/* ==========================================================================
   ADATRO Computer Basics — style.css
   Mobile-first responsive stylesheet. No frameworks, hand-written.
   Sections: 1. Tokens  2. Reset  3. Layout utilities  4. Navbar
   5. Hero  6. About  7. Curriculum  8. Benefits  9. Why/Instructor
   10. Testimonials  11. FAQ  12. Join  13. Contact  14. Footer
   15. Floating buttons  16. Animations  17. Responsive breakpoints
   ========================================================================== */

/* ---------- 1. Design tokens ---------- */
:root{
  --navy-deep:   #0B1026;
  --navy-mid:    #131A3A;
  --navy-card:   #161E44;
  --navy-border: #262F58;
  --green:       #A3E635;
  --green-dim:   #8BC926;
  --blue:        #2563EB;
  --blue-dim:    #1D4ED8;
  --white:       #FFFFFF;
  --ink-soft:    #C4C9DC;
  --ink-mute:    #8B92B0;

  --font-display: 'Sora', 'Segoe UI', sans-serif;
  --font-body: 'Inter', 'Segoe UI', sans-serif;

  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;

  --shadow-soft: 0 10px 30px rgba(5, 8, 24, 0.35);
  --shadow-card: 0 4px 24px rgba(5, 8, 24, 0.28);
  --shadow-glow-green: 0 0 40px rgba(163, 230, 53, 0.25);
  --shadow-glow-blue: 0 0 40px rgba(37, 99, 235, 0.3);

  --ease: cubic-bezier(.4,0,.2,1);
}

/* ---------- 2. Reset ---------- */
*, *::before, *::after{ box-sizing: border-box; margin: 0; padding: 0; }
html{ scroll-behavior: smooth; }
body{
  background: var(--navy-deep);
  color: var(--white);
  font-family: var(--font-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img, svg{ display: block; max-width: 100%; }
a{ color: inherit; text-decoration: none; }
ul{ list-style: none; }
button{ font: inherit; background: none; border: none; cursor: pointer; color: inherit; }
h1,h2,h3,h4{ font-family: var(--font-display); font-weight: 700; line-height: 1.15; }
::selection{ background: var(--green); color: var(--navy-deep); }

@media (prefers-reduced-motion: reduce){
  *{ animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; scroll-behavior: auto !important; }
}

/* focus visibility */
a:focus-visible, button:focus-visible{
  outline: 2px solid var(--green);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 3. Layout utilities ---------- */
.container{
  width: 100%;
  max-width: 1200px;
  margin-inline: auto;
  padding-inline: 20px;
}
section{ padding-block: 72px; position: relative; }

.eyebrow{
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--green);
  margin-bottom: 14px;
}
.eyebrow--light{ color: var(--navy-deep); }

.section-head{ max-width: 640px; margin-bottom: 44px; }
.section-head h2{ font-size: clamp(1.6rem, 4vw, 2.4rem); margin-bottom: 14px; }
.section-lead{ color: var(--ink-soft); font-size: 1rem; }

.text-gradient{
  background: linear-gradient(90deg, var(--green), var(--blue));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* Buttons */
.btn{
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 26px;
  border-radius: 999px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  white-space: nowrap;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), background 0.25s var(--ease);
}
.btn:hover{ transform: translateY(-2px); }
.btn:active{ transform: translateY(0); }

.btn--primary{
  background: var(--blue);
  color: var(--white);
  box-shadow: var(--shadow-glow-blue);
}
.btn--primary:hover{ background: var(--blue-dim); }

.btn--outline{
  background: transparent;
  color: var(--green);
  border: 1.5px solid var(--green);
}
.btn--outline:hover{ background: rgba(163,230,53,0.1); box-shadow: var(--shadow-glow-green); }

.btn--sm{ padding: 10px 20px; font-size: 0.85rem; }

.btn--community{
  background: var(--navy-card);
  border: 1px solid var(--navy-border);
  color: var(--white);
  font-size: 0.9rem;
  padding: 13px 22px;
}
.btn--community:hover{ border-color: var(--green); color: var(--green); }

