/* --- Design System & CSS Variables --- */
:root {
  --font-sans: 'Plus Jakarta Sans', system-ui, sans-serif;
  --font-mono: 'Fira Code', monospace;
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  
  --transition-fast: 0.15s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-normal: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 10px 35px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.15);
}

/* --- Dark Theme Variables --- */
body.dark-theme {
  --bg-app: #050608;
  --bg-panel: #0a0c10;
  --bg-card: rgba(16, 18, 25, 0.6);
  --bg-card-hover: rgba(23, 26, 37, 0.85);
  --bg-input: #0f121a;
  --border-color: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(255, 255, 255, 0.12);
  
  --text-primary: #eff1f5;
  --text-secondary: #9aa0b2;
  --text-muted: #5e6375;
  
  --accent-color: #3b82f6;
  --accent-color-hover: #2563eb;
  --accent-gradient: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
  --accent-glow: rgba(59, 130, 246, 0.25);
  
  --toast-bg: rgba(10, 12, 16, 0.95);
  --toast-border: rgba(59, 130, 246, 0.3);
  --color-success: #10b981;
  --color-warning: #f59e0b;
}

/* --- Light Theme Variables --- */
body.light-theme {
  --bg-app: #f0f2f5;
  --bg-panel: #ffffff;
  --bg-card: rgba(239, 241, 244, 0.8);
  --bg-card-hover: rgba(239, 241, 244, 1);
  --bg-input: #ffffff;
  --border-color: rgba(0, 0, 0, 0.08);
  --border-hover: rgba(0, 0, 0, 0.15);
  
  --text-primary: #1f2937;
  --text-secondary: #4b5563;
  --text-muted: #9ca3af;
  
  --accent-color: #2563eb;
  --accent-color-hover: #1d4ed8;
  --accent-gradient: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
  --accent-glow: rgba(37, 99, 235, 0.15);
  
  --toast-bg: rgba(255, 255, 255, 0.95);
  --toast-border: rgba(37, 99, 235, 0.2);
  --color-success: #059669;
  --color-warning: #d97706;
}

/* --- Reset & Layout --- */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-app);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-app);
}

::-webkit-scrollbar-thumb {
  background: var(--text-muted);
  border-radius: 99px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-secondary);
}

.app-container {
  width: 100%;
  max-width: 1540px;
  margin: 0 auto;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  flex-grow: 1;
}

/* --- Header --- */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo-icon-wrapper {
  background: var(--accent-gradient);
  color: white;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  box-shadow: 0 4px 14px var(--accent-glow);
}

.logo-icon {
  width: 20px;
  height: 20px;
}

.header-logo h1 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 0.8rem;
}

/* Theme Toggle Button */
.theme-toggle-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.theme-toggle-btn:hover {
  background: var(--bg-card-hover);
  transform: translateY(-1px);
}

body.dark-theme .sun-icon,
body.light-theme .moon-icon {
  display: block;
}

body.dark-theme .moon-icon,
body.light-theme .sun-icon {
  display: none;
}

.theme-toggle-btn svg {
  width: 18px;
  height: 18px;
}

/* --- Main Workspace Layout --- */
.app-main {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 1.5rem;
  flex-grow: 1;
  min-height: 0;
  height: calc(100vh - 120px);
}

@media (max-width: 1024px) {
  .app-main {
    grid-template-columns: 1fr;
    height: auto;
  }
}

.panel {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  height: 100%;
  min-height: 0;
  overflow-y: auto;
  padding-right: 4px;
}

/* --- Card Abstraction --- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  backdrop-filter: blur(10px);
}

.card-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
  position: relative;
}

.card-header svg {
  color: var(--accent-color);
  width: 20px;
  height: 20px;
}

.card-header h2 {
  font-size: 1.1rem;
  font-weight: 600;
}

.controls-grid {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* --- Form Sliders & Groups --- */
.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.control-group label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.badge {
  background: var(--accent-color);
  color: white;
  padding: 1px 8px;
  border-radius: 99px;
  font-size: 0.75rem;
  font-weight: 700;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 5px;
  border-radius: 99px;
  background: var(--bg-input);
  outline: none;
  border: 1px solid var(--border-color);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent-color);
  cursor: pointer;
  border: 2.5px solid #fff;
  box-shadow: 0 1px 3px rgba(0,0,0,0.3);
  transition: transform var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.input-group label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.custom-select {
  font-family: var(--font-sans);
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.65rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  outline: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.custom-select:hover {
  border-color: var(--border-hover);
}

