:root {
  --primary: #1d4ed8;
  --primary-light: #eff6ff;
  --success: #059669;
  --warning: #b45309;
  --danger: #dc2626;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --border: #e2e8f0;
  --card-bg: #fff;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07);
  /* Path colors */
  --clr-fwd: #2563eb;
  --clr-rev: #16a34a;
  --clr-dead: #dc2626;
  --clr-loop: #f97316;
  --clr-added: #d97706;
  --clr-unused: #cbd5e1;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; -webkit-tap-highlight-color: transparent; }
html, body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif; background: #f8fafc; color: var(--text-primary); min-height: 100vh; }
a { color: var(--primary); text-decoration: none; }
code { font-family: monospace; background: #f1f5f9; padding: 1px 5px; border-radius: 4px; font-size: 0.85em; color: var(--primary); }

/* NAV */
.top-nav { background: rgba(255,255,255,0.95); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid var(--border); padding: 0 20px; position: sticky; top: 0; z-index: 300; }
.top-nav-inner { height: 52px; max-width: 1200px; margin: 0 auto; display: flex; align-items: center; gap: 12px; }
.nav-back { font-size: 0.82rem; font-weight: 600; color: var(--text-secondary); padding: 6px 12px; border: 1px solid var(--border); border-radius: 20px; white-space: nowrap; transition: all 0.15s; }
.nav-back:hover { color: var(--primary); border-color: var(--primary); }
.nav-title { font-size: 0.9rem; font-weight: 800; color: var(--text-primary); flex: 1; }

/* HERO */
.tool-hero { background: linear-gradient(135deg, #0f2d6b 0%, #1d4ed8 55%, #3b82f6 100%); color: #fff; padding: 28px 20px 24px; text-align: center; }
.tool-hero h1 { font-size: 1.45rem; font-weight: 900; margin-bottom: 6px; }
.tool-hero p { font-size: 0.85rem; opacity: 0.88; }
.hero-chips { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; margin-top: 14px; }
.hero-chip { background: rgba(255,255,255,0.15); border: 1px solid rgba(255,255,255,0.3); border-radius: 20px; padding: 4px 12px; font-size: 0.75rem; font-weight: 600; }

/* MODE TABS */
.mode-tabs-wrap { background: var(--card-bg); border-bottom: 1px solid var(--border); }
.mode-tabs { display: flex; max-width: 1200px; margin: 0 auto; }
.mode-tab { flex: 1; display: flex; align-items: center; justify-content: center; gap: 8px; padding: 14px 16px; border: none; border-bottom: 3px solid transparent; background: none; cursor: pointer; font-size: 0.88rem; font-weight: 700; color: var(--text-muted); transition: all 0.15s; }
.mode-tab:hover { color: var(--text-secondary); background: #f8fafc; }
.mode-tab.active { color: var(--primary); border-bottom-color: var(--primary); background: var(--primary-light); }
.mode-tab-icon { font-size: 1.2rem; }

/* TOOL WRAP */
.tool-wrap { max-width: 1200px; margin: 0 auto; padding: 14px 12px 60px; display: flex; flex-direction: column; gap: 14px; }

/* STATS */
.stats-row { display: flex; gap: 10px; }
.stat-card { flex: 1; background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 12px; text-align: center; box-shadow: var(--shadow); }
.stat-num { font-size: 1.5rem; font-weight: 900; color: var(--primary); }
.stat-label { font-size: 0.72rem; color: var(--text-muted); font-weight: 600; margin-top: 2px; }

/* TASK CARD */
.task-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow); }
.task-badge { display: inline-block; font-size: 0.72rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.05em; color: var(--primary); background: var(--primary-light); padding: 3px 10px; border-radius: 20px; margin-bottom: 8px; }
.task-title { font-size: 1rem; font-weight: 900; color: var(--text-primary); margin-bottom: 6px; }
.task-desc { font-size: 0.82rem; line-height: 1.75; color: var(--text-secondary); }

/* MAIN LAYOUT */
.main-layout { display: grid; grid-template-columns: 1fr; gap: 14px; }
@media (min-width: 900px) { .main-layout { grid-template-columns: 3fr 2fr; } }

/* TOPO PANEL */
.topo-panel { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; display: flex; flex-direction: column; }
.topo-panel-header { padding: 10px 14px; background: #f8fafc; border-bottom: 1px solid var(--border); display: flex; align-items: center; justify-content: space-between; gap: 8px; flex-wrap: wrap; }
.topo-panel-title { font-size: 0.85rem; font-weight: 800; }
.svg-wrap { width: 100%; background: #f8fafc; overflow: hidden; }
#topoSvg, #labSvg { display: block; width: 100%; height: auto; cursor: default; }
.topo-hint { padding: 6px 14px; font-size: 0.72rem; color: var(--text-muted); border-top: 1px solid var(--border); background: #f8fafc; }

