/* ============================================================
   cidr.theadminstack.com — Styles
   Design tokens match theadminstack.com v4.0
   No external dependencies — system font stack
   ============================================================ */

/* ── Tokens (light) ─────────────────────────────────────────── */
:root {
  --bg:        #f9fafb;
  --bg-2:      #f3f4f6;
  --bg-3:      #e5e7eb;

  --surface:   #ffffff;
  --surface-2: rgba(0,0,0,0.025);
  --surface-3: rgba(0,0,0,0.05);

  --border:    rgba(0,0,0,0.07);
  --border-2:  rgba(0,0,0,0.12);
  --border-3:  rgba(0,0,0,0.22);

  --accent:    #111827;
  --accent-2:  #374151;
  --accent-dim: rgba(0,0,0,0.06);

  --green:     #16a34a;
  --green-bg:  #dcfce7;
  --red:       #dc2626;
  --red-bg:    #fee2e2;
  --orange:    #d97706;
  --orange-bg: #fef3c7;

  --text:      #111827;
  --text-2:    #4b5563;
  --text-3:    #9ca3af;
  --text-4:    #d1d5db;

  --font-body: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;

  --r-sm:  6px;
  --r-md:  10px;
  --r-lg:  14px;
  --r-pill: 100px;

  --shadow-sm:  0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md:  0 4px 12px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.04);

  --t-mid: 200ms ease;

  --nav-h: 60px;
  --container: 1100px;

  /* CIDR-specific */
  --bit-net:   #111827;
  --bit-host:  #4b5563;
  --bit-net-bg:  rgba(17,24,39,0.12);
  --bit-host-bg: rgba(75,85,99,0.07);
}

/* ── Tokens (dark) ───────────────────────────────────────────── */
html.dark {
  --bg:        #0f1117;
  --bg-2:      #161b27;
  --bg-3:      #1e2433;

  --surface:   #1a2030;
  --surface-2: rgba(255,255,255,0.03);
  --surface-3: rgba(255,255,255,0.06);

  --border:    rgba(255,255,255,0.07);
  --border-2:  rgba(255,255,255,0.12);
  --border-3:  rgba(255,255,255,0.22);

  --accent:    #e5e7eb;
  --accent-2:  #9ca3af;
  --accent-dim: rgba(255,255,255,0.06);

  --green:     #4ade80;
  --green-bg:  rgba(74,222,128,0.12);
  --red:       #f87171;
  --red-bg:    rgba(248,113,113,0.12);
  --orange:    #fbbf24;
  --orange-bg: rgba(251,191,36,0.12);

  --text:      #f3f4f6;
  --text-2:    #9ca3af;
  --text-3:    #6b7280;
  --text-4:    #374151;

  --bit-net:   #e5e7eb;
  --bit-host:  #6b7280;
  --bit-net-bg:  rgba(229,231,235,0.15);
  --bit-host-bg: rgba(107,114,128,0.10);
}

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

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

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ── Nav ─────────────────────────────────────────────────────── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-h);
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--t-mid);
}
.nav.scrolled { box-shadow: var(--shadow-sm); }

.nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 100%;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  text-decoration: none;
  flex-shrink: 0;
}
.nav-brand-mark {
  width: 32px; height: 32px;
  background: var(--accent);
  color: var(--surface);
  border-radius: var(--r-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  flex-shrink: 0;
}
html.dark .nav-brand-mark { background: var(--accent); color: var(--bg); }

.nav-brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}
.nav-brand-name {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
}
.nav-brand-sub {
  font-size: 0.7rem;
  color: var(--text-3);
  font-family: var(--font-mono);
}

