/* ==========================================================================
   Gravitys — Liquid Glass Theme
   Lightweight, framework-free, tuned to stay smooth on a Raspberry Pi.
   ========================================================================== */

:root {
  --bg-top: #05070d;
  --bg-mid: #0a0f1f;
  --bg-bottom: #0b1330;
  --accent: #5b8cff;
  --accent-soft: rgba(91, 140, 255, 0.35);
  --text-primary: #f4f6fb;
  --text-secondary: rgba(244, 246, 251, 0.68);
  --text-muted: rgba(244, 246, 251, 0.45);
  --glass-bg: rgba(255, 255, 255, 0.06);
  --glass-bg-strong: rgba(255, 255, 255, 0.09);
  --glass-border: rgba(255, 255, 255, 0.12);
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
  --radius-lg: 24px;
  --radius-md: 16px;
  --radius-sm: 10px;
  --font-stack: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
    Roboto, Helvetica, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-stack);
  color: var(--text-primary);
  background: radial-gradient(
      circle at 15% -10%,
      rgba(91, 140, 255, 0.18),
      transparent 45%
    ),
    radial-gradient(
      circle at 90% 10%,
      rgba(120, 80, 255, 0.14),
      transparent 40%
    ),
    linear-gradient(180deg, var(--bg-top) 0%, var(--bg-mid) 45%, var(--bg-bottom) 100%);
  background-attachment: fixed;
  min-height: 100vh;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
  display: block;
}

.container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------------- Glass building block ---------------- */
.glass {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--glass-shadow);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  backdrop-filter: blur(18px) saturate(140%);
}

/* ---------------- Header / Nav ---------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  padding: 14px 0;
}

.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 22px;
  border-radius: var(--radius-md);
}

.logo {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.nav-links {
  display: flex;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  display: inline-block;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.92rem;
  color: var(--text-secondary);
  transition: background 0.2s ease, color 0.2s ease;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  background: var(--glass-bg-strong);
  color: var(--text-primary);
}

.nav-toggle {
  display: none;
}

/* ---------------- Hero ---------------- */
.hero {
  padding: 96px 0 64px;
  text-align: center;
}

.hero-eyebrow {
  display: inline-block;
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 22px;
}

.hero h1 {
  font-size: clamp(2.4rem, 6vw, 3.6rem);
  margin: 0 0 18px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.hero p {
  max-width: 560px;
  margin: 0 auto 32px;
  color: var(--text-secondary);
  font-size: 1.05rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 26px;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 600;
  border: 1px solid var(--glass-border);
  cursor: pointer;
  transition: transform 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), #7a5bff);
  color: #ffffff;
  border: none;
  box-shadow: 0 10px 30px var(--accent-soft);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 34px var(--accent-soft);
}

.btn-ghost {
  background: var(--glass-bg);
  color: var(--text-primary);
}

.btn-ghost:hover {
  background: var(--glass-bg-strong);
  transform: translateY(-2px);
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.button-row-centered {
  justify-content: center;
}

/* ---------------- Sections ---------------- */
section {
  padding: 56px 0;
}

.section-title {
  font-size: clamp(1.5rem, 3.2vw, 2rem);
  font-weight: 700;
  margin: 0 0 10px;
  letter-spacing: -0.01em;
}

.section-subtitle {
  color: var(--text-secondary);
  margin: 0 0 36px;
  max-width: 620px;
}

/* ---------------- Project cards ---------------- */
.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 22px;
}

.project-card {
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: transform 0.25s ease, border-color 0.25s ease;
}

.project-card:hover {
  transform: translateY(-4px);
  border-color: rgba(91, 140, 255, 0.4);
}

.project-card .project-title {
  font-size: 1.3rem;
  font-weight: 700;
  margin: 0;
}

.project-card .project-subtitle {
  color: var(--accent);
  font-size: 0.9rem;
  font-weight: 600;
  margin: 0;
}

.project-card .project-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin: 0;
}

