@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;500;600&family=IBM+Plex+Mono:wght@400;500&display=swap");

:root {
  --primary-bg: #f2f2f2;
  --secondary-bg: #fafafa;
  --accent-primary: #5a5a5a;
  --accent-secondary: #767676;
  --text-primary: #2f2f2f;
  --text-secondary: #7a7a7a;
  --border-color: #d2d2d2;
  --slider-track: #e6e6e6;
  --ruler-line: #b2b2b2;
  --centerline: #7d7d7d;
}

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

body {
  font-family: "IBM Plex Sans", sans-serif;
  background: var(--primary-bg);
  color: var(--text-primary);
  min-height: 100vh;
  padding: 20px;
  overflow-x: hidden;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
}

header {
  text-align: center;
  margin-bottom: 40px;
  padding-bottom: 20px;
  border-bottom: 3px solid var(--accent-primary);
}

h1 {
  font-family: "IBM Plex Sans", sans-serif;
  font-weight: 600;
  font-size: 2.2rem;
  color: var(--accent-primary);
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}

.subtitle {
  font-size: 0.9rem;
  color: var(--text-secondary);
  letter-spacing: 1px;
  text-transform: uppercase;
  font-weight: 500;
}

.calculator-body {
  background: var(--secondary-bg);
  border-radius: 8px;
  padding: 35px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  border: 1px solid var(--border-color);
}

.slider-wheel {
  margin-bottom: 20px;
  position: relative;
}

.wheel-header {
  display: flex;
  justify-content: flex-start;
  align-items: baseline;
  margin-bottom: 10px;
}

.wheel-label {
  font-family: "IBM Plex Sans", sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--accent-primary);
}

.ruler-container {
  position: relative;
  height: 60px;
  background: var(--slider-track);
  border-radius: 4px;
  overflow: hidden;
  border: 1px solid var(--border-color);
  cursor: grab;
  user-select: none;
  touch-action: none;
}

.ruler-container.split-scale::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 1px;
  background: var(--border-color);
  z-index: 5;
  pointer-events: none;
}

.split-edge-fade {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 150px;
  pointer-events: none;
  z-index: 15;
}

.split-edge-fade.left {
  left: 0;
  background: linear-gradient(
    to right,
    var(--slider-track) 0,
    var(--slider-track) 96px,
    transparent 150px
  );
}

.split-edge-fade.right {
  right: 0;
  background: linear-gradient(
    to left,
    var(--slider-track) 0,
    var(--slider-track) 96px,
    transparent 150px
  );
}

.ruler-container:active {
  cursor: grabbing;
}

.ruler-container:focus-visible {
  outline: 3px solid rgba(90, 90, 90, 0.3);
  outline-offset: 2px;
}

.scale-edge-label {
  position: absolute;
  z-index: 20;
  font-size: 0.62rem;
  letter-spacing: 0.4px;
  text-transform: uppercase;
  color: var(--text-secondary);
  pointer-events: none;
}

.scale-edge-label.metric-edge {
  top: 2px;
  left: 6px;
}

.scale-edge-label.imperial-edge {
  bottom: 2px;
  right: 6px;
}

.readouts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 4px 12px;
  margin-bottom: 16px;
  padding: 10px 12px;
  background: var(--slider-track);
  border: 1px solid var(--border-color);
  border-radius: 4px;
}

.readout-item {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
  background: transparent;
  border: 0;
  border-radius: 0;
  padding: 1px 0;
  min-width: 0;
}

.readout-label {
  display: inline;
  font-size: 0.64rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.4px;
  margin-bottom: 0;
}

.readout-value {
  display: inline;
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.78rem;
  color: var(--text-primary);
  text-align: right;
}

.readout-divider {
  grid-column: 1 / -1;
  margin: 6px 0 4px;
  border-top: 1px solid var(--border-color);
}

.ruler-track {
  position: absolute;
  top: 0;
  height: 100%;
  display: flex;
  align-items: center;
  transition: left 0.1s ease-out;
  will-change: left;
}

.ruler-marks {
  display: flex;
  height: 100%;
  position: relative;
}

.ruler-mark {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  width: 1px;
}

.ruler-mark .tick {
  width: 1px;
  background: var(--ruler-line);
}

.ruler-mark.dual-mark {
  position: absolute;
  top: 0;
  height: 100%;
  width: 1px;
}

.ruler-mark.dual-mark .tick {
  position: absolute;
  left: 0;
}

.ruler-mark.dual-mark.metric-mark .tick {
  bottom: 50%;
}

.ruler-mark.dual-mark.imperial-mark .tick {
  top: 50%;
}

.ruler-mark.dual-mark.major.metric-mark .tick,
.ruler-mark.dual-mark.major.imperial-mark .tick {
  height: 18px;
}

.ruler-mark.dual-mark.minor.metric-mark .tick,
.ruler-mark.dual-mark.minor.imperial-mark .tick {
  height: 12px;
}

.ruler-mark.dual-mark.tick-only.metric-mark .tick,
.ruler-mark.dual-mark.tick-only.imperial-mark .tick {
  height: 8px;
}

.ruler-mark.major .tick {
  height: 30px;
  background: var(--text-primary);
  opacity: 0.6;
}

.ruler-mark.minor .tick {
  height: 20px;
  opacity: 0.5;
  background: var(--text-primary);
}

.ruler-mark.tick-only .tick {
  height: 12px;
  opacity: 0.4;
  background: var(--ruler-line);
}

.ruler-mark .label-metric,
.ruler-mark .label-imperial {
  position: absolute;
  font-size: 0.65rem;
  color: var(--text-primary);
  white-space: nowrap;
  font-family: "IBM Plex Mono", monospace;
  font-weight: 400;
  left: 50%;
  transform: translateX(-50%);
}

