/* ==========================================================================
   PID CONTROLLER — PURE MATHEMATICAL RESPONSE VISUALIZER STYLESHEET
   InstruVerse / Prayogsetu Virtual Instrumentation Lab
   ========================================================================== */

:root {
  /* Color Palette - Dark Technical Control Laboratory */
  --bg-core: #090c10;
  --bg-panel: #0d1117;
  --bg-card: #161b22;
  --bg-subtle: #1c2128;
  --bg-input: #0b0f14;

  --border-subtle: #21262d;
  --border-strong: #30363d;
  --border-focus: #58a6ff;

  --text-primary: #f0f6fc;
  --text-secondary: #8b949e;
  --text-muted: #57606a;

  /* Engineering Signal Colors */
  --color-ref: #38bdf8;         /* Cyan for Reference Step */
  --color-resp: #10b981;        /* Emerald Green for PID Response */
  --color-kp: #a855f7;          /* Purple for P */
  --color-ki: #3b82f6;          /* Royal Blue for I */
  --color-kd: #f59e0b;          /* Amber/Orange for D */
  --color-u: #ec4899;           /* Pink for Total Output */

  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-panel: 0 4px 20px rgba(0, 0, 0, 0.4);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: var(--bg-core);
  color: var(--text-primary);
  font-family: var(--font-sans);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  line-height: 1.45;
  font-size: 14px;
  overflow-x: hidden;
}

/* ==========================================================================
   Header
   ========================================================================== */
.lab-header {
  background: var(--bg-panel);
  border-bottom: 1px solid var(--border-subtle);
  padding: 12px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
}

.header-left {
  display: flex;
  flex-direction: column;
}

.brand-badge {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 2px;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  background: #10b981;
  border-radius: 50%;
  box-shadow: 0 0 10px #10b981;
}

.instru-logo {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.5px;
  color: #58a6ff;
  text-transform: uppercase;
}

.lab-title {
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.2px;
  color: #fff;
}

.accent-title {
  font-weight: 500;
  color: var(--text-secondary);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-link-btn {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: #94a3b8;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  padding: 6px 14px;
  border-radius: 20px;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all 0.2s ease;
}

.nav-link-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #38bdf8;
  border-color: #38bdf8;
}

.status-badge {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: #38bdf8;
  letter-spacing: 0.5px;
  background: rgba(56, 189, 248, 0.1);
  padding: 6px 12px;
  border-radius: 20px;
  border: 1px solid rgba(56, 189, 248, 0.25);
}

/* ==========================================================================
   Main Layout Grid (Parameters on Left, Large PID Response on Right)
   ========================================================================== */
.lab-main-container {
  flex: 1;
  padding: 18px 24px;
  max-width: 1560px;
  width: 100%;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
}

.main-layout-grid {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 20px;
  align-items: stretch;
  flex: 1;
}

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

.panel {
  background: var(--bg-panel);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 18px;
  box-shadow: var(--shadow-panel);
  display: flex;
  flex-direction: column;
}

.main-response-panel {
  min-height: 480px;
  display: flex;
  flex-direction: column;
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-subtle);
}

.panel-title-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
}

.panel-title-wrap h2 {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.6px;
  color: var(--text-primary);
  text-transform: uppercase;
}

.icon {
  color: #58a6ff;
}

.badge-manual, .badge-active, .badge-edu {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.badge-manual {
  background: rgba(168, 85, 247, 0.15);
  color: #c084fc;
  border: 1px solid rgba(168, 85, 247, 0.3);
}

.badge-active {
  background: rgba(16, 185, 129, 0.15);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.badge-edu {
  background: rgba(245, 158, 11, 0.15);
  color: #fbbf24;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

/* ==========================================================================
   PID Parameter Sliders
   ========================================================================== */
.parameters-panel {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.sliders-wrapper {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.slider-control-group {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 10px 14px;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.slider-control-group:hover {
  border-color: var(--border-strong);
}

.slider-control-group.group-kp:focus-within {
  border-color: var(--color-kp);
  box-shadow: 0 0 12px rgba(168, 85, 247, 0.2);
}

.slider-control-group.group-ki:focus-within {
  border-color: var(--color-ki);
  box-shadow: 0 0 12px rgba(59, 130, 246, 0.2);
}

.slider-control-group.group-kd:focus-within {
  border-color: var(--color-kd);
  box-shadow: 0 0 12px rgba(245, 158, 11, 0.2);
}

.slider-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.param-label {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
}