.feature-list {
  list-style: none;
  margin: 4px 0 8px;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.feature-list li {
  font-size: 0.8rem;
  color: var(--text-secondary);
  background: var(--glass-bg-strong);
  border: 1px solid var(--glass-border);
  border-radius: 999px;
  padding: 5px 12px;
}

.project-card .btn {
  align-self: flex-start;
  margin-top: 6px;
}

.project-card .project-title {
  font-size: 1.7rem;
}

.project-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px;
  margin-top: 8px;
}

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-primary);
  font-weight: 600;
  text-decoration: underline;
  text-decoration-color: var(--accent-soft);
  text-underline-offset: 4px;
}

.text-link:hover,
.text-link:focus-visible {
  color: #b8ccff;
}

.section-heading-block {
  margin-bottom: 28px;
}

.section-heading-block .section-subtitle {
  margin-bottom: 0;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.guide-card {
  padding: 24px;
}

.guide-step {
  display: inline-block;
  margin-bottom: 14px;
  color: #a9c0ff;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.guide-card h3,
.content-section h2 {
  margin: 0 0 10px;
  font-size: 1.12rem;
}

.guide-card p,
.content-section p,
.content-section li {
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.notice {
  max-width: 850px;
  margin: 24px 0 16px;
  padding: 16px 18px;
  color: var(--text-secondary);
  background: rgba(91, 140, 255, 0.08);
  border: 1px solid rgba(91, 140, 255, 0.22);
  border-radius: var(--radius-md);
  font-size: 0.92rem;
}

.notice strong {
  color: var(--text-primary);
}

.content-page {
  max-width: 860px;
  margin: 0 auto;
}

.content-page .page-card {
  padding: clamp(24px, 5vw, 48px);
}

.content-page .page-intro {
  color: var(--text-secondary);
  font-size: 1.08rem;
}

.content-section {
  margin-top: 36px;
}

.content-section ol,
.content-section ul {
  display: grid;
  gap: 12px;
  padding-left: 24px;
}

.content-section li {
  padding-left: 4px;
}

.content-section .button-row {
  margin-top: 18px;
}

.faq-list {
  display: grid;
  gap: 12px;
  margin-top: 16px;
}

.faq-list details {
  padding: 16px 18px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
}

.faq-list summary {
  cursor: pointer;
  font-weight: 600;
}

.faq-list details p {
  margin-top: 10px;
}

.page-updated {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ---------------- About ---------------- */
.about-card {
  padding: 36px;
}

.about-card p {
  color: var(--text-secondary);
  margin: 0 0 14px;
}

.about-card p:last-child {
  margin-bottom: 0;
}

/* ---------------- Footer ---------------- */
.site-footer {
  padding: 40px 0 56px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 18px;
  margin-bottom: 14px;
  list-style: none;
  padding: 0;
}

.footer-links a {
  color: var(--text-secondary);
  transition: color 0.2s ease;
}

.footer-links a:hover {
  color: var(--text-primary);
}

/* ---------------- Simple content page (privacy / contact) ---------------- */
.page-card {
  padding: 40px;
  margin: 24px 0 56px;
}

.page-card h1 {
  margin-top: 0;
  font-size: clamp(1.8rem, 4vw, 2.4rem);
}

.page-card h2 {
  font-size: 1.15rem;
  margin: 32px 0 10px;
}

.page-card p,
.page-card li {
  color: var(--text-secondary);
  font-size: 0.96rem;
}

.page-card a.inline-link {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.back-link {
  display: inline-block;
  margin-bottom: 24px;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.back-link:hover {
  color: var(--text-primary);
}

/* ---------------- Responsive ---------------- */
@media (max-width: 720px) {
  .nav-links {
    position: absolute;
    top: 64px;
    right: 24px;
    left: 24px;
    flex-direction: column;
    padding: 10px;
    background: var(--glass-bg-strong);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
    display: none;
  }

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

  .nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    border-radius: var(--radius-sm);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    cursor: pointer;
  }

  .hero {
    padding: 64px 0 44px;
  }

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

  .project-actions {
    align-items: flex-start;
    flex-direction: column;
  }
}

/* Respect users who prefer reduced motion */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .project-card,
  .btn {
    transition: none;
  }
}