:root {
  --navy: #2c3e50;
  --softgray: #e9ecef;
  --teal: #1abc9c;
  --gold: #f1c40f;
  --slate: #556366;
  --coral: #e74c3c;
  --white: #ffffff;
  --gray-100: #f7fafc;
  --gray-200: #edf2f7;
  --gray-300: #e2e8f0;
  --max-width: 1120px;
  --container-pad: 16px;
  --radius: 10px;
  --shadow-sm: 0 6px 18px rgba(0, 0, 0, 0.06);
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.06);
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: 'Montserrat', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
  color: var(--navy);
  background: linear-gradient(135deg, #ecf0f1 0%, #d6dbdf 100%);
  padding: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding: 18px;
}

li {
  line-height: 2;
}

/* Page header */
.header-left {
  justify-self: start;
}

.page-header {
  text-align: center;
  color: var(--navy);
  padding: 1rem;
  position: relative;
}

.header-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 12px;
  padding: 8px 0;
}

.page-title {
  margin: 0;
  justify-self: center;
  font-size: 2rem;
  font-weight: 700;
  font-family: 'Montserrat', sans-serif;
}

.header-actions {
  justify-self: end;
}

.cols {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.experiment-area {
  background: var(--gray-100);
  border-radius: 10px;
  padding: 20px;
  margin-bottom: 24px;
}

.sim-area {
  background: var(--softgray);
  border-radius: 8px;
  padding: 12px;
  position: relative;
  overflow: hidden;
  height: 400px;
}

/* Controls */
.controls {
  background: white;
  border-radius: 8px;
  padding: 16px;
  box-shadow: var(--shadow-sm);
}

.control-group {
  margin-bottom: 18px;
}

.label {
  display: block;
  margin-bottom: 6px;
  font-size: 14px;
  color: var(--slate);
  font-weight: 600;
}

.range-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.range {
  flex: 1;
}

.value {
  display: inline-block;
  padding: 6px 8px;
  border-radius: 6px;
  background: rgba(26, 188, 156, 0.12);
  color: var(--teal);
  min-width: 64px;
  text-align: center;
  font-weight: 700;
}

/* Button styles */
.teal-btn {
  background-color: rgba(26, 188, 156, 0.8);
  color: white;
}

.teal-btn:hover {
  background-color: rgba(26, 188, 156, 0.7);
  transform: translateY(-2px);
}

.gold-btn {
  background-color: rgba(241, 196, 15, 1);
  color: var(--navy);
  opacity: 0.9;
}

.gold-btn:hover {
  background-color: rgba(241, 196, 15, 0.5);
  transform: translateY(-2px);
}

.coral-btn {
  background-color: rgba(231, 76, 60, 0.8);
  color: white;
}

.coral-btn:hover {
  background-color: rgba(231, 76, 60, 0.7);
  transform: translateY(-2px);
}

.navy-btn {
  background-color: rgba(44, 62, 80, 0.8);
  color: white;
}

.navy-btn:hover {
  background-color: rgba(44, 62, 80, 0.7);
  transform: translateY(-2px);
}

.button-stack {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 24px;
}

.btn {
  display: inline-block;
  padding: 12px 24px;
  border-radius: 0.375rem;
  font-weight: 600;
  font-size: 16px;
  text-decoration: none;
  text-align: center;
  transition: all 0.2s;
  cursor: pointer;
  border: 1px solid transparent;
}

/* Panels */
.panel {
  margin-top: 24px;
  background: white;
  border-radius: 8px;
  padding: 16px;
  box-shadow: var(--shadow-sm);
}

.panel h3 {
  margin: 0 0 12px 0;
  font-size: 18px;
}

.panel .panel-body {
  color: var(--navy);
}

.panel ol,
.panel ul {
  margin: 8px 0 0 20px;
}

/* Results table */
.table-wrap {
  overflow-x: auto;
}

.results-table {
  width: 100%;
  border-collapse: collapse;
  background: white;
  border: 1px solid var(--softgray);
}

.results-table th,
.results-table td {
  border: 1px solid var(--softgray);
  padding: 8px;
  text-align: left;
}

.results-table thead tr {
  background: var(--softgray);
}

.results-table th {
  font-weight: 700;
}

.row-delete {
  background: none;
  border: 0;
  cursor: pointer;
  color: #e53e3e;
  font-size: 16px;
}