/* PATH LEGEND INLINE */
.path-legend-inline { display: flex; gap: 8px; align-items: center; font-size: 0.7rem; color: var(--text-muted); flex-wrap: wrap; }
.ldot { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: 2px; }
.ldot.fwd { background: var(--clr-fwd); }
.ldot.rev { background: var(--clr-rev); }
.ldot.dead { background: var(--clr-dead); }
.ldot.loop { background: var(--clr-loop); }
.ldot.added { background: var(--clr-added); }

/* CTRL PANEL */
.ctrl-panel { display: flex; flex-direction: column; gap: 12px; }
.ctrl-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px; box-shadow: var(--shadow); }
.ctrl-card-header { font-size: 0.8rem; font-weight: 800; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 10px; }

/* FORMS */
.route-form { display: flex; flex-direction: column; gap: 8px; }
.form-row { display: flex; flex-direction: column; gap: 3px; }
.form-row label { font-size: 0.75rem; font-weight: 700; color: var(--text-muted); }
.full-input, .full-select { width: 100%; padding: 8px 10px; border: 1.5px solid var(--border); border-radius: var(--radius-sm); font-size: 0.82rem; color: var(--text-primary); background: var(--card-bg); appearance: none; }
.full-input:focus, .full-select:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 2px rgba(29,78,216,0.1); }
.input-with-datalist { position: relative; }

/* BUTTONS */
.btn-primary { width: 100%; padding: 10px; border-radius: var(--radius-sm); border: none; background: var(--primary); color: #fff; font-size: 0.85rem; font-weight: 700; cursor: pointer; transition: background 0.15s; }
.btn-primary:hover { background: #1e40af; }
.icon-btn { padding: 6px 10px; border-radius: 6px; border: 1px solid var(--border); background: var(--card-bg); cursor: pointer; font-size: 1rem; transition: all 0.15s; }
.icon-btn:hover { border-color: var(--primary); }
.icon-btn.danger:hover { border-color: var(--danger); }
.badge { background: var(--primary); color: #fff; font-size: 0.7rem; padding: 1px 7px; border-radius: 20px; font-weight: 700; }

/* ROUTING TABLE */
.rtable-wrap { margin-top: 8px; }
.empty-hint { font-size: 0.78rem; color: var(--text-muted); padding: 8px 0; }
.rtable { width: 100%; border-collapse: collapse; font-size: 0.75rem; }
.rtable th { background: #f1f5f9; padding: 5px 8px; text-align: left; font-weight: 700; color: var(--text-secondary); border-bottom: 1px solid var(--border); }
.rtable td { padding: 5px 8px; border-bottom: 1px solid #f1f5f9; color: var(--text-primary); }
.rtable tr:last-child td { border-bottom: none; }
.rtable tr.connected td { color: var(--success); }
.rtable tr.static td { color: var(--primary); }
.rtable tr.default td { color: var(--warning); }
.rtable tr.user-added td { color: var(--clr-added); font-weight: 700; }
.route-tag { font-size: 0.65rem; padding: 1px 5px; border-radius: 10px; font-weight: 700; }
.route-tag.connected { background: #dcfce7; color: var(--success); }
.route-tag.static { background: var(--primary-light); color: var(--primary); }
.route-tag.default { background: #fef3c7; color: var(--warning); }
.route-tag.user { background: #fef9c3; color: #854d0e; }

/* USER ROUTES LIST */
.user-route-item { display: flex; align-items: flex-start; gap: 8px; padding: 8px 0; border-bottom: 1px solid #f1f5f9; }
.user-route-item:last-child { border-bottom: none; }
.user-route-info { flex: 1; min-width: 0; }
.user-route-device { font-size: 0.72rem; font-weight: 800; color: var(--primary); }
.user-route-route { font-size: 0.78rem; color: var(--text-primary); font-family: monospace; }
.user-route-memo { font-size: 0.7rem; color: var(--text-muted); }
.user-route-del { padding: 2px 8px; border: 1px solid var(--border); border-radius: 4px; background: none; cursor: pointer; font-size: 0.7rem; color: var(--danger); flex-shrink: 0; }
.user-route-del:hover { background: #fef2f2; border-color: var(--danger); }

