/* ===== Reset & Variables ===== */
:root {
  --c-primary: #2563eb;
  --c-primary-hover: #1d4ed8;
  --c-primary-light: #eff6ff;
  --c-text: #1e293b;
  --c-text-secondary: #64748b;
  --c-bg: #ffffff;
  --c-bg-alt: #f8fafc;
  --c-bg-dark: #0f172a;
  --c-border: #e2e8f0;
  --c-success: #16a34a;
  --radius: 8px;
  --radius-lg: 12px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
  color: var(--c-text);
  background: var(--c-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

.container { width: min(1200px, 100% - 32px); margin: 0 auto; }

/* ===== Navigation ===== */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--c-border);
}

.navbar.scrolled { box-shadow: 0 1px 8px rgba(0, 0, 0, 0.06); }

.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex; align-items: center; gap: 8px;
  font-size: 18px; font-weight: 700; color: var(--c-text);
}

.logo-icon {
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: var(--radius);
  background: var(--c-primary); color: #fff;
  font-size: 20px; font-weight: 800;
}

.nav-links { display: flex; gap: 8px; }
.nav-links a {
  padding: 8px 16px; border-radius: 6px;
  font-size: 15px; font-weight: 500; color: var(--c-text-secondary);
  transition: color 0.2s, background 0.2s;
}
.nav-links a:hover { color: var(--c-primary); background: var(--c-primary-light); }

.menu-toggle {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer; padding: 4px;
}
.menu-toggle span {
  display: block; width: 24px; height: 2px;
  background: var(--c-text); border-radius: 2px; transition: transform 0.3s;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 48px; padding: 0 28px; border-radius: var(--radius);
  font-size: 16px; font-weight: 600; cursor: pointer;
  transition: all 0.2s; border: 2px solid transparent;
}

.btn-primary {
  background: var(--c-primary); color: #fff;
}
.btn-primary:hover { background: var(--c-primary-hover); transform: translateY(-1px); box-shadow: 0 4px 16px rgba(37, 99, 235, 0.35); }

.btn-outline {
  background: transparent; color: var(--c-primary); border-color: var(--c-primary);
}
.btn-outline:hover { background: var(--c-primary-light); }

.btn-download {
  width: 100%; background: var(--c-primary); color: #fff; margin-top: auto;
}
.btn-download:hover { background: var(--c-primary-hover); }

/* ===== Hero ===== */
.hero {
  position: relative; overflow: hidden;
  padding: 100px 0 80px; text-align: center;
  background: linear-gradient(135deg, #f0f5ff 0%, #e8f0ff 50%, #f0f5ff 100%);
}

.hero h1 {
  font-size: clamp(32px, 5vw, 52px); font-weight: 800;
  line-height: 1.2; letter-spacing: -0.02em; margin-bottom: 20px;
}

.hero-desc {
  font-size: 18px; color: var(--c-text-secondary);
  max-width: 680px; margin: 0 auto 32px; line-height: 1.8;
}

.hero-actions { display: flex; justify-content: center; gap: 16px; flex-wrap: wrap; }

.hero-bg {
  position: absolute; top: -50%; left: 60%;
  width: 600px; height: 600px; border-radius: 50%;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.06) 0%, transparent 70%);
  pointer-events: none;
}

/* ===== Stats ===== */
.stats {
  padding: 40px 0; background: var(--c-bg);
  border-bottom: 1px solid var(--c-border);
}

.stats-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; text-align: center;
}

.stat-value {
  display: block; font-size: 28px; font-weight: 700; color: var(--c-primary);
  margin-bottom: 6px;
}

.stat-label {
  font-size: 14px; color: var(--c-text-secondary);
}

/* ===== Sections ===== */
.section { padding: 80px 0; }
.section-alt { background: var(--c-bg-alt); }

.section-header { text-align: center; margin-bottom: 48px; }
.section-header h2 {
  font-size: clamp(26px, 3.5vw, 36px); font-weight: 700;
  margin-bottom: 12px;
}
.section-header p {
  font-size: 17px; color: var(--c-text-secondary); max-width: 560px; margin: 0 auto;
}

/* ===== Feature Cards ===== */
.features-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}

.feature-card {
  background: var(--c-bg); border: 1px solid var(--c-border);
  border-radius: var(--radius-lg); padding: 28px;
  transition: transform 0.2s, box-shadow 0.2s;
}
.feature-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08); }

.feature-icon {
  display: flex; align-items: center; justify-content: center;
  width: 48px; height: 48px; border-radius: var(--radius);
  background: var(--c-primary-light); font-size: 22px; margin-bottom: 16px;
}

.feature-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.feature-card p { font-size: 15px; color: var(--c-text-secondary); line-height: 1.7; }