/* ---------- 4. Navbar ---------- */
.navbar{
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 200;
  padding-block: 18px;
  transition: background 0.3s var(--ease), padding 0.3s var(--ease), box-shadow 0.3s var(--ease);
}
.navbar.scrolled{
  background: rgba(11, 16, 38, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  padding-block: 12px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
  border-bottom: 1px solid var(--navy-border);
}
.navbar__inner{ display: flex; align-items: center; justify-content: space-between; }

.logo{ display: flex; align-items: center; gap: 10px; }
.logo__text{
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.3rem;
  letter-spacing: 0.02em;
}

.nav-links{ display: none; align-items: center; gap: 30px; }
.nav-link{
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--ink-soft);
  position: relative;
  transition: color 0.2s;
}
.nav-link::after{
  content: '';
  position: absolute;
  left: 0; bottom: -6px;
  width: 0; height: 2px;
  background: var(--green);
  transition: width 0.25s var(--ease);
}
.nav-link:hover{ color: var(--white); }
.nav-link:hover::after{ width: 100%; }

.navbar__actions{ display: flex; align-items: center; gap: 14px; }
.navbar__actions .btn--primary{ display: none; }

.hamburger{
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px; height: 40px;
  padding: 10px;
}
.hamburger span{
  display: block;
  height: 2px;
  width: 100%;
  background: var(--white);
  border-radius: 2px;
  transition: transform 0.3s var(--ease), opacity 0.3s var(--ease);
}
.hamburger.open span:nth-child(1){ transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2){ opacity: 0; }
.hamburger.open span:nth-child(3){ transform: translateY(-7px) rotate(-45deg); }

.mobile-menu{
  position: fixed;
  top: 0; right: -100%;
  width: min(78vw, 340px);
  height: 100vh;
  background: var(--navy-mid);
  border-left: 1px solid var(--navy-border);
  z-index: 199;
  display: flex;
  flex-direction: column;
  padding: 100px 32px 40px;
  gap: 22px;
  transition: right 0.4s var(--ease);
  box-shadow: -20px 0 50px rgba(0,0,0,0.4);
}
.mobile-menu.open{ right: 0; }
.mobile-link{ font-size: 1.05rem; font-weight: 500; color: var(--ink-soft); }
.mobile-link:hover{ color: var(--green); }
.mobile-join{ margin-top: 12px; width: fit-content; }

/* ---------- 5. Hero ---------- */
.hero{
  padding-top: 140px;
  padding-bottom: 60px;
  position: relative;
  overflow: hidden;
}
.hero__glow{
  position: absolute;
  top: -180px; left: 50%;
  transform: translateX(-50%);
  width: 900px; height: 500px;
  background: radial-gradient(circle, rgba(37,99,235,0.35), transparent 65%);
  z-index: 0;
  pointer-events: none;
}
.hero__inner{
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: 48px;
}
.hero__title{
  font-size: clamp(2.1rem, 7vw, 3.4rem);
  margin-bottom: 20px;
  letter-spacing: -0.01em;
}
.hero__subtitle{
  color: var(--ink-soft);
  font-size: 1.08rem;
  max-width: 480px;
  margin-bottom: 32px;
}
.hero__actions{ display: flex; flex-wrap: wrap; gap: 16px; margin-bottom: 40px; }
.hero__stats{ display: flex; gap: 32px; flex-wrap: wrap; }
.hero__stats div{ display: flex; flex-direction: column; }
.hero__stats strong{ font-family: var(--font-display); font-size: 1.4rem; color: var(--green); }
.hero__stats span{ font-size: 0.82rem; color: var(--ink-mute); }

.hero__art{ display: flex; justify-content: center; }
.hero-illustration{ width: 100%; max-width: 460px; }

.pulse-key{ animation: pulseKey 2.4s ease-in-out infinite; }
@keyframes pulseKey{ 0%,100%{ opacity: 1; } 50%{ opacity: 0.55; } }
.spin-slow{ transform-origin: center; animation: spin 6s linear infinite; }
@keyframes spin{ to{ transform: rotate(360deg); } }