.table-input {
  width: 100%;
  max-width: 160px;
  padding: 8px;
  border-radius: 6px;
  border: 1px solid var(--gray-300);
  background: white;
  font: inherit;
  color: var(--navy);
  text-align: center;
}

.table-input:focus {
  outline: 3px solid rgba(26, 188, 156, 0.18);
  outline-offset: 2px;
}

.status {
  text-align: center;
  padding: 10px;
  border-radius: 5px;
  margin: 10px 0;
  font-weight: 600;
}

/* Range input styling */
input[type='range'] {
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  background: transparent;
}

input[type='range']:focus {
  outline: none;
}

input[type='range']::-webkit-slider-runnable-track {
  height: 6px;
  background: linear-gradient(90deg, #d0d0d0, #bdbdbd);
  border-radius: 6px;
}

input[type='range']::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--navy);
  margin-top: -6px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

input[type='range']::-moz-range-track {
  height: 6px;
  background: linear-gradient(90deg, #d0d0d0, #bdbdbd);
  border-radius: 6px;
}

input[type='range']::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--navy);
  border: none;
}

/* Accessibility focus states */
a:focus,
button:focus,
input:focus {
  outline: 3px solid rgba(26, 188, 156, 0.18);
  outline-offset: 2px;
}

/* LDR Simulation Styles */
.rig {
  position: relative;
  width: 100%;
  height: 100%;
  border-radius: 10px;
  background: radial-gradient(
      circle at 18% 20%,
      rgba(255, 255, 255, 0.65),
      rgba(255, 255, 255, 0) 55%
    ),
    radial-gradient(circle at 90% 15%, rgba(255, 255, 255, 0.4), rgba(255, 255, 255, 0) 50%),
    linear-gradient(180deg, #ffffff 0%, #f2f4f7 100%);
  border: 1px solid rgba(44, 62, 80, 0.12);
  box-shadow: var(--shadow-xs);
  overflow: hidden;
}

.rig::after {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    90deg,
    rgba(44, 62, 80, 0.03),
    rgba(44, 62, 80, 0.03) 1px,
    rgba(255, 255, 255, 0) 1px,
    rgba(255, 255, 255, 0) 12px
  );
  opacity: 0.35;
  pointer-events: none;
}

/* Wires */
.wires {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 5;
}

.wire {
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
  opacity: 0.95;
}

.wire-red {
  stroke: rgba(231, 76, 60, 0.95);
  stroke-width: 7.2;
}

.wire-black {
  stroke: rgba(20, 25, 35, 0.92);
  stroke-width: 6.2;
}

/* Lamp */
.lamp-block {
  position: absolute;
  left: 10%;
  top: 10%;
  z-index: 6;
  display: grid;
  justify-items: center;
  gap: 8px;
}

.bulb-tag {
  font-size: 12px;
  font-weight: 700;
  color: var(--navy);
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(241, 196, 15, 0.18);
  border: 1px solid rgba(241, 196, 15, 0.3);
}

.bulb {
  position: relative;
  width: 92px;
  height: 150px;
}

.bulb-glow {
  position: absolute;
  left: -40px;
  top: -40px;
  width: 172px;
  height: 172px;
  border-radius: 50%;
  background: radial-gradient(
    circle,
    rgba(241, 196, 15, 0.7),
    rgba(241, 196, 15, 0.18) 46%,
    rgba(241, 196, 15, 0) 72%
  );
  opacity: 0.3;
  filter: blur(1px);
  pointer-events: none;
  transition: opacity 120ms ease, transform 120ms ease;
}

.bulb-glass {
  position: absolute;
  left: 10px;
  top: 0;
  width: 72px;
  height: 90px;
  border-radius: 999px;
  background: radial-gradient(
      circle at 30% 30%,
      rgba(255, 255, 255, 0.95),
      rgba(255, 255, 255, 0.2) 35%,
      rgba(255, 255, 255, 0.06) 55%,
      rgba(255, 255, 255, 0) 75%
    ),
    radial-gradient(circle at 60% 60%, rgba(241, 196, 15, 0.2), rgba(241, 196, 15, 0) 60%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.28), rgba(255, 255, 255, 0.05));
  border: 2px solid rgba(44, 62, 80, 0.25);
  box-shadow: inset 0 -10px 18px rgba(0, 0, 0, 0.06);
}

