
  .footer__links { grid-template-columns: 1fr; }
}