/* ============================================================
   VLSM Calculator — style.css
   Networking Dark Theme
   ============================================================ */

/* ── Design Tokens ── */
:root {
  --bg:        #0a0e1a;
  --bg2:       #0f1528;
  --bg3:       #141c35;
  --bg4:       #1a2240;
  --border:    #1e2d4f;
  --border2:   #253660;
  --blue:      #2563eb;
  --blue-h:    #3b82f6;
  --blue-dim:  #1e3a5f;
  --green:     #10b981;
  --green-h:   #34d399;
  --orange:    #f59e0b;
  --purple:    #7c3aed;
  --red:       #ef4444;
  --text:      #e2e8f0;
  --text2:     #94a3b8;
  --text3:     #475569;
  --white:     #f8fafc;
  --mono:      'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
  --sans:      'Inter', system-ui, sans-serif;
  --r:         6px;
  --r-lg:      10px;
  --shadow:    0 4px 24px rgba(0,0,0,0.5);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.4);
  --trans:     0.15s ease;
  --glow-blue: 0 0 20px rgba(37,99,235,0.25);
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  font-size: 14px;
  line-height: 1.6;
  background-image:
    radial-gradient(ellipse at 20% 0%, rgba(37,99,235,0.06) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 100%, rgba(16,185,129,0.04) 0%, transparent 60%);
}

/* ── Topbar ── */
.topbar {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 0 28px;
  height: 58px;
  display: flex;
  align-items: center;
  gap: 14px;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}
.topbar-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}
.topbar-logo-icon {
  width: 32px;
  height: 32px;
  background: var(--blue);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  box-shadow: var(--glow-blue);
}
.topbar-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--white);
  letter-spacing: -0.3px;
}
.topbar-sep { width: 1px; height: 22px; background: var(--border); margin: 0 6px; }
.topbar-sub { font-size: 11px; color: var(--text3); letter-spacing: 0.3px; }
.topbar-right { margin-left: auto; display: flex; align-items: center; gap: 8px; }
.status-badge {
  display: flex;
  align-items: center;
  gap: 5px;
  background: rgba(16,185,129,0.1);
  border: 1px solid rgba(16,185,129,0.25);
  border-radius: 20px;
  padding: 3px 10px;
  font-size: 10px;
  font-weight: 600;
  color: var(--green-h);
  letter-spacing: 0.5px;
}
.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--green-h);
  box-shadow: 0 0 6px var(--green-h);
  animation: pulse 2s ease infinite;
}
@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:0.4} }

/* ── Nav Tabs ── */
.nav-tabs {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  display: flex;
  padding: 0 28px;
  gap: 2px;
}
.nav-tab {
  padding: 10px 18px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text3);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all var(--trans);
  letter-spacing: 0.3px;
  text-transform: uppercase;
  background: none;
  border-left: none;
  border-right: none;
  border-top: none;
  display: flex;
  align-items: center;
  gap: 6px;
}
.nav-tab:hover { color: var(--text2); }
.nav-tab.active { color: var(--blue-h); border-bottom-color: var(--blue); }

/* ── Layout ── */
.main {
  max-width: 1280px;
  margin: 0 auto;
  padding: 28px 24px 80px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.section { display: none; }
.section.active { display: block; }

/* ── Cards ── */
.card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.card-header {
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--bg3);
  display: flex;
  align-items: center;
  gap: 10px;
}
.card-header-icon {
  width: 30px;
  height: 30px;
  border-radius: 7px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  flex-shrink: 0;
}
.icon-blue   { background: rgba(37,99,235,0.15); color: var(--blue-h); }
.icon-green  { background: rgba(16,185,129,0.15); color: var(--green-h); }
.icon-orange { background: rgba(245,158,11,0.15); color: var(--orange); }
.icon-purple { background: rgba(124,58,237,0.15); color: #a78bfa; }
.card-header h2 { font-size: 13px; font-weight: 600; color: var(--white); }
.card-header p  { font-size: 11px; color: var(--text3); margin-top: 1px; }
.card-body { padding: 20px; }

/* ── Section Headers ── */
.section-title {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text3);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.section-title::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