.nav-sep { flex: 1; }

.nav-back {
  font-size: 0.8125rem;
  color: var(--text-2);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.375rem 0.75rem;
  border: 1px solid var(--border-2);
  border-radius: var(--r-pill);
  transition: color var(--t-mid), border-color var(--t-mid), background var(--t-mid);
  white-space: nowrap;
}
.nav-back:hover {
  color: var(--text);
  border-color: var(--border-3);
  background: var(--surface-2);
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border-2);
  border-radius: var(--r-sm);
  width: 36px; height: 36px;
  cursor: pointer;
  color: var(--text-2);
  display: flex; align-items: center; justify-content: center;
  transition: color var(--t-mid), border-color var(--t-mid), background var(--t-mid);
  flex-shrink: 0;
}
.theme-toggle:hover { color: var(--text); background: var(--surface-2); }

/* ── Hero ────────────────────────────────────────────────────── */
.hero {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 2.5rem 1.5rem 2rem;
  text-align: center;
}
.hero-wrap { max-width: var(--container); margin: 0 auto; }

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-2);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  background: var(--bg-2);
  border: 1px solid var(--border-2);
  border-radius: var(--r-pill);
  padding: 0.25rem 0.75rem;
  margin-bottom: 1rem;
}

.hero h1 {
  font-size: clamp(1.5rem, 4vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text);
  line-height: 1.15;
  margin-bottom: 0.625rem;
}

.hero-sub {
  font-size: 0.9375rem;
  color: var(--text-2);
  max-width: 520px;
  margin: 0 auto;
}

/* ── Main layout ─────────────────────────────────────────────── */
main {
  flex: 1;
  max-width: var(--container);
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}

/* ── Tab bar ─────────────────────────────────────────────────── */
.tab-bar {
  display: flex;
  gap: 0.25rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 0.3rem;
  margin-bottom: 1.75rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.tab-btn {
  flex: 1;
  min-width: 0;
  background: none;
  border: none;
  border-radius: var(--r-md);
  padding: 0.5rem 0.875rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-2);
  cursor: pointer;
  white-space: nowrap;
  transition: color var(--t-mid), background var(--t-mid);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.375rem;
}
.tab-btn:hover { color: var(--text); background: var(--surface-2); }
.tab-btn.active {
  background: var(--accent);
  color: var(--surface);
}
html.dark .tab-btn.active { color: var(--bg); }

.tab-icon { font-size: 0.875rem; }

/* ── Tab panels ──────────────────────────────────────────────── */
.tab-panel { display: block; }
.tab-panel[hidden] { display: none; }

/* ── Card ────────────────────────────────────────────────────── */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 1.5rem;
  margin-bottom: 1.25rem;
}
.card-title {
  font-size: 0.875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-3);
  margin-bottom: 1rem;
}

/* ── Form elements ───────────────────────────────────────────── */
.input-row {
  display: flex;
  gap: 0.625rem;
  align-items: flex-end;
  flex-wrap: wrap;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
  flex: 1;
  min-width: 180px;
}

label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-2);
}

input[type="text"],
input[type="number"],
textarea {
  width: 100%;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  background: var(--bg);
  border: 1px solid var(--border-2);
  border-radius: var(--r-md);
  padding: 0.6rem 0.875rem;
  color: var(--text);
  outline: none;
  transition: border-color var(--t-mid), box-shadow var(--t-mid);
}
input:focus, textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}
input::placeholder, textarea::placeholder { color: var(--text-3); }

textarea {
  font-size: 0.875rem;
  resize: vertical;
  min-height: 110px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.875rem;
  font-weight: 600;
  border: none;
  border-radius: var(--r-md);
  padding: 0.65rem 1.25rem;
  cursor: pointer;
  white-space: nowrap;
  transition: opacity var(--t-mid), transform var(--t-mid);
}
.btn:active { transform: scale(0.98); }
.btn-primary {
  background: var(--accent);
  color: var(--surface);
}
html.dark .btn-primary { color: var(--bg); }
.btn-primary:hover { opacity: 0.88; }

.btn-ghost {
  background: var(--surface-3);
  color: var(--text-2);
  border: 1px solid var(--border-2);
}
.btn-ghost:hover { background: var(--surface-2); color: var(--text); }

