/* Linear-inspired dark system (DESIGN.md) — dark-only by design. */

:root {
  color-scheme: dark;
  --canvas: #010102;
  --surface-1: #0f1011;
  --surface-2: #141516;
  --surface-3: #18191a;
  --hairline: #23252a;
  --hairline-strong: #34343a;
  --ink: #f7f8f8;
  --ink-muted: #d0d6e0;
  --ink-subtle: #8a8f98;
  --ink-tertiary: #62666d;
  --primary: #5e6ad2;
  --primary-hover: #828fff;
  --primary-focus: #5e69d1;
  --on-primary: #ffffff;
  --gas-tint: rgba(94, 106, 210, 0.25);
  --focus-ring: rgba(94, 105, 209, 0.5);
  --success: #27a644;
  --danger: #ec5a54;
  --font-text: "Inter", "SF Pro Text", -apple-system, system-ui, "Segoe UI", Roboto, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", "Geist Mono", Menlo, monospace;
  --r-md: 8px;
  --r-lg: 12px;
  --r-pill: 9999px;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

body {
  margin: 0;
  font-family: var(--font-text);
  font-size: 15px;
  line-height: 1.5;
  background: var(--canvas);
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
}

::selection {
  background: rgba(94, 106, 210, 0.4);
}

/* --- Top nav --- */

.top-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  padding: 0 16px;
  background: rgba(1, 1, 2, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--hairline);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand img {
  display: block;
  border-radius: 6px;
}

.wordmark {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.2px;
}

.icon-btn {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  padding: 0;
  background: transparent;
  border: none;
  border-radius: var(--r-md);
  color: var(--ink-subtle);
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}

.icon-btn:hover {
  background: var(--surface-2);
  color: var(--ink);
}

/* --- Layout --- */

main {
  max-width: 30rem;
  margin: 0 auto;
  padding: 24px 16px 56px;
}

main > section {
  display: flex;
  flex-direction: column;
  gap: 32px;
  animation: view-in 0.18s ease-out;
}

@keyframes view-in {
  from {
    opacity: 0;
    transform: translateY(4px);
  }
}

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

.eyebrow {
  margin: 0;
  font-size: 13px;
  font-weight: 500;
  line-height: 1.3;
  letter-spacing: 0.4px;
  color: var(--ink-subtle);
}

.hero {
  padding-top: 16px;
}

.hero h2 {
  margin: 0;
  font-size: 26px;
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.6px;
}

.hero p {
  margin: 10px 0 0;
  color: var(--ink-subtle);
}

.view-title {
  margin: 0;
  font-size: 20px;
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.4px;
}

/* --- Cards --- */

.card {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 20px;
  background: var(--surface-1);
  border: 1px solid var(--hairline);
  border-radius: var(--r-lg);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.04);
}

.card h3 {
  margin: 0;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.2px;
}

.card p {
  margin: 0;
  font-size: 14px;
  color: var(--ink-subtle);
}

/* --- Tank gauge --- */

.gauge-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.gauge-volume {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 600;
  color: var(--ink);
}

.gauge-cap {
  font-size: 13px;
  font-weight: 400;
  color: var(--ink-subtle);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin: 0;
  padding: 3px 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  color: var(--ink-muted);
  background: var(--surface-2);
  border: 1px solid var(--hairline);
  border-radius: var(--r-pill);
}

.dot {
  width: 7px;
  height: 7px;
  border-radius: var(--r-pill);
  background: var(--success);
  box-shadow: 0 0 6px rgba(39, 166, 68, 0.6);
}

.gauge-track {
  position: relative;
  height: 14px;
  background: var(--canvas);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  overflow: hidden;
}

.gauge-fuel {
  height: 100%;
  width: 0;
  background: var(--gas-tint);
  transition: width 0.4s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.gauge-eth {
  height: 100%;
  width: 0;
  background: var(--primary);
  transition: width 0.4s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.gauge-tick {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--ink);
  opacity: 0.9;
  transition: left 0.4s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.gauge-legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 14px;
  margin: 0;
  font-size: 12px;
  color: var(--ink-subtle);
}

.gauge-legend > span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.swatch {
  width: 10px;
  height: 10px;
  border-radius: 3px;
}

.swatch-eth {
  background: var(--primary);
}

.swatch-gas {
  background: var(--gas-tint);
  border: 1px solid var(--hairline-strong);
}

.gauge-meta {
  margin-left: auto;
}

.num {
  font-family: var(--font-mono);
  color: var(--ink-muted);
}

/* --- Forms --- */

form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.field-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(0, 1fr));
  gap: 12px;
}

/* Keeps inputs aligned when a label wraps to more lines than its siblings. */
.field-row label input {
  margin-top: auto;
}

label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  color: var(--ink-subtle);
}

input {
  width: 100%;
  min-height: 44px;
  padding: 10px 12px;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--ink);
  background: var(--canvas);
  border: 1px solid var(--hairline-strong);
  border-radius: var(--r-md);
  transition: border-color 0.15s ease;
}

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

input[type="number"] {
  -moz-appearance: textfield;
  appearance: textfield;
}

input:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 0;
  border-color: var(--primary-focus);
}

/* --- Buttons --- */

button {
  min-height: 40px;
  padding: 10px 16px;
  font-family: var(--font-text);
  font-size: 14px;
  font-weight: 500;
  line-height: 1.2;
  color: var(--ink);
  background: var(--surface-2);
  border: 1px solid var(--hairline-strong);
  border-radius: var(--r-md);
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease;
}

button:hover {
  background: var(--surface-3);
}

button:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

button.primary {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--on-primary);
}

button.primary:hover {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
}

button.primary:active {
  background: var(--primary-focus);
  border-color: var(--primary-focus);
}

button.danger {
  background: transparent;
  color: var(--danger);
}

button.danger:hover {
  background: transparent;
  border-color: var(--danger);
}

.btn-row {
  display: flex;
  gap: 10px;
}

.btn-row button {
  flex: 1;
}

/* --- Messages --- */

.preview {
  margin: 0;
  font-size: 13px;
  color: var(--ink-muted);
}

.preview:empty {
  display: none;
}

.error {
  margin: 0;
  font-size: 13px;
  color: var(--danger);
}

/* --- Settings --- */

.danger-zone {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: flex-start;
  padding-top: 20px;
  border-top: 1px solid var(--hairline);
}

.danger-zone p {
  margin: 0;
  font-size: 13px;
  color: var(--ink-subtle);
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }
}