/* ============================================================
   TreamOS Website — Main Stylesheet
   ============================================================ */

/* ── Custom Properties ── */
:root {
  --bg:          #0a0c10;
  --bg-surface:  #10131a;
  --bg-elevated: #161b25;
  --border:      rgba(255, 255, 255, 0.08);
  --text:        #e2e8f0;
  --text-muted:  #8892a4;
  --accent:      #5b9bd5;
  --accent-dark: #3a7bbf;
  --accent-glow: rgba(91, 155, 213, 0.25);
  --green:       #4ade80;
  --red:         #f87171;
  --yellow:      #facc15;
  --radius:      10px;
  --radius-lg:   16px;
  --shadow:      0 4px 24px rgba(0, 0, 0, 0.4);
  --transition:  0.25s ease;
  --font-sans:   'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono:   'Fira Code', 'Cascadia Code', 'Consolas', monospace;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img, svg { display: block; }

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

ul { list-style: none; }

/* ── Utility ── */
.container {
  width: 100%;
  max-width: 1140px;
  margin-inline: auto;
  padding-inline: clamp(1rem, 5vw, 2rem);
}

.text-gradient {
  background: linear-gradient(135deg, var(--accent) 0%, #8b5cf6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ── Navigation ── */
.site-header {
  position: fixed;
  inset-block-start: 0;
  inset-inline: 0;
  z-index: 100;
  transition: background var(--transition), backdrop-filter var(--transition), border-color var(--transition);
  border-bottom: 1px solid transparent;
}

.site-header.scrolled {
  background: rgba(10, 12, 16, 0.85);
  backdrop-filter: blur(16px);
  border-bottom-color: var(--border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  gap: 1.5rem;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}

.nav-logo-text { color: var(--text); }

.nav-menu {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav-link {
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  color: var(--text-muted);
  transition: color var(--transition), background var(--transition);
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--text);
  background: var(--bg-elevated);
  outline: none;
}

.nav-link--cta {
  color: var(--accent) !important;
  border: 1px solid rgba(91, 155, 213, 0.35);
}

.nav-link--cta:hover,
.nav-link--cta:focus-visible {
  background: var(--accent-glow) !important;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.35rem;
  border-radius: var(--radius);
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1.4rem;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
  border: 1px solid transparent;
}

.btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.btn--primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 0 20px var(--accent-glow);
}

.btn--primary:hover {
  background: var(--accent-dark);
  box-shadow: 0 0 28px rgba(91, 155, 213, 0.45);
  transform: translateY(-1px);
}

.btn--secondary {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.btn--secondary:hover {
  background: var(--bg-elevated);
  border-color: rgba(255, 255, 255, 0.15);
  transform: translateY(-1px);
}

/* ── Hero ── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  padding-block: 7rem 4rem;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}

#hero-canvas {
  width: 100%;
  height: 100%;
}

.hero-content {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1.5rem;
  max-width: 700px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  padding: 0.3rem 0.85rem;
  border-radius: 100px;
  background: rgba(91, 155, 213, 0.12);
  border: 1px solid rgba(91, 155, 213, 0.3);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--text);
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.15rem);
  color: var(--text-muted);
  max-width: 560px;
  line-height: 1.75;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.hero-stats {
  display: flex;
  gap: 3rem;
  padding-top: 0.5rem;
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.stat-value {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.hero-scroll-hint {
  position: absolute;
  bottom: 2.5rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  animation: float 2.5s ease-in-out infinite;
}

.scroll-dot {
  animation: scroll-bounce 2.5s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50%       { transform: translateX(-50%) translateY(6px); }
}

@keyframes scroll-bounce {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(8px); }
}

/* ── Sections ── */
.section {
  padding-block: clamp(4rem, 8vw, 7rem);
}

.section--dark {
  background: var(--bg-surface);
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin-inline: auto;
  margin-bottom: clamp(2.5rem, 5vw, 4rem);
}

.section-tag {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.75;
}

.section-subtitle--left { text-align: left; }

/* ── About Grid ── */
.about-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
}

.about-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.about-card:hover {
  border-color: rgba(91, 155, 213, 0.35);
  transform: translateY(-3px);
  box-shadow: var(--shadow);
}

.about-card-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius);
  background: rgba(91, 155, 213, 0.1);
  border: 1px solid rgba(91, 155, 213, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
}

.about-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.about-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ── Architecture Diagram ── */
.arch-diagram {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  max-width: 860px;
  margin-inline: auto;
}

.arch-layer {
  padding: 1.5rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.arch-layer--user   { background: rgba(91, 155, 213, 0.06); }
.arch-layer--kernel { background: rgba(139, 92, 246, 0.08); }
.arch-layer--hw     { background: rgba(255, 255, 255, 0.03); }