/* ACTION BAR */
.action-bar { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px 14px; box-shadow: var(--shadow); }
.btn-action { padding: 9px 16px; border-radius: var(--radius-sm); border: 1.5px solid var(--border); background: var(--card-bg); color: var(--text-secondary); font-size: 0.82rem; font-weight: 700; cursor: pointer; transition: all 0.15s; white-space: nowrap; }
.btn-action:hover { border-color: var(--primary); color: var(--primary); }
.btn-action.primary { background: var(--primary); color: #fff; border-color: var(--primary); }
.btn-action.primary:hover { background: #1e40af; }
.btn-action.success { background: var(--success); color: #fff; border-color: var(--success); }
.btn-action.success:hover { background: #047857; }
.btn-action.warn { background: #f59e0b; color: #fff; border-color: #f59e0b; }
.btn-action.warn:hover { background: #d97706; }
.btn-action.danger { color: var(--danger); border-color: var(--danger); }
.btn-action.danger:hover { background: #fef2f2; }
.btn-action.muted { color: var(--text-muted); }
.action-label { font-size: 0.78rem; font-weight: 700; color: var(--text-muted); }
.action-select { padding: 8px 10px; border: 1.5px solid var(--border); border-radius: var(--radius-sm); font-size: 0.82rem; background: var(--card-bg); min-width: 120px; }

/* RESULT PANELS */
.result-panel { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; }
.result-header { padding: 12px 16px; font-size: 0.88rem; font-weight: 900; background: #f8fafc; border-bottom: 1px solid var(--border); }
.result-body { padding: 16px; }

/* COMM TEST RESULTS */
.path-display { display: flex; align-items: center; flex-wrap: wrap; gap: 4px; font-size: 0.8rem; margin: 8px 0; }
.path-node { padding: 4px 10px; border-radius: 6px; font-weight: 700; font-size: 0.78rem; background: var(--primary-light); color: var(--primary); border: 1px solid #bfdbfe; }
.path-node.dead { background: #fef2f2; color: var(--danger); border-color: #fecaca; }
.path-node.loop-node { background: #fff7ed; color: var(--clr-loop); border-color: #fed7aa; }
.path-node.server-node { background: #f0fdf4; color: var(--success); border-color: #bbf7d0; }
.path-arrow { color: var(--text-muted); font-size: 0.9rem; }
.result-row { display: flex; gap: 10px; align-items: flex-start; padding: 8px 0; border-bottom: 1px solid #f1f5f9; font-size: 0.82rem; }
.result-row:last-child { border-bottom: none; }
.result-label { font-weight: 700; color: var(--text-muted); width: 120px; flex-shrink: 0; }
.result-value { color: var(--text-primary); flex: 1; line-height: 1.6; }
.result-value.ok { color: var(--success); font-weight: 700; }
.result-value.ng { color: var(--danger); font-weight: 700; }
.result-value.warn { color: var(--warning); font-weight: 700; }

/* SCORE DISPLAY */
.score-big { text-align: center; padding: 20px 0 14px; }
.score-number { font-size: 3rem; font-weight: 900; line-height: 1; }
.score-number.perfect { color: var(--success); }
.score-number.good { color: var(--primary); }
.score-number.ok { color: var(--warning); }
.score-number.bad { color: var(--danger); }
.score-grade { font-size: 0.9rem; font-weight: 700; margin-top: 6px; }
.score-breakdown { display: flex; flex-direction: column; gap: 6px; padding: 12px 16px; }
.score-item { display: flex; justify-content: space-between; align-items: center; font-size: 0.82rem; padding: 6px 0; border-bottom: 1px solid #f1f5f9; }
.score-item:last-child { border-bottom: none; }
.score-item-label { color: var(--text-secondary); }
.score-item-pts { font-weight: 800; }
.score-item-pts.plus { color: var(--success); }
.score-item-pts.minus { color: var(--danger); }

/* HINT / SOLUTION */
.hint-box { background: #fffbeb; border: 1px solid #fde68a; border-radius: var(--radius-sm); padding: 12px 14px; font-size: 0.82rem; line-height: 1.75; color: #78350f; margin: 8px 0; }
.solution-route-item { background: #f0fdf4; border: 1px solid #bbf7d0; border-radius: var(--radius-sm); padding: 10px 12px; margin: 6px 0; font-size: 0.82rem; }
.solution-route-cmd { font-family: monospace; font-size: 0.8rem; color: var(--success); font-weight: 700; }
.solution-route-why { font-size: 0.75rem; color: var(--text-secondary); margin-top: 4px; line-height: 1.6; }
.missing-route-box { background: #fef2f2; border: 1px solid #fecaca; border-radius: var(--radius-sm); padding: 10px 12px; margin: 6px 0; font-size: 0.82rem; color: #7f1d1d; }
.candidate-route-box { background: #eff6ff; border: 1px solid #bfdbfe; border-radius: var(--radius-sm); padding: 8px 12px; margin: 4px 0; font-size: 0.78rem; color: #1e40af; font-family: monospace; }

