/* ==============================================================================
 * Apple HIG & iPhone 16 Viewport Optimized Design System
 * Zero-dependency, Modern CSS Variables & Glassmorphism
 * ============================================================================== */

:root {
  --bg-primary: #07090e;
  --bg-secondary: #0e131f;
  --bg-tertiary: #161c2d;
  --bg-card: rgba(22, 28, 45, 0.7);
  --bg-card-hover: rgba(30, 41, 69, 0.85);

  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-active: rgba(56, 189, 248, 0.5);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --accent-cyan: #38bdf8;
  --accent-blue: #60a5fa;
  --accent-indigo: #818cf8;
  --accent-emerald: #34d399;
  --accent-amber: #fbbf24;
  --accent-rose: #f43f5e;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  --safe-top: env(safe-area-inset-top, 20px);
  --safe-bottom: env(safe-area-inset-bottom, 20px);
  --safe-left: env(safe-area-inset-left, 0px);
  --safe-right: env(safe-area-inset-right, 0px);

  --tap-target-min: 44px;
  --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", sans-serif;
  --font-mono: "SF Mono", "Fira Code", Menlo, monospace;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  padding-top: var(--safe-top);
  padding-bottom: calc(var(--safe-bottom) + 68px); /* Space for bottom tab bar */
}

/* --- Dynamic Island Header --- */
.ios-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  background: rgba(7, 9, 14, 0.85);
  border-bottom: 1px solid var(--border-subtle);
  padding: 10px 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.island-capsule {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #000;
  border-radius: var(--radius-full);
  padding: 6px 14px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.6);
}

.island-left {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 600;
  color: #fff;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent-emerald);
  box-shadow: 0 0 10px var(--accent-emerald);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

.island-right {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  font-family: var(--font-mono);
  color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.12);
  padding: 3px 8px;
  border-radius: var(--radius-full);
}

.app-branding {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  padding: 4px 0 2px;
}

.app-title-group h1 {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.5px;
  background: linear-gradient(135deg, #fff 30%, var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.app-title-group p {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 2px;
}

.badge-4xgpu {
  font-size: 11px;
  font-weight: 600;
  background: linear-gradient(135deg, rgba(129, 140, 248, 0.2), rgba(56, 189, 248, 0.2));
  color: var(--accent-cyan);
  border: 1px solid var(--border-active);
  padding: 4px 10px;
  border-radius: var(--radius-full);
}

/* --- Container & View Switcher --- */
.main-container {
  flex: 1;
  max-width: 1040px;
  margin: 0 auto;
  width: 100%;
  padding: 12px 16px;
}

.view-section {
  display: none;
  animation: fadeIn 0.25s ease-out;
}

.view-section.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* --- Panorama Topology Map --- */
.map-canvas-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 16px;
  margin-bottom: 16px;
  position: relative;
  overflow: hidden;
}

.map-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}

.map-hint {
  font-size: 12px;
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  gap: 4px;
}

/* Grid Layout for Topology Nodes */
.topology-flow {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  position: relative;
}

.flow-node {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 14px 10px;
  min-height: 80px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  user-select: none;
}

.flow-node:active {
  transform: scale(0.96);
}

.flow-node.selected {
  border-color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.12);
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.25);
}

.node-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.node-sub {
  font-size: 10px;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* Node Detail Inspector Card */
.inspector-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 18px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.5);
  margin-bottom: 20px;
}

.inspector-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-subtle);
}

.inspector-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
}

.inspector-summary {
  font-size: 14px;
  color: var(--accent-blue);
  line-height: 1.5;
  margin-bottom: 14px;
  background: rgba(96, 165, 250, 0.08);
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent-blue);
}

.inspector-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.inspect-box {
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.inspect-box h4 {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.box-what h4 { color: var(--accent-cyan); }
.box-metrics h4 { color: var(--accent-emerald); }
.box-symptoms h4 { color: var(--accent-amber); }
.box-moe h4 { color: var(--accent-rose); }

.inspect-box p, .inspect-box pre {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.5;
  white-space: pre-line;
}

