/* ═══════════════════════════════════════════
   CIDR Calculator — Gradient Mix Theme
   Matching OpenSecTools aesthetic
   ═══════════════════════════════════════════ */

:root {
  --bg:        #06080d;
  --bg2:       #0c1018;
  --surface:   #111827;
  --surface2:  #1a2235;
  --border:    rgba(255,255,255,0.06);
  --border2:   rgba(255,255,255,0.10);
  --text:      #e2e8f0;
  --text2:     #94a3b8;
  --text3:     #64748b;
  --accent:    #a855f7;
  --accent-h:  #9333ea;
  --cyan:      #06b6d4;
  --rose:      #f43f5e;
  --green:     #10b981;
  --amber:     #f59e0b;
  --red:       #ef4444;
  --blue:      #3b82f6;
  --grad:      linear-gradient(135deg, #06b6d4, #a855f7, #f43f5e);
  --grad-subtle: linear-gradient(135deg, rgba(6,182,212,0.15), rgba(168,85,247,0.15), rgba(244,63,94,0.15));
  --font: 'Inter', -apple-system, sans-serif;
  --display: 'Syne', 'Inter', sans-serif;
  --mono: 'JetBrains Mono', monospace;
  --r: 12px;
  --r-sm: 8px;
  color-scheme: dark;
}

/* Font fallback size-adjust to reduce CLS */
@font-face {
  font-family: 'Inter';
  src: local('Inter');
  font-display: swap;
  size-adjust: 100%;
  ascent-override: 90%;
  descent-override: 22%;
  line-gap-override: 0%;
}
@font-face {
  font-family: 'Syne';
  src: local('Syne');
  font-display: swap;
  size-adjust: 105%;
  ascent-override: 92%;
  descent-override: 24%;
}
@font-face {
  font-family: 'JetBrains Mono';
  src: local('JetBrains Mono');
  font-display: swap;
  size-adjust: 102%;
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  background:var(--bg);color:var(--text);
  font-family:var(--font);font-size:14px;line-height:1.5;
  min-height:100vh;-webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
a{text-decoration:none;color:inherit}

/* ── SKIP LINK ────────────────────────────── */
.skip-link{
  position:absolute;top:-100%;left:16px;
  background:var(--accent);color:#fff;
  padding:8px 16px;border-radius:var(--r-sm);
  z-index:9999;font-weight:600;font-size:14px;
  transition:top .2s;
}
.skip-link:focus{top:16px}

/* ── FOCUS VISIBLE ────────────────────────── */
:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:var(--r-sm)}
:focus{scroll-margin-top:72px;scroll-margin-bottom:32px}
:target{scroll-margin-top:72px}

/* ── BACKGROUND EFFECTS ──────────────────── */
body::before {
  content:'';
  position:fixed;top:0;left:0;right:0;bottom:0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(168,85,247,0.07) 0%, transparent 50%),
    radial-gradient(ellipse 50% 40% at 85% 50%, rgba(6,182,212,0.05) 0%, transparent 50%),
    radial-gradient(ellipse 50% 40% at 15% 70%, rgba(244,63,94,0.04) 0%, transparent 50%);
  pointer-events:none;z-index:0;
}

/* Dot grid pattern */
body::after {
  content:'';
  position:fixed;top:0;left:0;right:0;bottom:0;
  background-image:radial-gradient(rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size:24px 24px;
  pointer-events:none;z-index:0;
}

/* Film grain overlay */
.grain{
  position:fixed;inset:0;
  pointer-events:none;z-index:0;
  opacity:0.35;
  background-image:url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
}

/* ── HEADER ─────────────────────────────── */
.site-header{
  position:sticky;top:0;z-index:50;
  background:rgba(6,8,13,0.85);
  backdrop-filter:blur(16px) saturate(180%);
  border-bottom:1px solid var(--border);
}
.header-inner{
  max-width:960px;margin:0 auto;padding:0 24px;
  height:56px;display:flex;align-items:center;justify-content:center;
}
.logo{
  display:flex;align-items:center;gap:10px;
  font-weight:700;font-size:17px;letter-spacing:-0.03em;color:#fff;
}
.logo-icon{
  width:28px;height:28px;flex-shrink:0;
  border-radius:7px;
}
.logo-text{
  background:linear-gradient(135deg, var(--cyan), var(--accent));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
  background-clip:text;font-weight:800;
}