/* ---------- 6. About ---------- */
.topic-grid{
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}
.topic-chip{
  background: var(--navy-card);
  border: 1px solid var(--navy-border);
  border-radius: var(--radius-sm);
  padding: 16px 18px;
  font-weight: 500;
  font-size: 0.92rem;
  transition: transform 0.25s var(--ease), border-color 0.25s var(--ease), background 0.25s var(--ease);
}
.topic-chip:hover{
  border-color: var(--green);
  background: rgba(163,230,53,0.06);
  transform: translateY(-3px);
}

/* ---------- 7. Curriculum ---------- */
.module-grid{
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}
.module-card{
  background: linear-gradient(160deg, var(--navy-card), var(--navy-mid));
  border: 1px solid var(--navy-border);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  box-shadow: var(--shadow-card);
  transition: transform 0.3s var(--ease), border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
  position: relative;
  overflow: hidden;
}
.module-card::before{
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 100%;
  background: linear-gradient(180deg, var(--green), var(--blue));
  opacity: 0;
  transition: opacity 0.3s var(--ease);
}
.module-card:hover{
  transform: translateY(-6px);
  border-color: var(--blue);
  box-shadow: var(--shadow-soft);
}
.module-card:hover::before{ opacity: 1; }
.module-number{
  font-family: var(--font-display);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--blue);
  background: rgba(37,99,235,0.12);
  border-radius: 999px;
  padding: 5px 12px;
  display: inline-block;
  margin-bottom: 16px;
}
.module-card h3{ font-size: 1.1rem; margin-bottom: 8px; }
.module-card p{ color: var(--ink-mute); font-size: 0.9rem; }

/* ---------- 8. Benefits ---------- */
.benefit-grid{
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}
.benefit-card{
  background: var(--navy-card);
  border: 1px solid var(--navy-border);
  border-radius: var(--radius-md);
  padding: 30px 24px;
  transition: transform 0.3s var(--ease), border-color 0.3s var(--ease);
}
.benefit-card:hover{ transform: translateY(-5px); border-color: var(--green); }
.benefit-icon{
  width: 52px; height: 52px;
  border-radius: 14px;
  background: rgba(163,230,53,0.1);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 18px;
}
.benefit-card h3{ font-size: 1.08rem; margin-bottom: 8px; }
.benefit-card p{ color: var(--ink-mute); font-size: 0.9rem; }

/* ---------- 9. Why / Instructor ---------- */
.why__inner{
  display: flex;
  flex-direction: column;
  gap: 48px;
}
.why-list{ display: flex; flex-direction: column; gap: 20px; margin-top: 30px; }
.why-list li{ display: flex; gap: 16px; align-items: flex-start; }
.why-check{
  flex-shrink: 0;
  width: 30px; height: 30px;
  border-radius: 50%;
  background: rgba(37,99,235,0.15);
  color: var(--blue);
  display: flex; align-items: center; justify-content: center;
  font-weight: 700;
}
.why-list strong{ font-family: var(--font-display); display: block; margin-bottom: 4px; }
.why-list p{ color: var(--ink-mute); font-size: 0.9rem; }

.why__panel{ display: flex; justify-content: center; }
.instructor-card{
  background: linear-gradient(160deg, var(--navy-card), var(--navy-mid));
  border: 1px solid var(--navy-border);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  text-align: center;
  max-width: 340px;
  width: 100%;
  box-shadow: var(--shadow-soft);
}
.instructor-avatar{
  width: 76px; height: 76px;
  border-radius: 50%;
  margin: 0 auto 20px;
  background: linear-gradient(135deg, var(--green), var(--blue));
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.5rem;
  color: var(--navy-deep);
}
.instructor-card h3{ font-size: 1.15rem; margin-bottom: 8px; }
.instructor-card p{ color: var(--ink-mute); font-size: 0.9rem; margin-bottom: 16px; }
.instructor-rating{ color: var(--green); font-size: 0.95rem; }
.instructor-rating span{ display: block; color: var(--ink-mute); font-size: 0.78rem; margin-top: 4px; }

