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

:root {
  --navy:        #0f172a;
  --navy-light:  #1e293b;
  --accent:      #1d4ed8;
  --accent-hover:#1e40af;
  --accent-light:#eff6ff;
  --text:        #1e293b;
  --muted:       #64748b;
  --border:      #e2e8f0;
  --surface:     #ffffff;
  --bg:          #f8fafc;
  --code-bg:     #0f172a;
  --code-text:   #e2e8f0;
  --radius:      10px;
  --shadow:      0 1px 3px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.06);
}

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 1rem;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── Layout ── */
.inner {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* ── Navbar ── */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-weight: 800;
  font-size: 1.05rem;
  color: var(--navy);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--muted);
  transition: color 0.15s;
}

.nav-links a:hover { color: var(--accent); text-decoration: none; }

.nav-github {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--navy);
  color: #fff !important;
  padding: 0.35rem 0.85rem;
  border-radius: 6px;
  font-size: 0.82rem !important;
  font-weight: 600 !important;
  transition: background 0.15s;
}

.nav-github:hover { background: var(--navy-light); text-decoration: none; }

/* ── Hero ── */
.hero {
  background: linear-gradient(135deg, var(--navy) 0%, #1e3a8a 100%);
  color: #fff;
  padding: 5rem 2rem;
}

.hero-inner {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 3rem;
}

.hero-logo {
  width: 320px;
  height: auto;
  flex-shrink: 0;
  filter: drop-shadow(0 8px 24px rgba(0,0,0,0.3));
}

.hero-badge {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #93c5fd;
  margin-bottom: 0.6rem;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: 1rem;
}

.hero-sub {
  font-size: 1.05rem;
  color: #bfdbfe;
  line-height: 1.65;
  max-width: 520px;
  margin-bottom: 1.8rem;
}

.hero-actions { display: flex; gap: 0.8rem; flex-wrap: wrap; }

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.6rem 1.3rem;
  border-radius: 7px;
  transition: all 0.15s;
  cursor: pointer;
}

.btn-primary {
  background: #fff;
  color: var(--navy);
}
.btn-primary:hover { background: #e0e7ff; text-decoration: none; }

.btn-secondary {
  background: rgba(255,255,255,0.12);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.25);
}
.btn-secondary:hover { background: rgba(255,255,255,0.2); text-decoration: none; }

.btn-sm { font-size: 0.82rem; padding: 0.45rem 1rem; }
.btn-sm.btn-primary { background: var(--accent); color: #fff; }
.btn-sm.btn-primary:hover { background: var(--accent-hover); }

/* ── Sections ── */
.section { padding: 4rem 0; }
.section-alt { background: var(--surface); }

.section-title {
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--navy);
  margin-bottom: 1.4rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border);
}

p { margin-bottom: 1rem; color: var(--text); }
p:last-child { margin-bottom: 0; }

/* ── Feature Grid ── */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: 1.6rem;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.3rem;
  box-shadow: var(--shadow);
}

.feature-icon {
  font-size: 1.1rem;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.feature-card h3 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  color: var(--navy);
}

.feature-card p {
  font-size: 0.875rem;
  color: var(--muted);
  margin: 0;
}

/* ── Install Cards ── */
.option-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.4rem 1.6rem;
  margin-bottom: 1.2rem;
  box-shadow: var(--shadow);
}

.option-header {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  margin-bottom: 0.8rem;
}

.option-tag {
  background: var(--navy);
  color: #fff;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.2rem 0.55rem;
  border-radius: 4px;
}

.option-label {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--navy);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.recommended {
  font-size: 0.7rem;
  font-weight: 600;
  background: #dcfce7;
  color: #166534;
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
}

pre {
  background: var(--code-bg);
  color: var(--code-text);
  border-radius: 7px;
  padding: 1rem 1.2rem;
  overflow-x: auto;
  font-family: "JetBrains Mono", "Fira Code", "Cascadia Code", monospace;
  font-size: 0.83rem;
  line-height: 1.65;
  margin: 0.7rem 0;
}

code {
  background: var(--accent-light);
  color: var(--accent);
  font-family: "JetBrains Mono", "Fira Code", monospace;
  font-size: 0.82em;
  padding: 0.12em 0.4em;
  border-radius: 4px;
}

pre code { background: none; color: inherit; padding: 0; font-size: inherit; }

.os-tabs { display: flex; flex-direction: column; gap: 0.8rem; }

.os-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--muted);
  margin-bottom: 0.3rem;
}

.hint {
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 0.6rem;
}

/* ── Paper ── */
.paper-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.6rem 1.8rem;
  box-shadow: var(--shadow);
}

.paper-meta {
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.paper-title {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 0.4rem;
  color: var(--navy);
}

.paper-title a { color: var(--navy); }
.paper-title a:hover { color: var(--accent); text-decoration: none; }

.paper-authors {
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 1rem;
}

/* ── Applications ── */
.app-list {
  list-style: none;
  margin-top: 0.8rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.app-list li {
  padding: 0.6rem 1rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 7px;
  font-size: 0.9rem;
  color: var(--text);
}


/* ── Collaborate ── */
.collab-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: 1.2rem;
}

.collab-item {
  background: var(--bg);
  border: 1px solid var(--border);
  border-top: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.1rem 1.2rem;
  font-size: 0.875rem;
  color: var(--text);
  font-weight: 500;
}

/* ── Contact ── */
.contact-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.8rem;
  box-shadow: var(--shadow);
}

.contact-card strong {
  display: block;
  font-size: 1rem;
  color: var(--navy);
  margin-bottom: 0.2rem;
}

.contact-card p {
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 0.4rem;
}

/* ── Footer ── */
.footer {
  background: var(--navy);
  color: #94a3b8;
  padding: 1.5rem 2rem;
}

.footer .inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.82rem;
}

.footer a { color: #94a3b8; }
.footer a:hover { color: #fff; text-decoration: none; }

/* ── Responsive ── */
@media (max-width: 700px) {
  .hero-inner { flex-direction: column; text-align: center; gap: 1.5rem; }
  .hero h1 { font-size: 2.2rem; }
  .hero-sub { margin: 0 auto 1.5rem; }
  .hero-actions { justify-content: center; }
  .feature-grid, .collab-grid { grid-template-columns: 1fr; }
  .os-tabs { grid-template-columns: 1fr; }
  .nav-links { gap: 0.8rem; }
  .nav-links a:not(.nav-github) { display: none; }
  .footer .inner { flex-direction: column; gap: 0.5rem; text-align: center; }
}