.bulb-filament {
  position: absolute;
  left: 50%;
  top: 46px;
  width: 34px;
  height: 18px;
  transform: translateX(-50%);
  border-radius: 9px;
  border: 2px solid rgba(44, 62, 80, 0.35);
  background: rgba(241, 196, 15, 0.1);
  box-shadow: 0 0 0 rgba(241, 196, 15, 0);
  transition: box-shadow 120ms ease, background 120ms ease;
}

.bulb-highlight {
  position: absolute;
  left: 28px;
  top: 12px;
  width: 12px;
  height: 60px;
  border-radius: 999px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.85), rgba(255, 255, 255, 0));
  opacity: 0.7;
  transform: rotate(-10deg);
}

.bulb-cap {
  position: absolute;
  left: 20px;
  top: 84px;
  width: 52px;
  height: 20px;
  border-radius: 12px;
  background: linear-gradient(180deg, rgba(44, 62, 80, 0.18), rgba(44, 62, 80, 0.1));
  border: 1px solid rgba(44, 62, 80, 0.18);
}

.bulb-thread {
  position: absolute;
  left: 24px;
  top: 102px;
  width: 44px;
  height: 20px;
  border-radius: 10px;
  background: repeating-linear-gradient(
    180deg,
    rgba(44, 62, 80, 0.22),
    rgba(44, 62, 80, 0.22) 3px,
    rgba(44, 62, 80, 0.12) 3px,
    rgba(44, 62, 80, 0.12) 6px
  );
  border: 1px solid rgba(44, 62, 80, 0.18);
}

.bulb-base {
  position: absolute;
  left: 20px;
  top: 122px;
  width: 52px;
  height: 18px;
  border-radius: 10px;
  background: rgba(44, 62, 80, 0.14);
}

/* LDR Component */
.ldr-block {
  position: absolute;
  left: 60%;
  top: 10%;
  width: 180px;
  height: 150px;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.85);
  border: 1px solid rgba(44, 62, 80, 0.14);
  box-shadow: var(--shadow-xs);
  padding: 10px;
  z-index: 6;
  overflow: hidden;
}

.ldr-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.ldr-title {
  font-weight: 800;
  color: var(--teal);
  background: rgba(26, 188, 156, 0.12);
  border: 1px solid rgba(26, 188, 156, 0.28);
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
}

.ldr-terminals {
  display: flex;
  gap: 8px;
}

.terminal {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: rgba(44, 62, 80, 0.22);
  border: 2px solid rgba(44, 62, 80, 0.22);
  box-shadow: inset 0 1px 2px rgba(255, 255, 255, 0.65);
}

.ldr-body {
  margin-top: 10px;
  display: grid;
  justify-items: center;
  gap: 10px;
}

.ldr-disc {
  position: relative;
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: radial-gradient(
      circle at 35% 30%,
      rgba(255, 255, 255, 0.95),
      rgba(255, 255, 255, 0.62) 40%,
      rgba(240, 240, 240, 0.45) 70%
    ),
    linear-gradient(180deg, rgba(255, 255, 255, 0.35), rgba(0, 0, 0, 0.03));
  border: 2px solid rgba(44, 62, 80, 0.18);
  box-shadow: 0 10px 18px rgba(0, 0, 0, 0.06);
  overflow: hidden;
}

.ldr-serpentine {
  position: absolute;
  inset: 11px;
  border-radius: 999px;
  background: repeating-linear-gradient(
    90deg,
    rgba(170, 120, 60, 0.95),
    rgba(170, 120, 60, 0.95) 3.5px,
    rgba(255, 255, 255, 0) 3.5px,
    rgba(255, 255, 255, 0) 8px
  );
  transform: rotate(12deg);
  opacity: 0.9;
}

.ldr-serpentine.s2 {
  inset: 16px;
  transform: rotate(-8deg);
  opacity: 0.8;
}

.ldr-shine {
  position: absolute;
  left: 14px;
  top: 8px;
  width: 12px;
  height: 48px;
  border-radius: 999px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.9), rgba(255, 255, 255, 0));
  opacity: 0.75;
  transform: rotate(-12deg);
}

.ldr-lightwash {
  position: absolute;
  inset: 0;
  background: radial-gradient(
    circle at 35% 35%,
    rgba(241, 196, 15, 0.55),
    rgba(241, 196, 15, 0) 60%
  );
  opacity: 0.18;
  pointer-events: none;
  transition: opacity 120ms ease;
}

