:root {
  --bg: #ffffff;
  --bg-secondary: #f7f6f2;
  --bg-tertiary: #efeee8;
  --bg-dark: #0B1F3A;
  --text-primary: #1a1a1a;
  --text-secondary: #5f5e5a;
  --text-tertiary: #888780;
  --text-on-dark: #ffffff;
  --text-on-dark-muted: rgba(255,255,255,0.72);
  --border: rgba(0,0,0,0.12);
  --border-strong: rgba(0,0,0,0.25);
  --accent-na: #F5C04A;
  --accent-condor: #1E7D5E;
  --accent-condor-deep: #14664C;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--text-primary);
  background: var(--bg-tertiary);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

.page {
  max-width: 1200px;
  margin: 0 auto;
  background: var(--bg);
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.site-header {
  position: relative;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 32px;
  background: var(--bg-dark);
  color: var(--text-on-dark);
}

.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: rgba(255,255,255,0.06);
  border: 0.5px solid rgba(245,192,74,0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.brand-text { line-height: 1.2; }
.brand-text .title { font-size: 14px; font-weight: 500; }
.brand-text .subtitle { font-size: 12px; color: var(--text-on-dark-muted); }
.brand a { text-decoration: none; color: inherit; }

nav { display: flex; gap: 28px; }
nav a {
  color: var(--text-on-dark-muted);
  text-decoration: none;
  font-size: 14px;
  padding-bottom: 3px;
}
nav a.active {
  color: var(--text-on-dark);
  font-weight: 500;
  border-bottom: 2px solid var(--accent-na);
}
nav a:hover { color: var(--text-on-dark); }
.menu-icon { display: none; border: 0; background: transparent; padding: 4px; font: inherit; line-height: 1; }

.page-banner {
  background: var(--bg-dark);
  padding: 24px 32px 20px;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}
.breadcrumb {
  font-size: 12px;
  color: var(--text-on-dark-muted);
  margin-bottom: 14px;
  letter-spacing: 0.02em;
}
.breadcrumb a { color: var(--text-on-dark-muted); text-decoration: none; }
.breadcrumb a:hover { color: var(--accent-na); }
.breadcrumb .sep { margin: 0 6px; opacity: 0.5; }
.page-banner h1 {
  font-size: 30px;
  font-weight: 500;
  color: var(--text-on-dark);
  margin: 0 0 10px;
  line-height: 1.25;
}
.page-banner .tagline {
  font-size: 15px;
  color: var(--text-on-dark-muted);
  margin: 0;
  line-height: 1.6;
  max-width: 760px;
}
.banner-meta { display: flex; gap: 18px; margin-top: 14px; flex-wrap: wrap; }
.banner-meta-item { font-size: 13px; color: var(--text-on-dark-muted); }
.banner-meta-item strong { color: var(--text-on-dark); font-weight: 500; }

section {
  padding: 26px 32px;
  border-bottom: 0.5px solid var(--border);
}
section:last-of-type { border-bottom: none; }

.tool-intro { padding-bottom: 18px; }
.explain {
  margin: 0;
  font-size: 14px;
  color: var(--text-secondary);
  max-width: 900px;
  line-height: 1.6;
}

.tool-workspace { padding-top: 18px; }
#app {
  display: flex;
  align-items: stretch;
  justify-content: flex-start;
  overflow-x: auto;
  border: 0.5px solid var(--border);
  border-radius: 8px;
  background: var(--bg-secondary);
}

#plot-wrap {
  flex: 0 0 auto;
  position: relative;
  padding: 16px;
  background: #fff;
}
#plot { width: 860px; height: 600px; }

#status {
  position: absolute;
  top: 8px;
  left: 12px;
  font-size: 12px;
  color: var(--text-tertiary);
  background: rgba(255, 255, 255, 0.9);
  padding: 2px 8px;
  border-radius: 4px;
  pointer-events: none;
}

#panel {
  width: 250px;
  flex: 0 0 250px;
  padding: 14px;
  border-left: 0.5px solid var(--border);
  background: var(--bg-secondary);
  overflow-y: auto;
}

.group { margin-bottom: 16px; }
.group > label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 5px;
}

.views { display: flex; flex-direction: column; gap: 6px; }
.view-btn, #add-btn, #png-btn, #reset-btn {
  min-height: 38px;
  padding: 8px 10px;
  border: 0.5px solid var(--border-strong);
  background: #fff;
  border-radius: 6px;
  color: var(--text-primary);
  cursor: pointer;
  font: inherit;
  font-size: 13px;
}
.view-btn.active {
  background: var(--accent-condor);
  color: #fff;
  border-color: var(--accent-condor);
}
#png-btn {
  width: 100%;
  background: var(--accent-condor);
  color: #fff;
  border-color: var(--accent-condor);
}
#png-btn:hover, .view-btn.active:hover { background: var(--accent-condor-deep); }
#add-btn { width: 100%; }
#reset-btn { width: 100%; margin-top: 8px; }

input[type="range"] { width: 100%; }
input[type="number"], input[type="text"] {
  width: 100%;
  min-height: 34px;
  padding: 5px 6px;
  border: 0.5px solid var(--border-strong);
  border-radius: 5px;
  color: var(--text-primary);
  font: inherit;
  font-size: 13px;
  background: #fff;
}

.add-link .row { display: flex; gap: 6px; margin-bottom: 6px; }
.hint { font-size: 11px; color: var(--text-tertiary); margin: 6px 0 0; }

#links label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 500;
  margin: 3px 0;
  color: var(--text-secondary);
}
#links .swatch { width: 12px; height: 12px; border-radius: 3px; display: inline-block; }

footer {
  padding: 12px 32px;
  background: var(--bg-dark);
  color: var(--text-on-dark-muted);
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  align-items: center;
}
.footer-left { display: flex; align-items: center; gap: 12px; }
.nsf-logo { width: 44px; height: 44px; object-fit: contain; }
footer a { color: var(--text-on-dark-muted); }
footer a:hover { color: var(--text-on-dark); }

@media (max-width: 680px) {
  .site-header { padding: 14px 18px; flex-wrap: wrap; }
  nav { display: none; }
  nav.mobile-open {
    display: flex;
    flex-basis: 100%;
    flex-direction: column;
    gap: 0;
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid rgba(255,255,255,0.12);
  }
  nav.mobile-open a { padding: 9px 0; }
  .menu-icon { display: block; font-size: 22px; cursor: pointer; color: var(--text-on-dark); }
  .page-banner { padding: 18px 18px 16px; }
  .page-banner h1 { font-size: 22px; }
  section { padding: 20px 18px; }
  #plot { width: 820px; height: 560px; }
  footer { flex-direction: column; gap: 10px; padding: 12px 18px; align-items: flex-start; }
}