/* ── Form Elements ── */
.form-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: flex-end;
  margin-bottom: 14px;
}
.field { display: flex; flex-direction: column; gap: 5px; }
.field-label {
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text3);
}
input[type="text"],
input[type="number"],
select {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--r);
  color: var(--text);
  font-family: var(--mono);
  font-size: 13px;
  padding: 8px 12px;
  outline: none;
  transition: border var(--trans), box-shadow var(--trans);
}
input[type="text"]:focus,
input[type="number"]:focus,
select:focus {
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.15);
}
input::placeholder { color: var(--text3); }
select { cursor: pointer; }
select option { background: var(--bg2); }

/* ── Mode Tabs ── */
.mode-tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 18px;
}
.mode-tab {
  padding: 8px 20px;
  border-radius: var(--r);
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text3);
  font-family: var(--sans);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--trans);
  letter-spacing: 0.3px;
}
.mode-tab:hover { border-color: var(--blue); color: var(--blue-h); }
.mode-tab.active {
  background: var(--blue);
  border-color: var(--blue);
  color: #fff;
  box-shadow: var(--glow-blue);
}

/* ── Buttons ── */
.btn-row { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 14px; }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  border: none;
  border-radius: var(--r);
  font-family: var(--sans);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--trans);
  letter-spacing: 0.2px;
  white-space: nowrap;
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--blue); color: #fff; }
.btn-primary:hover { background: var(--blue-h); box-shadow: var(--glow-blue); }
.btn-success { background: var(--green); color: #fff; }
.btn-success:hover { background: var(--green-h); }
.btn-ghost { background: var(--bg3); color: var(--text2); border: 1px solid var(--border); }
.btn-ghost:hover { border-color: var(--text3); color: var(--text); }
.btn-danger-outline { background: transparent; border: 1px solid rgba(239,68,68,0.3); color: #f87171; }
.btn-danger-outline:hover { background: rgba(239,68,68,0.1); border-color: var(--red); }
.btn-icon-danger {
  background: transparent;
  border: 1px solid rgba(239,68,68,0.25);
  color: #f87171;
  padding: 5px 9px;
  border-radius: var(--r);
  font-size: 12px;
  cursor: pointer;
  transition: all var(--trans);
}
.btn-icon-danger:hover { background: rgba(239,68,68,0.1); border-color: var(--red); }

/* ── VLSM Entry List ── */
.vlsm-entry {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--r);
  margin-bottom: 6px;
}
.vlsm-entry:last-child { margin-bottom: 0; }
.vlsm-label {
  font-size: 11px;
  color: var(--blue-h);
  font-family: var(--mono);
  font-weight: 600;
  min-width: 65px;
}
.vlsm-entry input { flex: 1; max-width: 180px; }

/* ── Result Table ── */
.table-info-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 18px;
  background: var(--bg3);
  border-bottom: 1px solid var(--border);
  font-size: 12px;
  font-weight: 600;
  color: var(--white);
}
.next-label { color: var(--text3); font-weight: 400; margin-left: auto; }
.next-addr {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--green-h);
  background: rgba(16,185,129,0.08);
  padding: 2px 8px;
  border-radius: 4px;
  border: 1px solid rgba(16,185,129,0.2);
}

.table-wrap { overflow-x: auto; }
.subnet-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 12.5px;
  min-width: 920px;
}
.subnet-table thead tr { background: var(--bg4); }
.subnet-table th {
  padding: 10px 14px;
  text-align: left;
  font-size: 10px;
  font-weight: 700;
  color: var(--text3);
  text-transform: uppercase;
  letter-spacing: 0.8px;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
.subnet-table td {
  padding: 9px 14px;
  border-bottom: 1px solid rgba(30,45,79,0.5);
  white-space: nowrap;
  transition: background var(--trans);
}
.subnet-table tbody tr:hover td { background: rgba(37,99,235,0.06); }
.subnet-table tbody tr:last-child td { border-bottom: none; }
.col-no      { color: var(--text3); font-family: var(--mono); font-size: 11px; }
.col-cidr    { font-family: var(--mono); font-weight: 700; color: var(--green-h); }
.col-network { font-family: var(--mono); font-weight: 600; color: var(--blue-h); }
.col-octet   { color: var(--text3); font-size: 11px; }
.col-inc     { font-family: var(--mono); color: var(--orange); }
.mono  { font-family: var(--mono); }
.muted { color: var(--text3); }
.green { color: var(--green-h); }
.blue  { color: var(--blue-h); }
.bold  { font-weight: 700; }