/* ---------- 10. Testimonials ---------- */
.testimonial-grid{
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}
.testimonial-card{
  background: var(--navy-card);
  border: 1px solid var(--navy-border);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  transition: transform 0.3s var(--ease);
}
.testimonial-card:hover{ transform: translateY(-5px); }
.stars{ color: var(--green); letter-spacing: 2px; margin-bottom: 14px; font-size: 0.9rem; }
.testimonial-card p{ color: var(--ink-soft); font-size: 0.95rem; margin-bottom: 22px; font-style: italic; }
.testimonial-person{ display: flex; align-items: center; gap: 12px; }
.avatar{
  width: 42px; height: 42px;
  border-radius: 50%;
  background: rgba(37,99,235,0.18);
  color: var(--blue);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.85rem;
}
.testimonial-person strong{ display: block; font-size: 0.92rem; }
.testimonial-person span{ font-size: 0.8rem; color: var(--ink-mute); }

/* ---------- 11. FAQ ---------- */
.accordion{ display: flex; flex-direction: column; gap: 14px; }
.accordion-item{
  background: var(--navy-card);
  border: 1px solid var(--navy-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.25s var(--ease);
}
.accordion-item.active{ border-color: var(--blue); }
.accordion-header{
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 22px;
  text-align: left;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.98rem;
}
.accordion-icon{
  flex-shrink: 0;
  width: 28px; height: 28px;
  border-radius: 50%;
  background: rgba(163,230,53,0.12);
  color: var(--green);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem;
  transition: transform 0.3s var(--ease);
}
.accordion-item.active .accordion-icon{ transform: rotate(45deg); }
.accordion-panel{
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s var(--ease), padding 0.35s var(--ease);
  padding: 0 22px;
}
.accordion-item.active .accordion-panel{ padding: 0 22px 22px; }
.accordion-panel p{ color: var(--ink-mute); font-size: 0.92rem; }

/* ---------- 12. Join community ---------- */
.join{
  background: linear-gradient(135deg, var(--green), #7cc41f 55%, var(--blue));
  color: var(--navy-deep);
  overflow: hidden;
  position: relative;
}
.join__glow{
  position: absolute; inset: 0;
  background: radial-gradient(circle at 80% 20%, rgba(255,255,255,0.25), transparent 55%);
  pointer-events: none;
}
.join__inner{ position: relative; z-index: 1; text-align: center; max-width: 680px; }
.join h2{ font-size: clamp(1.6rem, 4.5vw, 2.3rem); margin-bottom: 14px; color: var(--navy-deep); }
.join p{ color: rgba(11,16,38,0.75); margin-bottom: 32px; }
.join__buttons{ display: flex; flex-wrap: wrap; gap: 14px; justify-content: center; }
.btn--community{ backdrop-filter: blur(4px); }
.join .btn--community{
  background: rgba(11,16,38,0.9);
  border: 1px solid rgba(11,16,38,0.9);
  color: var(--white);
}
.join .btn--community:hover{ background: var(--navy-deep); color: var(--green); }

/* ---------- 13. Contact ---------- */
.contact-grid{
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
.contact-card{
  background: var(--navy-card);
  border: 1px solid var(--navy-border);
  border-radius: var(--radius-md);
  padding: 24px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  transition: transform 0.25s var(--ease), border-color 0.25s var(--ease);
}
.contact-card:hover{ transform: translateY(-4px); border-color: var(--blue); }
.contact-icon{ font-size: 1.4rem; margin-bottom: 6px; color: var(--green); }
.contact-card strong{ font-family: var(--font-display); font-size: 0.98rem; }
.contact-card span{ color: var(--ink-mute); font-size: 0.85rem; }