/* ===== Step Cards ===== */
.steps-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}

.step-card {
  background: var(--c-bg); border: 1px solid var(--c-border);
  border-radius: var(--radius-lg); padding: 32px 24px; position: relative;
}

.step-number {
  font-size: 48px; font-weight: 800; color: var(--c-primary-light);
  line-height: 1; margin-bottom: 12px;
}

.step-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 6px; }
.step-card > p { font-size: 14px; color: var(--c-text-secondary); margin-bottom: 16px; }

.code-block {
  background: #1e293b; color: #e2e8f0; border-radius: 6px;
  padding: 12px 16px; font-size: 13px; font-family: "Fira Code", "Cascadia Code", Consolas, monospace;
  overflow-x: auto; line-height: 1.6;
}

.code-comment { display: block; color: #94a3b8; margin-top: 4px; }

/* ===== Download Cards ===== */
.download-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}

.download-card {
  background: var(--c-bg); border: 1px solid var(--c-border);
  border-radius: var(--radius-lg); padding: 28px;
  display: flex; flex-direction: column;
  transition: transform 0.2s, box-shadow 0.2s;
}
.download-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08); }

.platform-badge {
  display: inline-flex; align-items: center;
  padding: 4px 14px; border-radius: 999px;
  font-size: 12px; font-weight: 700; margin-bottom: 14px;
}

.platform-badge.linux { background: #fef3c7; color: #d97706; }
.platform-badge.windows { background: #dbeafe; color: #2563eb; }
.platform-badge.web { background: #dcfce7; color: #16a34a; }

.download-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 6px; }
.download-card > p { font-size: 14px; color: var(--c-text-secondary); margin-bottom: 16px; }

.dl-info {
  padding: 12px; background: var(--c-bg-alt); border-radius: var(--radius);
  margin-bottom: 16px;
}

.dl-name { font-size: 13px; font-family: "Fira Code", Consolas, monospace; color: var(--c-text-secondary); word-break: break-all; }

/* ===== FAQ ===== */
.faq-list { max-width: 760px; margin: 0 auto; }

.faq-item { border-bottom: 1px solid var(--c-border); }

.faq-question {
  width: 100%; display: flex; align-items: center; justify-content: space-between;
  padding: 20px 4px; background: none; border: none;
  font-size: 16px; font-weight: 600; color: var(--c-text);
  cursor: pointer; text-align: left; line-height: 1.4;
}

.faq-icon {
  flex-shrink: 0; width: 24px; height: 24px; position: relative;
  margin-left: 16px;
}
.faq-icon::before, .faq-icon::after {
  content: ''; position: absolute; background: var(--c-primary); border-radius: 2px;
  transition: transform 0.3s;
}
.faq-icon::before { top: 11px; left: 4px; width: 16px; height: 2px; }
.faq-icon::after { top: 4px; left: 11px; width: 2px; height: 16px; }

.faq-question[aria-expanded="true"] .faq-icon::after { transform: rotate(90deg); }

.faq-answer {
  max-height: 0; overflow: hidden; transition: max-height 0.3s ease, padding 0.3s ease;
}
.faq-answer.open { max-height: 200px; padding-bottom: 20px; }
.faq-answer p { font-size: 15px; color: var(--c-text-secondary); line-height: 1.7; padding: 0 4px; }

/* ===== Footer ===== */
.footer {
  background: var(--c-bg-dark); color: #cbd5e1;
  padding: 56px 0 32px;
}

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

.footer-brand strong {
  display: block; font-size: 20px; color: #fff; margin-bottom: 8px;
}
.footer-brand p { font-size: 14px; line-height: 1.6; }

.footer-label {
  display: block; font-size: 13px; font-weight: 600; color: #fff;
  margin-bottom: 12px; text-transform: uppercase; letter-spacing: 0.05em;
}

.footer-links a {
  display: block; font-size: 14px; color: #94a3b8;
  padding: 4px 0; transition: color 0.2s;
}
.footer-links a:hover { color: #fff; }

.footer-bottom {
  border-top: 1px solid #334155;
  padding-top: 24px; text-align: center;
}
.footer-bottom p { font-size: 13px; color: #64748b; }

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex; flex-direction: column; position: absolute;
    top: 64px; left: 0; right: 0; background: var(--c-bg);
    border-bottom: 1px solid var(--c-border); padding: 12px 16px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
  }
  .menu-toggle { display: flex; }

  .hero { padding: 72px 0 56px; }
  .hero h1 { font-size: 30px; }

  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .features-grid, .steps-grid, .download-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
}

@media (max-width: 500px) {
  .stats-grid { grid-template-columns: 1fr; gap: 16px; }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { width: 100%; }
}