/* ── Table Actions ── */
.table-actions {
  padding: 12px 18px;
  border-top: 1px solid var(--border);
  background: var(--bg3);
  display: flex;
  gap: 8px;
}

/* ── Error ── */
.error-msg {
  color: #f87171;
  font-size: 12px;
  margin-top: 8px;
  min-height: 16px;
}

/* ── CLI Section ── */
.cli-locked {
  padding: 32px;
  text-align: center;
  color: var(--text3);
}
.cli-locked-icon { font-size: 32px; margin-bottom: 12px; opacity: 0.4; }
.cli-locked h3   { font-size: 14px; color: var(--text2); margin-bottom: 6px; }
.cli-locked p    { font-size: 12px; }

/* Topology buttons */
.topo-row {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
}
.topo-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: var(--r);
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text3);
  font-family: var(--sans);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--trans);
}
.topo-btn:hover { border-color: var(--blue); color: var(--blue-h); }
.topo-btn.active {
  background: rgba(37,99,235,0.1);
  border-color: var(--blue);
  color: var(--blue-h);
  box-shadow: 0 0 0 1px rgba(37,99,235,0.2);
}

/* Protocol buttons */
.proto-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-bottom: 14px;
}
.proto-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
  padding: 12px 8px;
  border-radius: var(--r);
  border: 1px solid var(--border);
  background: var(--bg);
  cursor: pointer;
  transition: all var(--trans);
  position: relative;
  overflow: hidden;
}
.proto-btn::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 2px;
  opacity: 0;
  transition: opacity var(--trans);
}
.proto-btn:hover { transform: translateY(-2px); }
.proto-btn.active { transform: translateY(-2px); }
.proto-btn-icon { font-size: 18px; }
.proto-btn-label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.8px;
  text-transform: uppercase;
}

.pb-static { border-color: #1e3a5f; }
.pb-static:hover, .pb-static.active { background: rgba(37,99,235,0.08); border-color: var(--blue); }
.pb-static .proto-btn-label { color: var(--blue-h); }
.pb-static::after { background: var(--blue); }
.pb-static:hover::after, .pb-static.active::after { opacity: 1; }

.pb-rip { border-color: #14532d; }
.pb-rip:hover, .pb-rip.active { background: rgba(16,185,129,0.08); border-color: var(--green); }
.pb-rip .proto-btn-label { color: var(--green-h); }
.pb-rip::after { background: var(--green); }
.pb-rip:hover::after, .pb-rip.active::after { opacity: 1; }

.pb-eigrp { border-color: #451a03; }
.pb-eigrp:hover, .pb-eigrp.active { background: rgba(245,158,11,0.08); border-color: var(--orange); }
.pb-eigrp .proto-btn-label { color: var(--orange); }
.pb-eigrp::after { background: var(--orange); }
.pb-eigrp:hover::after, .pb-eigrp.active::after { opacity: 1; }

.pb-ospf { border-color: #3b1f6b; }
.pb-ospf:hover, .pb-ospf.active { background: rgba(124,58,237,0.08); border-color: var(--purple); }
.pb-ospf .proto-btn-label { color: #a78bfa; }
.pb-ospf::after { background: var(--purple); }
.pb-ospf:hover::after, .pb-ospf.active::after { opacity: 1; }

/* Extra protocol fields */
.proto-extra-field {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
  font-size: 12px;
  color: var(--text2);
}
.proto-extra-field input { width: 100px; }