/* ── HERO ──────────────────────────────── */
.hero {
  position:relative;
  text-align:center;
  padding:56px 24px 40px;
  overflow:hidden;
}
.hero::before {
  content:'';
  position:absolute;top:-120px;left:50%;transform:translateX(-50%);
  width:700px;height:400px;
  background:
    radial-gradient(ellipse 40% 60% at 30% 50%, rgba(6,182,212,0.1) 0%, transparent 70%),
    radial-gradient(ellipse 40% 60% at 50% 40%, rgba(168,85,247,0.1) 0%, transparent 70%),
    radial-gradient(ellipse 40% 60% at 70% 50%, rgba(244,63,94,0.08) 0%, transparent 70%);
  pointer-events:none;
  animation:heroPulse 6s ease-in-out infinite alternate;
}
@keyframes heroPulse {
  from { opacity:0.6;transform:translateX(-50%) scale(1) }
  to { opacity:1;transform:translateX(-50%) scale(1.1) }
}

.hero-badge {
  display:inline-flex;align-items:center;gap:6px;
  padding:5px 14px;
  border:1px solid rgba(168,85,247,0.25);
  border-radius:100px;
  background:rgba(168,85,247,0.06);
  font-size:11px;font-weight:600;letter-spacing:0.06em;
  color:var(--accent);text-transform:uppercase;
  margin-bottom:20px;
  animation:fadeDown 0.5s ease-out both;
}
.hero-badge .pulse-dot {
  width:6px;height:6px;border-radius:50%;
  background:var(--green);
  animation:pulseDot 2s ease-in-out infinite;
}
@keyframes pulseDot {
  0%,100% { opacity:1;transform:scale(1) }
  50% { opacity:0.5;transform:scale(0.7) }
}
@keyframes fadeDown {
  from { opacity:0;transform:translateY(-10px) }
  to { opacity:1;transform:translateY(0) }
}

.hero h1 {
  font-family:var(--display);
  font-size:clamp(28px, 5vw, 42px);
  font-weight:800;letter-spacing:-0.04em;
  color:#fff;line-height:1.15;
  margin-bottom:12px;
  animation:fadeDown 0.6s 0.1s ease-out both;
}
.hero h1 .gradient-text {
  background:linear-gradient(135deg, #06b6d4 0%, #a855f7 40%, #f43f5e 80%, #06b6d4 100%);
  background-size:300% auto;
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
  animation:shimmer 5s linear infinite;
}
@keyframes shimmer {
  to { background-position:300% center }
}

.hero p {
  font-size:15px;color:var(--text2);
  max-width:520px;margin:0 auto;line-height:1.6;
  animation:fadeDown 0.6s 0.2s ease-out both;
}

/* ── MAIN ───────────────────────────────── */
.main{max-width:960px;margin:0 auto;padding:0 24px 80px;position:relative;z-index:1}

/* ── INPUT PANEL ─────────────────────────── */
.input-panel{
  background:rgba(12,16,24,0.7);
  backdrop-filter:blur(12px);
  border:1px solid var(--border);
  border-radius:var(--r);
  padding:24px;
  margin-bottom:28px;
  animation:fadeUp 0.5s ease-out both;
}

@keyframes fadeUp{
  from{opacity:0;transform:translateY(16px)}
  to{opacity:1;transform:translateY(0)}
}

.input-row{
  display:flex;gap:12px;align-items:end;
  flex-wrap:wrap;
}

.input-group{
  flex:1;min-width:200px;
  display:flex;flex-direction:column;gap:6px;
}
.input-group--narrow{max-width:140px}
.input-group--mb{margin-bottom:12px}