/* Meter */
.meter {
  position: absolute;
  right: 24px;
  top: 60%;
  width: 300px;
  border-radius: 10px;
  background: #101a24;
  border: 1px solid rgba(44, 62, 80, 0.2);
  box-shadow: var(--shadow-sm);
  padding: 14px;
  z-index: 6;
  color: white;
}

.meter-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 10px;
}

.meter-name {
  font-weight: 800;
  letter-spacing: 0.6px;
  font-size: 12px;
  color: rgba(255, 255, 255, 0.9);
}

.meter-mode {
  font-weight: 900;
  font-size: 12px;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(26, 188, 156, 0.18);
  border: 1px solid rgba(26, 188, 156, 0.3);
}

.meter-jacks {
  position: absolute;
  right: 14px;
  top: 44px;
  display: flex;
  gap: 10px;
}

.jack {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.25);
  background: rgba(255, 255, 255, 0.06);
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.3);
}

.jack-red {
  outline: 3px solid rgba(231, 76, 60, 0.2);
}

.jack-black {
  outline: 3px solid rgba(20, 25, 35, 0.25);
}

/* LCD Display */
.lcd {
  position: relative;
  border-radius: 10px;
  padding: 14px 12px;
  background: linear-gradient(180deg, rgba(214, 232, 210, 0.95), rgba(182, 210, 178, 0.92));
  border: 1px solid rgba(255, 255, 255, 0.18);
  box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.18), inset 0 -2px 10px rgba(255, 255, 255, 0.18);
  overflow: hidden;
}

.lcd::before {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    180deg,
    rgba(0, 0, 0, 0.05),
    rgba(0, 0, 0, 0.05) 1px,
    rgba(255, 255, 255, 0) 1px,
    rgba(255, 255, 255, 0) 4px
  );
  opacity: 0.28;
  pointer-events: none;
}

.lcd::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(
    circle at 20% 20%,
    rgba(255, 255, 255, 0.35),
    rgba(255, 255, 255, 0) 55%
  );
  opacity: 0.55;
  pointer-events: none;
}

.lcd-live {
  position: relative;
  z-index: 2;
  display: flex;
  justify-content: center;
  align-items: baseline;
  gap: 10px;
}

.lcd-value {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, 'Liberation Mono', monospace;
  font-variant-numeric: tabular-nums;
  font-weight: 900;
  font-size: 40px;
  letter-spacing: 1px;
  color: rgba(10, 22, 14, 0.95);
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.22);
}

.lcd-unit {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, 'Liberation Mono', monospace;
  font-weight: 900;
  font-size: 16px;
  color: rgba(10, 22, 14, 0.8);
}

/* Responsive */
@media (min-width: 768px) {
  body {
    padding: 24px;
  }

  .container {
    padding: 0;
  }

  .cols {
    flex-direction: row;
  }

  .sim-area {
    flex: 2;
    margin-right: 24px;
  }

  .controls {
    flex: 1;
  }

  .page-title {
    font-size: 32px;
  }
}

@media (max-width: 767px) {
  .header-grid {
    grid-template-columns: 1fr;
    grid-auto-flow: row;
    text-align: left;
  }

  .page-title {
    justify-self: start;
    font-size: 24px;
  }

  .header-actions {
    justify-self: start;
    width: 100%;
    margin-top: 8px;
  }

  .container {
    padding: 0 12px;
  }

  body {
    padding: 8px;
  }

  .btn {
    padding: 14px 20px;
    font-size: 16px;
    min-height: 48px;
  }

  /* Larger sliders for touch */
  input[type='range']::-webkit-slider-thumb {
    width: 24px;
    height: 24px;
    margin-top: -9px;
  }

  input[type='range']::-moz-range-thumb {
    width: 24px;
    height: 24px;
  }

  input[type='range'] {
    height: 10px;
  }

  .meter {
    left: 24px;
    right: 24px;
    top: 190px;
    width: auto;
  }

  .ldr-block {
    width: 170px;
    height: 145px;
  }
}

/* Touch device improvements */
@media (hover: none) and (pointer: coarse) {
  .btn {
    min-height: 50px;
    font-size: 17px;
  }

  .control-group {
    margin-bottom: 20px;
  }

  .button-stack {
    gap: 12px;
  }
}