/* =====================
   Reset & Base
   ===================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, sans-serif;
}

html {
  scroll-behavior: smooth;
}

strong {
  color: #dfdfdf;
}

body {
  background: #0d1117;
  color: #e6edf3;
}

.site {
  background: #0d1117;
  color: #e6edf3;
  max-width: 100%;
  width: 100%;
}

/* =====================
   Navigation
   ===================== */
nav {
  background: #161b22;
  border-bottom: 1px solid #30363d;
  padding: 16px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-logo {
  display: flex;
  align-items: center;
  text-decoration: none;
  flex-shrink: 0;
}

.nav-logo img {
  height: 36px;
  width: auto;
  display: block;
}

.nav-links {
  display: flex;
  gap: 24px;
  align-items: center;
}

.nav-links a {
  color: #bdbfc1;
  font-size: 14px;
  text-decoration: none;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: #e6edf3;
}

.nav-btn {
  background: #238636;
  color: #fff;
  padding: 6px 16px;
  border-radius: 6px;
  font-size: 13px;
  text-decoration: none;
  font-weight: 500;
  transition: background 0.2s;
}

.nav-btn:hover {
  background: #2ea043;
}

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 22px;
  height: 16px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0;
}

.hamburger span {
  display: block;
  height: 2px;
  width: 100%;
  background: #8b949e;
  border-radius: 2px;
  transition: all 0.3s 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 nav overlay */
.mobile-nav {
  display: none;
  flex-direction: column;
  background: #161b22;
  border-bottom: 1px solid #30363d;
  padding: 16px 32px 24px;
  gap: 20px;
}

.mobile-nav.open {
  display: flex;
}

.mobile-nav a {
  color: #8b949e;
  font-size: 15px;
  text-decoration: none;
  transition: color 0.2s;
}

.mobile-nav a:hover {
  color: #e6edf3;
}

.mobile-nav .nav-btn {
  align-self: flex-start;
}

/* =====================
   Hero
   ===================== */
.hero {
  padding: 80px 32px;
  text-align: center;
  border-bottom: 1px solid #21262d;
}

.hero-sub {
  color: #e6edf3;
  font-size: 25px;
  margin-bottom: 16px;
  letter-spacing: 1px;
}

.hero h1 {
  font-size: 48px;
  font-weight: 600;
  color: #e6edf3;
  line-height: 1.2;
  margin-bottom: 16px;
}

.hero h1 span {
  color: #58a6ff;
}

.hero p {
  font-size: 17px;
  color: #bdbfc1;
  max-width: 560px;
  margin: 0 auto 32px;
  line-height: 1.7;
}

.hero-btns {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* =====================
   Buttons
   ===================== */
.btn-primary {
  background: #238636;
  color: #fff;
  padding: 12px 24px;
  border-radius: 6px;
  font-size: 15px;
  text-decoration: none;
  font-weight: 500;
  transition: background 0.2s;
}

.btn-primary:hover {
  background: #2ea043;
}

.btn-secondary {
  background: transparent;
  color: #58a6ff;
  padding: 12px 24px;
  border-radius: 6px;
  font-size: 15px;
  text-decoration: none;
  font-weight: 500;
  border: 1px solid #30363d;
  transition: border-color 0.2s, background 0.2s;
}

.btn-secondary:hover {
  border-color: #58a6ff;
  background: rgba(88, 166, 255, 0.05);
}

/* =====================
   Problem
   ===================== */
.problem {
  padding: 48px 32px;
  border-bottom: 1px solid #21262d;
  background: #161b22;
  text-align: center;
}

.problem h2 {
  font-size: 32px;
  font-weight: 600;
  color: #e6edf3;
}

.problem-headline {
  font-family: system-ui, -apple-system, sans-serif;
  font-weight: 600;
  font-size: 32px;
  color: #e6edf3;
  max-width: 600px;
  margin: 0 auto 20px;
  line-height: 1.2;
}

.problem p {
  font-size: 17px;
  color: #bdbfc1;
  max-width: 600px;
  margin: 0 auto 12px;
  line-height: 1.7;
  text-align: justify;
}

.problem strong {
  color: #e6edf3;
}

/* =====================
   Sections
   ===================== */
.section {
  padding: 64px 32px;
  border-bottom: 1px solid #21262d;
}

.section-tag {
  font-size: 12px;
  color: #58a6ff;
  font-weight: 500;
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.section h2 {
  font-size: 32px;
  font-weight: 600;
  color: #e6edf3;
  margin-bottom: 24px;
}


/* =====================
   Video Container
   ===================== */
.video-container {
  width: 80%;
  margin: 0 auto;
  margin-bottom: 32px;
}

/* =====================
   Steps
   ===================== */
.steps {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.step {
  background: #161b22;
  border: 1px solid #30363d;
  border-radius: 8px;
  padding: 24px;
  transition: border-color 0.2s;
}

.step:hover {
  border-color: #58a6ff40;
}

.step-num {
  width: 28px;
  height: 28px;
  background: #1f3f6d;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  color: #58a6ff;
  font-weight: 600;
  margin-bottom: 12px;
}

.step h3 {
  font-size: 15px;
  font-weight: 500;
  color: #e6edf3;
  margin-bottom: 8px;
}

.step p {
  font-size: 13px;
  color: #bdbfc1;
  line-height: 1.6;
}

.step-btns {
  display: flex;
  gap: 8px;
  margin-top: 12px;
  flex-wrap: wrap;
}