.arch-layer-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
}

.arch-apps {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.arch-apps--services { margin-top: -0.2rem; }

.arch-box {
  padding: 0.4rem 0.9rem;
  border-radius: var(--radius);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text);
}

.arch-box--service {
  background: rgba(91, 155, 213, 0.1);
  border-color: rgba(91, 155, 213, 0.25);
  color: var(--accent);
}

.arch-box--kernel {
  background: rgba(139, 92, 246, 0.12);
  border-color: rgba(139, 92, 246, 0.3);
  color: #a78bfa;
}

.arch-box--hw {
  background: rgba(255, 255, 255, 0.04);
  border-color: rgba(255, 255, 255, 0.1);
  color: var(--text-muted);
}

.arch-ipc {
  background: var(--bg-surface);
  padding: 0.5rem 2rem;
  border-block: 1px solid var(--border);
}

.arch-ipc-line {
  position: relative;
  display: flex;
  align-items: center;
  height: 40px;
}

.arch-ipc-label {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  background: var(--bg-surface);
  padding-inline: 0.75rem;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  white-space: nowrap;
}

/* ── Community Section ── */
.community-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
}

.community-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  transition: border-color var(--transition), transform var(--transition);
}

.community-card:hover {
  border-color: rgba(91, 155, 213, 0.35);
  transform: translateY(-3px);
}

.community-card-icon {
  color: var(--accent);
}

.community-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.community-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  flex: 1;
  line-height: 1.7;
}

.community-card-link {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--accent);
  transition: opacity var(--transition);
}

.community-card-link:hover { opacity: 0.75; }

/* ── Contribute Section ── */
.contribute-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
}

.contribute-text {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.contribute-list {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}

.contribute-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.contribute-list li svg {
  flex-shrink: 0;
  margin-top: 0.1rem;
}

.contribute-list strong { color: var(--text); }

.contribute-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding-top: 0.5rem;
}

/* ── Terminal ── */
.terminal {
  background: #0d1117;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow), 0 0 40px rgba(91, 155, 213, 0.08);
  font-family: var(--font-mono);
  font-size: 0.83rem;
}

.terminal-header {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.75rem 1rem;
  background: #161b22;
  border-bottom: 1px solid var(--border);
}

.terminal-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.terminal-dot--red    { background: var(--red); }
.terminal-dot--yellow { background: var(--yellow); }
.terminal-dot--green  { background: var(--green); }

.terminal-title {
  margin-left: auto;
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-sans);
}

.terminal-body {
  padding: 1.25rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  color: var(--text);
}

.term-prompt {
  color: var(--green);
  margin-right: 0.5rem;
  user-select: none;
}

.term-output {
  color: var(--text-muted);
  padding-left: 1.2rem;
}

.term-ok { color: var(--green); }

.term-blink::after {
  content: '';
  display: inline-block;
  width: 8px;
  height: 1em;
  background: var(--accent);
  margin-left: 2px;
  vertical-align: text-bottom;
  animation: blink 1s step-end infinite;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0; }
}

/* ── Footer ── */
.site-footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
  padding-block: 3rem 1.5rem;
}

.footer-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 3rem;
  align-items: start;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-tagline {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

.footer-nav {
  display: flex;
  gap: 3rem;
}

.footer-nav-col h4 {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.footer-nav-col ul {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-nav-col a {
  font-size: 0.875rem;
  color: var(--text-muted);
  transition: color var(--transition);
}

.footer-nav-col a:hover { color: var(--text); }

.footer-bottom {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

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

/* ── Responsive ── */
@media (max-width: 900px) {
  .contribute-layout {
    grid-template-columns: 1fr;
  }
  .footer-inner {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .nav-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    inset-block-start: 68px;
    inset-inline: 0;
    background: rgba(10, 12, 16, 0.97);
    backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: stretch;
    padding: 1rem;
    gap: 0.25rem;
    border-bottom: 1px solid var(--border);
    transform: translateY(-110%);
    opacity: 0;
    transition: transform 0.3s ease, opacity 0.3s ease;
    pointer-events: none;
  }

  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-link {
    padding: 0.65rem 1rem;
    font-size: 1rem;
  }

  .hero-stats {
    gap: 1.75rem;
  }

  .footer-nav {
    flex-direction: column;
    gap: 1.5rem;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .arch-diagram {
    font-size: 0.9rem;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 2.2rem;
  }

  .hero-stats {
    gap: 1.25rem;
  }

  .stat-value {
    font-size: 1.6rem;
  }
}

/* ── Scroll Animation ── */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}