/* Button */
.btn {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  transition: all var(--transition-fast);
}

.btn-primary {
  background: var(--accent-gradient);
  color: white;
  box-shadow: 0 4px 12px var(--accent-glow);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 18px var(--accent-glow);
  filter: brightness(1.05);
}

/* --- Telemetry Panel --- */
.telemetry-status {
  position: absolute;
  right: 0;
  font-size: 0.75rem;
  font-weight: 700;
  font-family: var(--font-mono);
  color: var(--color-warning);
}

.telemetry-content {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

#convergence-chart {
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  width: 100%;
  height: 150px;
}

.telemetry-metrics {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 0.75rem;
}

.metric {
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.metric-label {
  font-size: 0.65rem;
  font-weight: 600;
  color: var(--text-muted);
  text-align: center;
}

.metric-value {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-primary);
  font-family: var(--font-mono);
  margin-top: 2px;
}

/* --- Results Stack Cards --- */
.stack-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

@media (max-width: 640px) {
  .stack-grid {
    grid-template-columns: 1fr;
  }
}

.stack-item {
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.85rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  transition: all var(--transition-fast);
}

.stack-item svg {
  color: var(--text-muted);
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.stack-info h3 {
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
}

.stack-info p {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 2px;
}

/* Highlights active recommendations */
.stack-item.active {
  border-color: rgba(59, 130, 246, 0.4);
  background: rgba(59, 130, 246, 0.05);
}

.stack-item.active svg {
  color: var(--accent-color);
}

/* --- Cost Panel --- */
.cost-panel {
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.cost-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 0.5rem;
  border-bottom: 1px dashed var(--border-color);
  font-size: 0.85rem;
}

.cost-header span {
  font-weight: 600;
  color: var(--text-secondary);
}

.cost-header strong {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-success);
  font-family: var(--font-mono);
}

.cost-detail-grid {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.cost-detail-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.cost-detail-row span {
  font-weight: 500;
}

.cost-detail-row strong {
  font-family: var(--font-mono);
  color: var(--text-primary);
}

/* --- Topology SVG --- */
.topology-wrapper {
  display: flex;
  justify-content: center;
  align-items: center;
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.5rem;
}

#topology-svg {
  width: 100%;
  height: auto;
  max-height: 240px;
}

.svg-node rect {
  fill: var(--bg-panel);
  stroke: var(--border-color);
  stroke-width: 1.5px;
  transition: all var(--transition-normal);
}

.svg-node text {
  text-anchor: middle;
  pointer-events: none;
  font-family: var(--font-sans);
}

.svg-node .node-title {
  font-size: 11px;
  font-weight: 700;
  fill: var(--text-primary);
}

.svg-node .node-sub {
  font-size: 9px;
  font-weight: 600;
  fill: var(--text-muted);
  font-family: var(--font-mono);
}

/* Inactive states */
.svg-node {
  opacity: 0.35;
  transition: opacity var(--transition-normal);
}

/* Active node glow animations */
.svg-node.active {
  opacity: 1;
}

.svg-node.active rect {
  fill: rgba(59, 130, 246, 0.08);
  stroke: var(--accent-color);
  filter: drop-shadow(0 0 5px var(--accent-glow));
}

.svg-node.active text.node-title {
  fill: var(--accent-color);
}

.svg-node.active text.node-sub {
  fill: var(--text-primary);
}

/* Active path connector lines */
.active-path {
  stroke: var(--accent-color) !important;
  stroke-width: 2.5px !important;
  stroke-dasharray: 0 !important;
  marker-end: url(#arrow-active) !important;
}

/* --- Toast Popups --- */
.toast-container {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  z-index: 9999;
}

.toast {
  background: var(--toast-bg);
  border: 1px solid var(--toast-border);
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  padding: 0.85rem 1.25rem;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  transform: translateY(20px);
  opacity: 0;
  animation: toast-in 0.3s cubic-bezier(0.16, 1, 0.3, 1) forwards;
  backdrop-filter: blur(10px);
}

.toast svg {
  color: var(--color-success);
  width: 16px;
  height: 16px;
}

.toast-message {
  font-size: 0.85rem;
  font-weight: 500;
}

@keyframes toast-in {
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.toast.fade-out {
  animation: toast-out 0.3s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes toast-out {
  to {
    transform: translateY(10px);
    opacity: 0;
  }
}

.hidden {
  display: none !important;
}