/* LEARN SECTION */
.learn-section { max-width: 1200px; margin: 0 auto 60px; padding: 0 12px; }
.learn-header { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 18px; display: flex; justify-content: space-between; align-items: center; cursor: pointer; font-weight: 800; font-size: 0.88rem; box-shadow: var(--shadow); }
.learn-header:hover { background: #f8fafc; }
.learn-arrow { font-size: 0.8rem; color: var(--text-muted); transition: transform 0.2s; }
.learn-header.open .learn-arrow { transform: rotate(180deg); }
.learn-body { background: var(--card-bg); border: 1px solid var(--border); border-top: none; border-radius: 0 0 var(--radius) var(--radius); padding: 16px; }
.learn-grid { display: grid; grid-template-columns: 1fr; gap: 12px; }
@media (min-width: 700px) { .learn-grid { grid-template-columns: 1fr 1fr; } }
@media (min-width: 1000px) { .learn-grid { grid-template-columns: 1fr 1fr 1fr 1fr; } }
.learn-card { background: #f8fafc; border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 14px; }
.learn-card h3 { font-size: 0.82rem; font-weight: 800; color: var(--text-primary); margin-bottom: 6px; }
.learn-card p { font-size: 0.78rem; line-height: 1.75; color: var(--text-secondary); }

/* MODAL */
.modal-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.45); z-index: 500; display: flex; align-items: center; justify-content: center; padding: 20px; }
.modal-box { background: var(--card-bg); border-radius: var(--radius); box-shadow: 0 20px 60px rgba(0,0,0,0.2); width: 100%; max-width: 520px; max-height: 80vh; overflow-y: auto; }
.modal-header { display: flex; align-items: center; justify-content: space-between; padding: 14px 18px; border-bottom: 1px solid var(--border); font-weight: 800; font-size: 0.95rem; }
.modal-close { border: none; background: none; font-size: 1.1rem; cursor: pointer; color: var(--text-muted); padding: 4px 8px; border-radius: 4px; }
.modal-close:hover { background: #f1f5f9; }
.modal-body { padding: 16px 18px; }
.modal-section { margin-bottom: 14px; }
.modal-section-title { font-size: 0.75rem; font-weight: 800; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 6px; }
.modal-route-add-btn { font-size: 0.75rem; padding: 5px 12px; border-radius: 6px; border: 1.5px solid var(--primary); color: var(--primary); background: none; cursor: pointer; margin-top: 6px; }
.modal-route-add-btn:hover { background: var(--primary-light); }

/* TOAST */
.toast { position: fixed; bottom: calc(20px + env(safe-area-inset-bottom)); left: 50%; transform: translateX(-50%) translateY(20px); background: #1e293b; color: #fff; padding: 10px 20px; border-radius: 20px; font-size: 0.82rem; font-weight: 600; opacity: 0; transition: all 0.25s; z-index: 999; white-space: nowrap; pointer-events: none; }
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* SVG NODE STYLES */
.vis-node { cursor: pointer; }
.vis-node:hover .node-bg { opacity: 0.85; }
.node-bg { transition: all 0.2s; }
.node-label { font-size: 10px; fill: #1e293b; font-weight: 700; text-anchor: middle; pointer-events: none; }
.node-ip { font-size: 8.5px; fill: #64748b; text-anchor: middle; pointer-events: none; }
.node-gw-label { font-size: 8px; fill: #6366f1; text-anchor: middle; pointer-events: none; }
.seg-rect { rx: 8; ry: 8; }
.seg-label { font-size: 11px; fill: #334155; font-weight: 800; text-anchor: middle; }
.seg-cidr { font-size: 9px; fill: #64748b; text-anchor: middle; }
.link-line { stroke: #cbd5e1; stroke-width: 2; fill: none; }
.route-label { font-size: 7.5px; fill: #64748b; text-anchor: middle; pointer-events: none; }

/* SVG path highlight */
.path-fwd { stroke: var(--clr-fwd) !important; stroke-width: 3 !important; opacity: 1 !important; }
.path-rev { stroke: var(--clr-rev) !important; stroke-width: 3 !important; opacity: 1 !important; }
.path-dead { stroke: var(--clr-dead) !important; stroke-width: 3 !important; opacity: 1 !important; }
.node-highlight-fwd .node-bg { stroke: var(--clr-fwd) !important; stroke-width: 3 !important; }
.node-highlight-rev .node-bg { stroke: var(--clr-rev) !important; stroke-width: 3 !important; }
.node-highlight-dead .node-bg { stroke: var(--clr-dead) !important; stroke-width: 3 !important; }
.node-highlight-loop .node-bg { stroke: var(--clr-loop) !important; stroke-width: 3 !important; animation: node-blink 0.6s ease-in-out infinite; }

@keyframes node-blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* route added marker */
.link-user-added { stroke: var(--clr-added) !important; stroke-width: 2.5 !important; stroke-dasharray: 5,3; }

/* scrollbar */
.rtable-wrap::-webkit-scrollbar { width: 4px; }
.rtable-wrap::-webkit-scrollbar-track { background: #f1f5f9; }
.rtable-wrap::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 4px; }