/* ── Example buttons ─────────────────────────────────────────── */
.examples {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
  margin-top: 0.875rem;
}
.examples-label {
  font-size: 0.75rem;
  color: var(--text-3);
  display: flex;
  align-items: center;
  margin-right: 0.25rem;
}
.example-btn {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  background: var(--bg-2);
  border: 1px solid var(--border-2);
  border-radius: var(--r-pill);
  padding: 0.2rem 0.625rem;
  cursor: pointer;
  color: var(--text-2);
  transition: background var(--t-mid), color var(--t-mid);
}
.example-btn:hover { background: var(--bg-3); color: var(--text); }

/* ── Result area ─────────────────────────────────────────────── */
.result-area {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 1.25rem;
  min-height: 60px;
  transition: all var(--t-mid);
}
.result-area:empty::before {
  content: 'Results will appear here';
  color: var(--text-3);
  font-size: 0.875rem;
}

/* ── Result table ────────────────────────────────────────────── */
.result-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}
.result-table th {
  text-align: left;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-3);
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
}
.result-table td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.result-table tr:last-child td { border-bottom: none; }
.result-table tr:hover td { background: var(--surface-2); }

.rt-label {
  color: var(--text-2);
  font-size: 0.8125rem;
  white-space: nowrap;
  width: 45%;
}
.rt-value { color: var(--text); font-weight: 500; }
.rt-note  { color: var(--text-3); font-size: 0.8rem; }

.mono { font-family: var(--font-mono); }
.txt-green { color: var(--green); font-weight: 600; }
.txt-red   { color: var(--red);   font-weight: 600; }

/* ── Range bar ───────────────────────────────────────────────── */
.range-bar-wrap { margin-top: 1rem; }
.range-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  background: linear-gradient(90deg, var(--bg-3) 0%, var(--bg-2) 15%, var(--bg-2) 85%, var(--bg-3) 100%);
  border: 1px solid var(--border-2);
  border-radius: var(--r-pill);
  padding: 0.5rem 1rem;
  font-size: 0.78rem;
  font-family: var(--font-mono);
  overflow: hidden;
}
.rb-net, .rb-bcast { color: var(--text-3); white-space: nowrap; }
.rb-range { color: var(--text); font-weight: 600; text-align: center; flex: 1; }

/* ── Alerts ──────────────────────────────────────────────────── */
.alert {
  border-radius: var(--r-md);
  padding: 0.75rem 1rem;
  font-size: 0.875rem;
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
}
.alert-error { background: var(--red-bg); color: var(--red); border: 1px solid var(--red); }
.alert-warn  { background: var(--orange-bg); color: var(--orange); border: 1px solid var(--orange); margin-bottom: 1rem; }
.alert-icon  { font-weight: 700; flex-shrink: 0; }

/* ── Tags ────────────────────────────────────────────────────── */
.tag {
  display: inline-block;
  background: var(--accent-dim);
  color: var(--text);
  border-radius: var(--r-pill);
  padding: 0.2rem 0.625rem;
  font-size: 0.8rem;
  font-family: var(--font-mono);
  font-weight: 600;
}

/* ── Subnet splitter ─────────────────────────────────────────── */
.prefix-row {
  display: flex;
  gap: 0.625rem;
  align-items: flex-end;
  flex-wrap: wrap;
}
.prefix-row .input-group { flex: 2; }
.prefix-input-group { flex: 0 0 140px; }

.prefix-hint {
  font-size: 0.78rem;
  font-family: var(--font-mono);
  color: var(--green);
  margin-top: 0.25rem;
  min-height: 1.2em;
}

.split-summary {
  font-size: 0.9rem;
  margin-bottom: 1rem;
  color: var(--text-2);
}
.split-summary strong { color: var(--text); }