.ruler-mark .label-metric {
  top: 2px;
}

.ruler-mark .label-imperial {
  bottom: 2px;
}

.ruler-mark.major .label-metric {
  top: 0;
}

.ruler-mark.minor .label-metric {
  top: 3px;
}

.ruler-mark.tick-only .label-metric {
  top: 6px;
}

.ruler-mark.major .label-imperial {
  bottom: 0;
}

.ruler-mark.minor .label-imperial {
  bottom: 3px;
}

.ruler-mark.tick-only .label-imperial {
  bottom: 6px;
}

.ruler-mark.dual-mark.major.metric-mark .label-metric {
  top: 0;
}

.ruler-mark.dual-mark.minor.metric-mark .label-metric {
  top: 5px;
}

.ruler-mark.dual-mark.major.imperial-mark .label-imperial {
  bottom: 0;
}

.ruler-mark.dual-mark.minor.imperial-mark .label-imperial {
  bottom: 5px;
}

.ruler-mark.minor .label-metric,
.ruler-mark.minor .label-imperial {
  font-size: 0.5rem;
}

.ruler-mark.major .label-metric,
.ruler-mark.major .label-imperial {
  font-weight: 500;
}

.centerline {
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--centerline);
  transform: translateX(-50%);
  pointer-events: none;
  z-index: 10;
}

.centerline::before,
.centerline::after {
  content: "";
  position: absolute;
  left: 50%;
  width: 0;
  height: 0;
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
}

.centerline::before {
  top: -1px;
  border-top: 8px solid var(--centerline);
  transform: translateX(-50%);
}

.centerline::after {
  bottom: -1px;
  border-bottom: 8px solid var(--centerline);
  transform: translateX(-50%);
}

.sub-slider {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--border-color);
}

.sub-slider .wheel-label {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.sub-slider .ruler-container {
  height: 60px;
}

select {
  width: 100%;
  padding: 14px 16px;
  background: var(--slider-track);
  border: 2px solid var(--border-color);
  border-radius: 4px;
  color: var(--text-primary);
  font-family: "IBM Plex Sans", sans-serif;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  outline: none;
  transition: all 0.2s;
}

select:hover {
  border-color: var(--accent-primary);
}

select:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(90, 90, 90, 0.12);
}

option {
  background: var(--secondary-bg);
  color: var(--text-primary);
}

.material-buttons {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.material-btn {
  flex: 1;
  min-width: 120px;
  padding: 12px 20px;
  background: var(--slider-track);
  border: 2px solid var(--border-color);
  border-radius: 4px;
  color: var(--text-primary);
  font-family: "IBM Plex Sans", sans-serif;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}

.material-btn:hover {
  border-color: var(--accent-primary);
  background: #dddddd;
}

.material-btn.active {
  background: var(--accent-primary);
  color: white;
  border-color: var(--accent-primary);
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
  transform: translateY(1px);
}

.coarse-slider {
  height: 20px;
  background: var(--slider-track);
  border: 1px solid var(--border-color);
  border-radius: 4px 4px 0 0;
  position: relative;
  cursor: pointer;
  margin-bottom: -1px;
}

.coarse-slider-thumb {
  position: absolute;
  top: 50%;
  width: 40px;
  height: 16px;
  background: var(--accent-secondary);
  border: 1px solid var(--border-color);
  border-radius: 3px;
  transform: translate(-50%, -50%);
  cursor: grab;
  transition: background 0.2s;
}

.coarse-slider-thumb:hover {
  background: #676d74;
}

.coarse-slider-thumb:active {
  cursor: grabbing;
}

.adjustment-label {
  color: var(--accent-secondary);
}

footer {
  text-align: center;
  margin-top: 40px;
  padding: 20px;
  font-size: 0.8rem;
  color: var(--text-secondary);
  border-top: 1px solid var(--border-color);
}

@media (max-width: 768px) {
  h1 {
    font-size: 1.8rem;
  }

  .calculator-body {
    padding: 25px 20px;
  }

  .ruler-container {
    height: 60px;
  }

  .sub-slider .ruler-container {
    height: 60px;
  }

  .readouts {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2px 10px;
    margin-bottom: 14px;
    padding: 8px 10px;
    background: var(--slider-track);
    border: 1px solid var(--border-color);
    border-radius: 4px;
  }

  .readout-item {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 6px;
    background: transparent;
    border: 0;
    border-radius: 0;
    padding: 1px 0;
    min-width: 0;
  }

  .readout-label {
    display: inline;
    font-size: 0.58rem;
    margin-bottom: 0;
    letter-spacing: 0.35px;
  }

  .readout-value {
    display: inline;
    font-size: 0.72rem;
    text-align: right;
  }

  .readout-divider {
    margin: 3px 0 2px;
  }

  .material-buttons {
    gap: 6px;
  }

  .material-btn {
    flex: 1 1 calc(50% - 3px);
    min-width: 0;
    padding: 8px;
    font-size: 0.75rem;
    border-width: 1px;
  }

  .scale-edge-label {
    font-size: 0.52rem;
    letter-spacing: 0.2px;
  }

  .scale-edge-label.metric-edge {
    top: 1px;
    left: 4px;
  }

  .scale-edge-label.imperial-edge {
    bottom: 1px;
    right: 4px;
  }

  .split-edge-fade {
    width: 70px;
  }

  .split-edge-fade.left {
    background: linear-gradient(
      to right,
      var(--slider-track) 0,
      var(--slider-track) 36px,
      transparent 70px
    );
  }

  .split-edge-fade.right {
    background: linear-gradient(
      to left,
      var(--slider-track) 0,
      var(--slider-track) 36px,
      transparent 70px
    );
  }
}