/* ---------- 14. Footer ---------- */
.footer{
  background: var(--navy-mid);
  border-top: 1px solid var(--navy-border);
  padding-top: 60px;
}
.footer__inner{
  display: flex;
  flex-direction: column;
  gap: 40px;
  padding-bottom: 40px;
}
.footer__brand p{ color: var(--ink-mute); font-size: 0.9rem; margin: 14px 0 18px; }
.footer__socials{ display: flex; gap: 10px; }
.footer__socials a{
  width: 38px; height: 38px;
  border-radius: 50%;
  border: 1px solid var(--navy-border);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.85rem;
  transition: border-color 0.25s var(--ease), color 0.25s var(--ease);
}
.footer__socials a:hover{ border-color: var(--green); color: var(--green); }

.footer__col h4{ font-size: 0.95rem; margin-bottom: 16px; color: var(--white); }
.footer__col a{
  display: block;
  color: var(--ink-mute);
  font-size: 0.9rem;
  padding: 6px 0;
  transition: color 0.2s;
}
.footer__col a:hover{ color: var(--green); }

.footer__bottom{
  border-top: 1px solid var(--navy-border);
  padding: 22px 20px;
  text-align: center;
}
.footer__bottom p{ color: var(--ink-mute); font-size: 0.82rem; }

/* ---------- 15. Floating buttons ---------- */
.floating-buttons{
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 150;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.fab{
  width: 50px; height: 50px;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-soft);
  transition: transform 0.25s var(--ease), opacity 0.25s var(--ease);
}
.fab:hover{ transform: translateY(-3px) scale(1.05); }
.fab--whatsapp{ background: #25D366; color: #fff; }
.fab--telegram{ background: var(--blue); color: #fff; }
.fab--top{
  background: var(--navy-card);
  border: 1px solid var(--navy-border);
  color: var(--green);
  opacity: 0;
  pointer-events: none;
  transform: translateY(10px);
}
.fab--top.visible{ opacity: 1; pointer-events: auto; transform: translateY(0); }

/* ---------- 16. Scroll reveal animations ---------- */
.reveal{
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.reveal.in-view{ opacity: 1; transform: translateY(0); }

.hero__copy.reveal{ transition-delay: 0.05s; }
.hero__art.reveal{ transition-delay: 0.2s; }

/* ---------- 17. Responsive breakpoints ---------- */

/* Tablet ≥ 640px */
@media (min-width: 640px){
  .topic-grid{ grid-template-columns: repeat(3, 1fr); }
  .module-grid{ grid-template-columns: repeat(2, 1fr); }
  .benefit-grid{ grid-template-columns: repeat(2, 1fr); }
  .testimonial-grid{ grid-template-columns: repeat(2, 1fr); }
  .contact-grid{ grid-template-columns: repeat(3, 1fr); }
  .footer__inner{ flex-direction: row; flex-wrap: wrap; justify-content: space-between; }
  .footer__brand{ max-width: 260px; }
}

/* Desktop ≥ 900px */
@media (min-width: 900px){
  section{ padding-block: 100px; }
  .nav-links{ display: flex; }
  .navbar__actions .btn--primary{ display: inline-flex; }
  .hamburger{ display: none; }

  .hero{ padding-top: 170px; }
  .hero__inner{ flex-direction: row; align-items: center; justify-content: space-between; }
  .hero__copy{ flex: 1; max-width: 540px; }
  .hero__art{ flex: 1; }

  .topic-grid{ grid-template-columns: repeat(4, 1fr); }
  .module-grid{ grid-template-columns: repeat(3, 1fr); }
  .benefit-grid{ grid-template-columns: repeat(3, 1fr); }
  .testimonial-grid{ grid-template-columns: repeat(3, 1fr); }
  .contact-grid{ grid-template-columns: repeat(6, 1fr); }

  .why__inner{ flex-direction: row; align-items: center; gap: 70px; }
  .why__copy{ flex: 1.1; }
  .why__panel{ flex: 0.9; }
}

/* Large desktop ≥ 1200px */
@media (min-width: 1200px){
  .module-grid{ grid-template-columns: repeat(4, 1fr); }
}