.term-tag {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 800;
  width: 22px;
  height: 22px;
  border-radius: 4px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
}

.tag-p { background: var(--color-kp); }
.tag-i { background: var(--color-ki); }
.tag-d { background: var(--color-kd); }

.term-name {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
}

.value-display-box {
  background: var(--bg-input);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 3px 10px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  color: var(--text-primary);
  min-width: 60px;
  text-align: right;
}

.slider-track-container {
  position: relative;
  padding: 4px 0;
}

.custom-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: #21262d;
  outline: none;
  cursor: pointer;
  transition: background 0.2s;
}

.custom-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid #ffffff;
  box-shadow: 0 0 8px rgba(0,0,0,0.8);
  transition: transform 0.1s, box-shadow 0.2s;
}

.custom-slider::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid #ffffff;
  box-shadow: 0 0 8px rgba(0,0,0,0.8);
}

.slider-kp::-webkit-slider-thumb { background: var(--color-kp); box-shadow: 0 0 10px var(--color-kp); }
.slider-ki::-webkit-slider-thumb { background: var(--color-ki); box-shadow: 0 0 10px var(--color-ki); }
.slider-kd::-webkit-slider-thumb { background: var(--color-kd); box-shadow: 0 0 10px var(--color-kd); }

.slider-kp::-moz-range-thumb { background: var(--color-kp); }
.slider-ki::-moz-range-thumb { background: var(--color-ki); }
.slider-kd::-moz-range-thumb { background: var(--color-kd); }

.custom-slider:hover::-webkit-slider-thumb {
  transform: scale(1.15);
}

.slider-bounds {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-muted);
  margin-top: 4px;
}

.range-hint {
  color: var(--text-secondary);
}

/* Reset Button */
.reset-container {
  margin-top: 4px;
}

.btn-reset-all {
  width: 100%;
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 700;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  color: #94a3b8;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.15s ease-in-out;
  letter-spacing: 0.3px;
}

.btn-reset-all:hover {
  background: var(--bg-subtle);
  border-color: #ef4444;
  color: #f87171;
  box-shadow: 0 0 10px rgba(239, 68, 68, 0.2);
}

/* Math Card */
.math-reference-card {
  background: rgba(56, 189, 248, 0.04);
  border: 1px solid rgba(56, 189, 248, 0.2);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  margin-top: auto;
}

.math-card-title {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  color: #38bdf8;
  letter-spacing: 0.8px;
  margin-bottom: 6px;
}

.formula-box {
  font-family: var(--font-mono);
  font-size: 11px;
  color: #f0f6fc;
  background: var(--bg-input);
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  margin-bottom: 6px;
  text-align: center;
}

.math-desc {
  font-size: 11px;
  color: var(--text-muted);
  line-height: 1.35;
}

/* ==========================================================================
   Graphs Stack (Right Side)
   ========================================================================== */
.graphs-stack {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.graph-panel {
  min-height: 310px;
}

.graph-indicator-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
}

.dot-cyan { background: var(--color-ref); box-shadow: 0 0 8px var(--color-ref); }
.dot-multi { background: var(--color-u); box-shadow: 0 0 8px var(--color-u); }

.graph-legend {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.legend-item {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
}

.legend-dash {
  width: 14px;
  height: 2px;
  background: var(--color-ref);
  display: inline-block;
  border-bottom: 1px dashed var(--color-ref);
}

.legend-line {
  width: 14px;
  height: 2px;
  background: var(--color-resp);
  display: inline-block;
}

.legend-line.p-color { background: var(--color-kp); }
.legend-line.i-color { background: var(--color-ki); }
.legend-line.d-color { background: var(--color-kd); }
.legend-line.u-color { background: var(--color-u); }

.canvas-container {
  position: relative;
  flex: 1;
  width: 100%;
  min-height: 420px;
  background: #06090e;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  display: flex;
}

canvas {
  width: 100% !important;
  height: 100% !important;
  display: block;
}

.graph-watermark {
  position: absolute;
  right: 14px;
  bottom: 10px;
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 1px;
  color: rgba(255, 255, 255, 0.08);
  pointer-events: none;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.lab-footer {
  background: var(--bg-panel);
  border-top: 1px solid var(--border-subtle);
  padding: 10px 24px;
  margin-top: auto;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-muted);
  max-width: 1600px;
  margin: 0 auto;
}

@media (max-width: 768px) {
  .footer-content {
    flex-direction: column;
    gap: 4px;
    text-align: center;
  }
}