/* --- Learning Roadmap Pills --- */
.roadmap-section {
  margin-top: 20px;
}

.roadmap-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 10px;
}

.roadmap-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.pill-item {
  font-size: 12px;
  font-weight: 500;
  padding: 8px 14px;
  border-radius: var(--radius-full);
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
  min-height: var(--tap-target-min);
  display: inline-flex;
  align-items: center;
}

.pill-item:hover, .pill-item:active {
  background: var(--bg-tertiary);
  border-color: var(--accent-cyan);
  color: var(--text-primary);
}

/* --- Calculator Module --- */
.calc-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 20px;
  margin-bottom: 20px;
}

.calc-title {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.form-group {
  margin-bottom: 14px;
}

.form-label {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.form-label span.val {
  font-family: var(--font-mono);
  color: var(--accent-cyan);
  font-weight: 600;
}

select, input[type="range"], input[type="number"] {
  width: 100%;
  min-height: var(--tap-target-min);
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  font-size: 14px;
  padding: 8px 12px;
  outline: none;
}

select:focus, input:focus {
  border-color: var(--accent-cyan);
}

.calc-results-panel {
  background: rgba(14, 19, 31, 0.9);
  border: 1px solid var(--border-active);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.metric-kpi {
  display: flex;
  flex-direction: column;
}

.metric-label {
  font-size: 11px;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.metric-value {
  font-size: 20px;
  font-weight: 700;
  font-family: var(--font-mono);
  color: var(--accent-cyan);
}

.metric-sub {
  font-size: 11px;
  color: var(--accent-emerald);
  margin-top: 2px;
}

/* --- Diagnostic Lab Case Cards --- */
.case-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 20px;
  margin-bottom: 18px;
  transition: border-color 0.2s;
}

.case-badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  background: rgba(129, 140, 248, 0.15);
  color: var(--accent-indigo);
  padding: 3px 8px;
  border-radius: var(--radius-full);
  margin-bottom: 10px;
}

.case-title {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 10px;
  line-height: 1.4;
}

.case-desc {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 16px;
}

.case-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 14px;
}

.option-btn {
  width: 100%;
  min-height: var(--tap-target-min);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  text-align: left;
  font-size: 13px;
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  transition: all 0.2s;
}

.option-btn:hover {
  background: var(--bg-card-hover);
  border-color: rgba(255, 255, 255, 0.18);
}

.option-btn.selected-correct {
  border-color: var(--accent-emerald);
  background: rgba(52, 211, 153, 0.12);
  color: #a7f3d0;
}

.option-btn.selected-incorrect {
  border-color: var(--accent-rose);
  background: rgba(244, 63, 94, 0.12);
  color: #fecdd3;
}

.option-prefix {
  font-weight: 700;
  font-family: var(--font-mono);
  color: var(--accent-cyan);
}

.feedback-box {
  display: none;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 14px;
  margin-top: 14px;
  font-size: 13px;
  line-height: 1.5;
  border-left: 4px solid var(--accent-cyan);
}

.feedback-box.show {
  display: block;
}

.code-block {
  background: #000;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 10px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: #38bdf8;
  overflow-x: auto;
  margin-top: 8px;
}

/* --- iOS Bottom Tab Bar (HIG Compliant) --- */
.ios-tab-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: calc(56px + var(--safe-bottom));
  padding-bottom: var(--safe-bottom);
  background: rgba(14, 19, 31, 0.92);
  backdrop-filter: blur(25px);
  -webkit-backdrop-filter: blur(25px);
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-around;
  z-index: 100;
}

.tab-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  min-width: 60px;
  min-height: var(--tap-target-min);
  cursor: pointer;
  transition: all 0.2s;
}

.tab-icon {
  font-size: 18px;
  transition: transform 0.2s;
}

.tab-label {
  font-size: 10px;
  font-weight: 600;
}

.tab-btn.active {
  color: var(--accent-cyan);
}

.tab-btn.active .tab-icon {
  transform: translateY(-2px);
}

/* --- Media Queries (iPhone 16 Viewport up to Desktop) --- */
@media (min-width: 768px) {
  .topology-flow {
    grid-template-columns: repeat(5, 1fr);
  }
  .inspector-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .calc-results-panel {
    grid-template-columns: repeat(4, 1fr);
  }
}