.input-label{
  font-size:11px;font-weight:600;
  text-transform:uppercase;letter-spacing:0.08em;
  color:var(--text3);
}

.input-field{
  display:flex;align-items:center;gap:10px;
  background:rgba(255,255,255,0.03);
  border:1px solid var(--border2);
  border-radius:var(--r-sm);
  padding:11px 14px;
  transition:border-color 0.2s, box-shadow 0.2s;
}
.input-field:focus-within {
  border-color:rgba(168,85,247,0.4);
  box-shadow:0 0 0 3px rgba(168,85,247,0.08);
}
.input-field svg{color:var(--text3);flex-shrink:0;width:18px;height:18px}
.input-field input{
  flex:1;background:none;border:none;outline:none;
  color:var(--text);font-family:var(--mono);font-size:14px;
  letter-spacing:0.02em;
}
.input-field input::placeholder{color:var(--text3);font-family:var(--font)}

/* Remove number input spinners */
.input-field input[type="number"]::-webkit-inner-spin-button,
.input-field input[type="number"]::-webkit-outer-spin-button{-webkit-appearance:none;margin:0}
.input-field input[type="number"]{-moz-appearance:textfield}

.btn-calculate{
  display:inline-flex;align-items:center;gap:8px;
  padding:11px 24px;
  border-radius:var(--r-sm);
  border:none;
  background:var(--accent);color:#fff;
  font-family:var(--font);font-size:13px;font-weight:600;
  cursor:pointer;transition:all 0.2s ease;
  white-space:nowrap;
  letter-spacing:0.02em;
}
.btn-calculate:hover{
  background:var(--accent-h);
  box-shadow:0 0 24px rgba(168,85,247,0.3);
  transform:translateY(-1px);
}
.btn-calculate:active{transform:translateY(0)}
.btn-calculate svg{width:16px;height:16px}

.error-msg{
  margin-top:10px;
  font-size:12px;color:var(--rose);
  font-weight:500;
  display:none;
}
.error-msg.visible{display:block}

/* ── MODE TABS ────────────────────────── */
.mode-tabs{
  display:flex;gap:4px;
  margin-bottom:16px;
}
.mode-tab{
  padding:7px 16px;
  min-height:36px;
  border-radius:100px;
  border:1px solid var(--border2);
  background:rgba(255,255,255,0.02);
  color:var(--text2);
  font-family:var(--font);font-size:12px;font-weight:500;
  cursor:pointer;transition:all 0.2s ease;
}
.mode-tab:hover{border-color:rgba(168,85,247,0.3);color:var(--accent)}
.mode-tab.active{
  background:var(--accent);border-color:var(--accent);color:#fff;
  box-shadow:0 0 16px rgba(168,85,247,0.2);
}

/* ── RESULTS ─────────────────────────────── */
.results{display:none}
.results.visible{display:block}

.results-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(280px,1fr));
  gap:16px;
  margin-bottom:24px;
}

.result-card{
  background:rgba(12,16,24,0.7);
  backdrop-filter:blur(8px);
  border:1px solid var(--border);
  border-radius:var(--r);
  padding:18px 20px;
  transition:all 0.3s cubic-bezier(0.4,0,0.2,1);
  animation:fadeUp 0.4s both ease-out;
  position:relative;
}
.result-card::before {
  content:'';
  position:absolute;inset:-1px;
  border-radius:var(--r);
  padding:1px;
  background:linear-gradient(135deg, transparent 0%, transparent 100%);
  -webkit-mask:linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  mask:linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite:xor;
  mask-composite:exclude;
  transition:background 0.3s ease;
  pointer-events:none;z-index:1;
}
.result-card:hover{
  border-color:rgba(168,85,247,0.15);
  box-shadow:
    0 8px 40px rgba(0,0,0,0.4),
    0 0 30px rgba(168,85,247,0.05);
  transform:translateY(-2px);
}
.result-card:hover::before {
  background:linear-gradient(135deg, rgba(6,182,212,0.3) 0%, rgba(168,85,247,0.2) 40%, rgba(244,63,94,0.2) 100%);
}

