.tool-main-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: 1.25rem;
  max-width: 440px;
  margin: 0 auto;
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  box-shadow: var(--shadow-base);
  position: relative;
  overflow: hidden;
}

.tach-panel {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  position: relative;
  z-index: 1;
}

.panel-section {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-base);
  opacity: 0.7;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.preset-select {
  width: 100%;
  padding: 0.65rem 0.75rem;
  background: var(--bg-page);
  border: 1px solid var(--border-base);
  border-radius: 0.75rem;
  color: var(--text-base);
  font-size: 0.875rem;
  cursor: pointer;
  transition: border-color 0.2s;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24'%3E%3Cpath fill='%23888' d='M7 10l5 5 5-5z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  padding-right: 2rem;
}

.preset-select:focus {
  outline: none;
  border-color: var(--accent);
}

.stepper-wrap {
  display: flex;
  align-items: center;
  background: var(--bg-page);
  border: 1px solid var(--border-base);
  border-radius: 0.75rem;
  overflow: hidden;
  transition: border-color 0.2s;
}

.stepper-wrap:focus-within {
  border-color: var(--accent);
}

.stepper-input {
  width: 100%;
  padding: 0.6rem 0.25rem;
  border: none;
  background: transparent;
  color: var(--text-base);
  font-size: 0.875rem;
  text-align: center;
  font-variant-numeric: tabular-nums;
  box-sizing: border-box;
  -moz-appearance: textfield;
}

.stepper-input::-webkit-inner-spin-button,
.stepper-input::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.stepper-input:focus {
  outline: none;
}

.stepper-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 3rem;
  padding: 0.5rem;
  border: none;
  background: transparent;
  color: var(--text-base);
  opacity: 0.5;
  font-size: 0.75rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s ease;
  user-select: none;
}

.stepper-btn:hover {
  background: var(--bg-page);
  color: var(--accent);
  opacity: 1;
}

.stepper-btn:active {
  background: var(--border-base);
  transform: scale(0.95);
}

.tach-visual {
  position: relative;
  width: 240px;
  height: 240px;
  margin: 0 auto;
}

.tach-svg {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.tach-bezel-bg {
  fill: url("#bezel-grad");
  stroke: var(--border-base);
  stroke-width: 1;
}

.tach-bezel-outer {
  fill: none;
  stroke: var(--border-color);
  stroke-width: 2;
}

.tach-bezel-inner {
  fill: none;
  stroke: var(--border-base);
  stroke-width: 1;
}

.tach-dial {
  fill: url("#dial-grad");
  stroke: var(--border-color);
  stroke-width: 1;
}

.tick-major {
  stroke: var(--text-base);
  stroke-width: 2;
  stroke-linecap: round;
  opacity: 0.65;
}

.tick-minor {
  stroke: var(--text-base);
  stroke-width: 1;
  stroke-linecap: round;
  opacity: 0.3;
}

.tick-label-line {
  opacity: 0.85;
}

.tick-label {
  font-size: 6px;
  font-weight: 700;
  fill: var(--text-base);
  opacity: 0.75;
}

.tach-hand-group {
  transform-origin: 110px 110px;
  transition: transform 0.6s cubic-bezier(0.22, 1, 0.36, 1);
}

.tach-hand {
  stroke: var(--accent);
  stroke-width: 2.5;
  stroke-linecap: round;
}

.tach-hand-tail {
  stroke: var(--accent);
  stroke-width: 1.5;
  stroke-linecap: round;
  opacity: 0.3;
}

.tach-pip {
  fill: var(--accent);
}

.tach-pip-ring {
  fill: none;
  stroke: var(--accent);
  stroke-width: 1.5;
  opacity: 0.4;
}

.tach-sweep {
  fill: none;
  stroke: var(--accent);
  stroke-width: 3;
  stroke-linecap: round;
  opacity: 0.35;
  filter: url("#glow");
}

.tach-time-label {
  font-size: 11px;
  font-weight: 800;
  fill: var(--text-base);
  letter-spacing: 0.02em;
  font-variant-numeric: tabular-nums;
  opacity: 0.85;
}

.tach-speed-label {
  font-size: 20px;
  font-weight: 900;
  fill: var(--accent);
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  transition: fill 0.4s ease;
}

.tach-unit-label {
  font-size: 7px;
  font-weight: 600;
  fill: var(--text-base);
  opacity: 0.5;
  letter-spacing: 0.08em;
}