.step-btn-p {
  background: #238636;
  color: #fff;
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 12px;
  text-decoration: none;
  font-weight: 500;
  transition: background 0.2s;
}

.step-btn-p:hover {
  background: #2ea043;
}

.step-btn-s {
  background: transparent;
  color: #58a6ff;
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 12px;
  text-decoration: none;
  border: 1px solid #30363d;
  transition: border-color 0.2s;
}

.step-btn-s:hover {
  border-color: #58a6ff;
}

/* =====================
   Levels
   ===================== */
.levels {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 8px;
}

.level {
  background: #161b22;
  border: 1px solid #30363d;
  border-radius: 8px;
  padding: 16px;
  transition: border-color 0.2s;
}

.level:hover {
  border-color: #30363d80;
}

.level h3 {
  font-size: 14px;
  font-weight: 500;
  color: #e6edf3;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.level p {
  font-size: 12px;
  color: #bdbfc1;
}

/* =====================
   Open Source Box
   ===================== */
.opensource-box {
  background: #161b22;
  border: 1px solid #238636;
  border-radius: 8px;
  padding: 32px;
  margin-top: 8px;
}

.opensource-box h3 {
  font-size: 20px;
  font-weight: 500;
  color: #e6edf3;
  margin-bottom: 12px;
}

.opensource-box p {
  font-size: 14px;
  color: #bdbfc1;
  line-height: 1.7;
  margin-bottom: 20px;
}

/* =====================
   FAQ
   ===================== */
.faq {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 8px;
}

.faq-item {
  background: #161b22;
  border: 1px solid #30363d;
  border-radius: 8px;
  padding: 24px;
}

.faq-item h3 {
  font-size: 15px;
  font-weight: 500;
  color: #e6edf3;
  margin-bottom: 10px;
}

.faq-item p {
  font-size: 13px;
  color: #bdbfc1;
  line-height: 1.7;
}

/* =====================
   CTA
   ===================== */
.cta {
  text-align: center;
  padding: 64px 32px;
  background: #161b22;
  border-bottom: 1px solid #21262d;
}

.cta h2 {
  font-size: 32px;
  font-weight: 600;
  color: #e6edf3;
  margin-bottom: 12px;
}

.cta p {
  color: #bdbfc1;
  margin-bottom: 32px;
  font-size: 16px;
}

.dl-btns {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.dl-btn {
  background: #238636;
  color: #fff;
  padding: 12px 20px;
  border-radius: 6px;
  font-size: 14px;
  text-decoration: none;
  font-weight: 500;
  transition: background 0.2s;
}

.dl-btn:hover {
  background: #2ea043;
}

.dl-btn.sec {
  background: transparent;
  border: 1px solid #30363d;
  color: #58a6ff;
}

.dl-btn.sec:hover {
  border-color: #58a6ff;
  background: rgba(88, 166, 255, 0.05);
}

.cta-mention {
  font-size: 12px;
  color: #484f58;
}

/* =====================
   Footer
   ===================== */
footer {
  padding: 24px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #0d1117;
}

.footer-logo {
  color: #8b949e;
  font-size: 13px;
}

.footer-logo a {
  color: #58a6ff;
  text-decoration: none;
}

.footer-logo a:hover {
  text-decoration: underline;
}

/* =====================
   Responsive — Tablet (≤ 768px)
   ===================== */
@media (max-width: 768px) {
  nav {
    padding: 14px 20px;
  }

  .nav-links {
    display: none;
  }

  .nav-btn {
    display: none;
  }

  .hamburger {
    display: flex;
  }

  .mobile-nav {
    position: sticky;
    top: 53px;
    z-index: 99;
  }

  .hero {
    padding: 56px 20px;
  }

  .hero h1 {
    font-size: 36px;
  }

  .hero p {
    font-size: 15px;
  }

  .problem {
    padding: 36px 20px;
  }

  .problem p {
    font-size: 15px;
  }

  .section {
    padding: 48px 20px;
  }

  .section h2 {
    font-size: 26px;
  }

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

  .levels {
    grid-template-columns: repeat(2, 1fr);
  }

  .cta {
    padding: 48px 20px;
  }

  .cta h2 {
    font-size: 26px;
  }

  footer {
    padding: 20px;
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }
}

/* =====================
   Responsive — Mobile (≤ 480px)
   ===================== */
@media (max-width: 480px) {
  nav {
    padding: 12px 16px;
  }

  .nav-logo {
    font-size: 15px;
  }

  .mobile-nav {
    padding: 16px 16px 20px;
  }

  .hero {
    padding: 40px 16px;
  }

  .hero h1 {
    font-size: 28px;
  }

  .hero p {
    font-size: 14px;
  }

  .hero-btns {
    flex-direction: column;
    align-items: center;
  }

  .btn-primary,
  .btn-secondary {
    width: 100%;
    text-align: center;
    font-size: 14px;
  }

  .problem {
    padding: 28px 16px;
  }

  .problem p {
    font-size: 14px;
  }

  .section {
    padding: 36px 16px;
  }

  .section h2 {
    font-size: 22px;
  }

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

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

.opensource-box {
    padding: 24px 16px;
  }

  .cta {
    padding: 36px 16px;
  }

  .cta h2 {
    font-size: 22px;
  }

  .dl-btns {
    flex-direction: column;
    align-items: center;
  }

  .dl-btn {
    width: 100%;
    text-align: center;
  }

  footer {
    padding: 16px;
    font-size: 12px;
  }

  .faq-item {
    padding: 16px;
  }
}