.result-card-label{
  font-size:10px;font-weight:600;
  text-transform:uppercase;letter-spacing:0.08em;
  color:var(--text3);margin-bottom:6px;
}
.result-card-value{
  font-family:var(--mono);
  font-size:15px;font-weight:600;
  color:#fff;word-break:break-all;
  letter-spacing:0.01em;
}
.result-card-value.small{font-size:12px;color:var(--text2)}

/* color accents for specific cards */
.result-card[data-type="network"] .result-card-value{color:var(--cyan)}
.result-card[data-type="broadcast"] .result-card-value{color:var(--rose)}
.result-card[data-type="range"] .result-card-value{color:var(--green)}
.result-card[data-type="hosts"] .result-card-value{color:var(--amber)}
.result-card[data-type="class"] .result-card-value{color:var(--accent)}

/* staggered card animations */
.result-card:nth-child(1){animation-delay:0s}
.result-card:nth-child(2){animation-delay:0.04s}
.result-card:nth-child(3){animation-delay:0.08s}
.result-card:nth-child(4){animation-delay:0.12s}
.result-card:nth-child(5){animation-delay:0.16s}
.result-card:nth-child(6){animation-delay:0.2s}
.result-card:nth-child(7){animation-delay:0.24s}
.result-card:nth-child(8){animation-delay:0.28s}
.result-card:nth-child(9){animation-delay:0.32s}
.result-card:nth-child(10){animation-delay:0.36s}

/* ── FULL-WIDTH RESULT SECTIONS ───────── */
.result-section{
  background:rgba(12,16,24,0.7);
  backdrop-filter:blur(8px);
  border:1px solid var(--border);
  border-radius:var(--r);
  padding:20px 24px;
  margin-bottom:16px;
  animation:fadeUp 0.4s 0.35s both ease-out;
}
.result-section-title{
  font-size:13px;font-weight:700;color:#fff;
  margin-bottom:14px;
  display:flex;align-items:center;gap:8px;
}
.result-section-title svg{width:16px;height:16px;color:var(--accent)}

.binary-display{
  font-family:var(--mono);
  font-size:12px;
  line-height:2;
  color:var(--text2);
}
.binary-display .highlight{color:var(--cyan);font-weight:600}
.binary-display .dim{color:var(--text3)}

.subnet-list{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(240px,1fr));
  gap:8px;
}
.subnet-list--mt{margin-top:16px}
.subnet-item{
  font-family:var(--mono);
  font-size:12px;
  padding:8px 12px;
  border-radius:var(--r-sm);
  background:rgba(255,255,255,0.02);
  border:1px solid var(--border);
  color:var(--text2);
  transition:all 0.2s;
}
.subnet-item:hover{
  border-color:rgba(6,182,212,0.3);
  color:var(--cyan);
}

/* ── VISUAL SUBNET MAP ────────────────────── */
.subnet-map{
  display:flex;
  border-radius:var(--r-sm);
  overflow:hidden;
  height:32px;
  margin-top:12px;
  border:1px solid var(--border);
}
.subnet-map-seg{
  position:relative;
  display:flex;align-items:center;justify-content:center;
  font-family:var(--mono);font-size:9px;
  color:rgba(255,255,255,0.8);font-weight:600;
  transition:all 0.2s;
  cursor:default;
  min-width:2px;
}
.subnet-map-seg:hover{filter:brightness(1.3)}

.map-colors-0{background:rgba(6,182,212,0.5)}
.map-colors-1{background:rgba(168,85,247,0.5)}
.map-colors-2{background:rgba(244,63,94,0.5)}
.map-colors-3{background:rgba(245,158,11,0.5)}
.map-colors-4{background:rgba(16,185,129,0.5)}
.map-colors-5{background:rgba(59,130,246,0.5)}
.map-colors-6{background:rgba(236,72,153,0.5)}
.map-colors-7{background:rgba(139,92,246,0.5)}