.tach-glow {
  fill: var(--accent);
  opacity: 0.5;
  animation: pulse-glow 1.5s ease-in-out infinite;
  transform-origin: center;
}

.tach-glow-ring {
  fill: none;
  stroke: var(--accent);
  stroke-width: 2;
  opacity: 0.5;
  animation: pulse-ring 1.5s ease-in-out infinite;
  transform-origin: center;
}

@keyframes pulse-glow {
  0%, 100% { opacity: 0.25; }
  50% { opacity: 0.6; }
}

@keyframes pulse-ring {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 0.6; }
}

.tach-readout {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  padding: 0.875rem 1rem;
  background: var(--bg-page);
  border: 1px solid var(--border-base);
  border-radius: 1rem;
}

.readout-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
}

.readout-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: -0.03em;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  transition: color 0.4s ease;
}

.readout-unit {
  font-size: 0.65rem;
  font-weight: 600;
  color: var(--text-base);
  opacity: 0.5;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.readout-label {
  font-size: 0.65rem;
  font-weight: 600;
  color: var(--text-base);
  opacity: 0.5;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.readout-bezel {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-base);
  font-variant-numeric: tabular-nums;
}

.readout-divider {
  width: 1px;
  height: 2.5rem;
  background: var(--border-base);
  flex-shrink: 0;
}

.speed-fast .tach-hand,
.speed-fast .tach-hand-tail {
  stroke: var(--color-red, #ef4444);
}

.speed-fast .tach-pip-ring {
  stroke: var(--color-red, #ef4444);
}

.speed-fast .tach-sweep,
.speed-fast .tach-glow,
.speed-fast .tach-glow-ring {
  stroke: var(--color-red, #ef4444);
}

.speed-fast .tach-glow {
  fill: var(--color-red, #ef4444);
}

.speed-fast .tach-speed-label {
  fill: var(--color-red, #ef4444);
}

.speed-fast .readout-value {
  color: var(--color-red, #ef4444);
}

.speed-mid .tach-hand,
.speed-mid .tach-hand-tail {
  stroke: var(--color-amber, #f59e0b);
}

.speed-mid .tach-pip-ring {
  stroke: var(--color-amber, #f59e0b);
}

.speed-mid .tach-sweep,
.speed-mid .tach-glow,
.speed-mid .tach-glow-ring {
  stroke: var(--color-amber, #f59e0b);
}

.speed-mid .tach-glow {
  fill: var(--color-amber, #f59e0b);
}

.speed-mid .tach-speed-label {
  fill: var(--color-amber, #f59e0b);
}

.speed-mid .readout-value {
  color: var(--color-amber, #f59e0b);
}

.speed-slow .tach-hand,
.speed-slow .tach-hand-tail {
  stroke: var(--color-green, #22c55e);
}

.speed-slow .tach-pip-ring {
  stroke: var(--color-green, #22c55e);
}

.speed-slow .tach-sweep,
.speed-slow .tach-glow,
.speed-slow .tach-glow-ring {
  stroke: var(--color-green, #22c55e);
}

.speed-slow .tach-glow {
  fill: var(--color-green, #22c55e);
}

.speed-slow .tach-speed-label {
  fill: var(--color-green, #22c55e);
}

.speed-slow .readout-value {
  color: var(--color-green, #22c55e);
}

.steps-section {
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
  padding: 1rem 1.125rem;
  background: var(--bg-page);
  border-radius: 0.875rem;
  border: 1px solid var(--border-base);
}

.step-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.step-marker {
  width: 1.375rem;
  height: 1.375rem;
  border-radius: 50%;
  background: var(--accent);
  color: var(--text-on-primary, #fff);
  font-size: 0.6875rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.step-text {
  font-size: 0.8125rem;
  color: var(--text-base);
  opacity: 0.85;
  line-height: 1.4;
}

.tip-row {
  display: flex;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  background: var(--bg-page);
  border-radius: 0.75rem;
  border: 1px solid var(--border-base);
}

.tip-icon {
  flex-shrink: 0;
  margin-top: 0.1rem;
  color: var(--accent);
}

.tip-text {
  font-size: 0.8rem;
  color: var(--text-base);
  opacity: 0.85;
  line-height: 1.5;
}

@media (max-width: 520px) {
  .tool-main-card {
    padding: 1rem;
    gap: 1rem;
  }

  .tach-visual {
    width: 200px;
    height: 200px;
  }

  .readout-value {
    font-size: 1.5rem;
  }
}