/* Tree */
.subnet-tree {
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--surface);
  padding: 0.875rem 1rem;
  margin-bottom: 1rem;
  font-size: 0.875rem;
  font-family: var(--font-mono);
  overflow-x: auto;
}
.tree-node { padding: 0.2rem 0; display: flex; align-items: center; gap: 0.4rem; }
.tree-parent { font-weight: 700; color: var(--text); }
.tree-children { margin-left: 1.25rem; max-height: 260px; overflow-y: auto; }
.tree-child { color: var(--text-2); }
.tree-child:hover { color: var(--text); }
.tree-icon { color: var(--text-3); font-size: 0.7rem; }
.tree-connector { color: var(--text-4); }
.tree-meta { color: var(--text-3); font-size: 0.8rem; }

.split-table-wrap {
  margin-top: 0.75rem;
}
.split-table-wrap > summary {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-2);
  cursor: pointer;
  user-select: none;
  padding: 0.5rem 0;
}
.split-table-wrap > summary:hover { color: var(--text); }
.split-table { margin-top: 0.5rem; }

/* ── Binary display ──────────────────────────────────────────── */
.binary-display {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  overflow-x: auto;
}

.bin-row {
  display: flex;
  align-items: center;
  gap: 0;
  margin-bottom: 0.5rem;
}

.bin-octet {
  display: flex;
  align-items: center;
  gap: 2px;
  min-width: 160px;
  justify-content: center;
  flex: 1;
}

.bin-header .bin-octet-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-3);
  flex: 1;
  text-align: center;
}

.bin-decimal .bin-octet {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  border-bottom: 2px solid var(--border-2);
  padding-bottom: 0.375rem;
  margin-bottom: 0.125rem;
}

.bin-bit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px; height: 22px;
  border-radius: 3px;
  font-size: 0.8rem;
  font-weight: 600;
  transition: background var(--t-mid);
}

.bit-net {
  background: var(--bit-net-bg);
  color: var(--bit-net);
}
.bit-host {
  background: var(--bit-host-bg);
  color: var(--bit-host);
}

/* Right boundary marker */
.bit-boundary-right {
  border-right: 2px solid var(--red);
  margin-right: 2px;
}

.bin-dot {
  color: var(--text-3);
  font-size: 1rem;
  margin: 0 4px;
  align-self: center;
  padding-bottom: 4px;
}

.bin-legend {
  display: flex;
  gap: 1.5rem;
  font-size: 0.78rem;
  color: var(--text-3);
  margin: 0.75rem 0;
}
.legend-net  { color: var(--text-2); font-weight: 600; }
.legend-host { color: var(--text-3); }

.bin-mask-row, .bin-hex-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.82rem;
  margin-top: 0.375rem;
  flex-wrap: wrap;
}
.bin-mask-label {
  color: var(--text-3);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  min-width: 40px;
}
.bin-mask-octet { color: var(--text-2); }

/* ── Supernet ────────────────────────────────────────────────── */
.super-summary {
  text-align: center;
  padding: 1.25rem;
  background: var(--accent-dim);
  border-radius: var(--r-md);
  margin-bottom: 1.25rem;
}
.super-cidr {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.02em;
  margin-bottom: 0.25rem;
}
.super-meta { color: var(--text-2); font-size: 0.875rem; }

/* ── Footer ──────────────────────────────────────────────────── */
footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  text-align: center;
  padding: 1.25rem 1rem;
  font-size: 0.8rem;
  color: var(--text-3);
}
footer a { color: var(--text-2); text-decoration: none; }
footer a:hover { color: var(--text); text-decoration: underline; }

/* ── Responsive ──────────────────────────────────────────────── */
@media (max-width: 640px) {
  .hero { padding: 1.75rem 1rem 1.5rem; }
  main  { padding: 1.25rem 1rem 3rem; }
  .card { padding: 1rem; }

  .tab-btn { padding: 0.4rem 0.625rem; font-size: 0.75rem; }
  .tab-icon { display: none; }

  .bin-bit { width: 14px; height: 18px; font-size: 0.7rem; }
  .bin-octet { min-width: 120px; gap: 1px; }

  .super-cidr { font-size: 1.25rem; }

  .input-row, .prefix-row { flex-direction: column; }
  .input-group, .prefix-input-group { min-width: 0; width: 100%; }
}