/* ── IPv6 SECTION ────────────────────────── */
.ipv6-expanded{
  font-family:var(--mono);
  font-size:13px;
  color:var(--cyan);
  word-break:break-all;
  margin-bottom:4px;
}
.ipv6-compressed{
  font-family:var(--mono);
  font-size:12px;
  color:var(--text3);
}

/* ── FOOTER ─────────────────────────────── */
.site-footer{
  border-top:1px solid var(--border);
  position:relative;z-index:1;
}

.footer-ecosystem{
  max-width:960px;margin:0 auto;
  padding:28px 24px 20px;
  text-align:center;
}
.footer-ecosystem-title{
  display:block;
  font-size:10px;font-weight:600;
  text-transform:uppercase;letter-spacing:0.1em;
  color:var(--text3);margin-bottom:14px;
}
.footer-ecosystem-links{
  display:flex;justify-content:center;gap:8px;
  flex-wrap:wrap;
}
.footer-eco-link{
  display:inline-flex;align-items:center;gap:6px;
  padding:6px 16px;
  min-height:32px;
  border-radius:100px;
  border:1px solid var(--border2);
  background:rgba(255,255,255,0.02);
  font-size:12px;font-weight:500;
  color:var(--text2);
  transition:all 0.2s ease;
}
.footer-eco-link:hover{
  border-color:rgba(168,85,247,0.35);
  color:var(--accent);
  background:rgba(168,85,247,0.04);
  box-shadow:0 0 12px rgba(168,85,247,0.08);
}

.footer-inner{
  max-width:960px;margin:0 auto;
  padding:16px 24px 24px;
  display:flex;justify-content:center;align-items:center;
  font-size:12px;color:var(--text3);
}

/* ── VISUALLY HIDDEN (a11y) ────────────── */
.sr-only{
  position:absolute;width:1px;height:1px;
  padding:0;margin:-1px;overflow:hidden;
  clip:rect(0,0,0,0);white-space:nowrap;border:0;
}

/* ── TOOLTIP ─────────────────────────────── */
[data-tooltip]{position:relative}
[data-tooltip]:hover::after{
  content:attr(data-tooltip);
  position:absolute;bottom:calc(100% + 8px);left:50%;
  transform:translateX(-50%);
  padding:5px 10px;border-radius:6px;
  background:var(--surface2);border:1px solid var(--border2);
  font-size:11px;color:var(--text);white-space:nowrap;
  z-index:10;pointer-events:none;
  animation:fadeDown 0.15s ease-out;
}

/* ── 404 PAGE ────────────────────────────── */
.page-404{text-align:center;padding-top:120px}
.page-404-code{
  font-family:var(--display);
  font-size:64px;font-weight:800;margin-bottom:8px;
  background:var(--grad);
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
  background-clip:text;
}
.page-404-msg{color:var(--text2);margin-bottom:32px}
.page-404 .btn-calculate{display:inline-flex;text-decoration:none}

/* ── REDUCED MOTION ──────────────────────── */
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:0.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:0.01ms !important;
    scroll-behavior:auto !important;
  }
}

/* ── RESPONSIVE ──────────────────────────── */
@media(max-width:640px){
  .header-inner{padding:0 16px}
  .hero{padding:40px 16px 28px}
  .main{padding:0 16px 60px}
  .input-row{flex-direction:column}
  .input-group{min-width:auto}
  .results-grid{grid-template-columns:1fr}
  .split-controls{flex-direction:column}
  .split-input{width:100%}
  .footer-inner{flex-direction:column;gap:8px;text-align:center}
  .subnet-list{grid-template-columns:1fr}
}

/* ── PRINT ───────────────────────────────── */
@media print{
  body::before,body::after,.grain,.site-header,.hero-badge,.hero::before{display:none}
  body{background:#fff;color:#000}
  .result-card{border:1px solid #ccc;background:#f9f9f9}
  .result-card-value{color:#000!important}
}