/* Router grid */
.router-controls {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
  align-items: center;
}
.router-count {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--blue-h);
  background: var(--blue-dim);
  padding: 4px 10px;
  border-radius: 4px;
  margin-left: auto;
}
.router-assign-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 10px;
  margin-bottom: 16px;
}
.router-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--r);
  overflow: hidden;
  transition: border var(--trans);
}
.router-card:hover { border-color: var(--border2); }
.router-card-title {
  padding: 9px 14px;
  background: var(--bg3);
  border-bottom: 1px solid var(--border);
  font-size: 12px;
  font-weight: 700;
  color: var(--blue-h);
  display: flex;
  align-items: center;
  gap: 6px;
}
.router-icon { font-size: 14px; }
.net-check-list { padding: 10px 14px; display: flex; flex-direction: column; gap: 6px; }
.net-check {
  display: flex;
  align-items: center;
  gap: 7px;
  font-size: 11px;
  color: var(--text2);
  cursor: pointer;
  font-family: var(--mono);
}
.net-check input { accent-color: var(--blue); width: 13px; height: 13px; }
.net-check:hover { color: var(--text); }

/* Serial links */
.serial-hint {
  font-size: 11px;
  color: var(--text3);
  margin-bottom: 10px;
  padding: 8px 12px;
  background: var(--bg);
  border-radius: var(--r);
  border: 1px solid var(--border);
}
.serial-entry {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--r);
  margin-bottom: 6px;
}
.serial-entry:last-child { margin-bottom: 0; }
.serial-label {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--blue-h);
  font-weight: 600;
  min-width: 90px;
}
.serial-arrow { color: var(--text3); font-size: 12px; }
.serial-entry select { flex: 1; }

/* ── CLI Output ── */
.router-output {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  overflow: hidden;
  margin-bottom: 14px;
  box-shadow: var(--shadow-sm);
}
.router-output-header {
  padding: 11px 18px;
  background: var(--bg3);
  border-bottom: 1px solid var(--border);
  font-size: 13px;
  font-weight: 700;
  color: var(--blue-h);
  display: flex;
  align-items: center;
  gap: 8px;
}
.router-output-icon { font-size: 16px; }
.tab-bar {
  display: flex;
  border-bottom: 1px solid var(--border);
  background: var(--bg2);
}
.tab-btn {
  padding: 9px 18px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text3);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: all var(--trans);
}
.tab-btn:hover { color: var(--text2); }
.tab-btn.active { color: var(--green-h); border-bottom-color: var(--green); }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* Terminal / Code block */
.code-block {
  background: #050810;
  color: #4ade80;
  font-family: var(--mono);
  font-size: 12.5px;
  padding: 16px 20px;
  white-space: pre;
  overflow-x: auto;
  line-height: 1.65;
  position: relative;
  border-top: 1px solid #0d1f0d;
}
.copy-btn {
  position: absolute;
  top: 10px;
  right: 14px;
  background: rgba(74,222,128,0.08);
  border: 1px solid rgba(74,222,128,0.2);
  color: #4ade80;
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 4px;
  cursor: pointer;
  letter-spacing: 1px;
  transition: all var(--trans);
}
.copy-btn:hover { background: rgba(74,222,128,0.15); border-color: #4ade80; }
.copy-btn.copied { background: rgba(74,222,128,0.2); color: #86efac; }

/* ── Cheat Sheet ── */
.cheat-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 12px;
}
.cheat-table th {
  padding: 8px 12px;
  text-align: left;
  font-size: 10px;
  font-weight: 700;
  color: var(--text3);
  text-transform: uppercase;
  letter-spacing: 0.8px;
  border-bottom: 1px solid var(--border);
  background: var(--bg3);
}
.cheat-table td {
  padding: 7px 12px;
  border-bottom: 1px solid rgba(30,45,79,0.4);
  font-family: var(--mono);
  font-size: 12px;
}
.cheat-table tbody tr:hover td { background: rgba(37,99,235,0.05); }
.cheat-table tbody tr:last-child td { border-bottom: none; }

/* ── Utility ── */
.hidden { display: none !important; }
.divider { border: none; border-top: 1px solid var(--border); margin: 16px 0; }

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--border2); }

/* ── Responsive ── */
@media (max-width: 768px) {
  .main { padding: 16px 14px 60px; }
  .topbar { padding: 0 16px; }
  .proto-row { grid-template-columns: repeat(2, 1fr); }
  .router-assign-grid { grid-template-columns: 1fr; }
  .topbar-sub { display: none; }
}