@import url('https://fonts.googleapis.com/css2?family=Share+Tech+Mono&family=Barlow+Condensed:wght@400;600;700;900&display=swap');

:root {
  --bg: #0a0a0a;
  --panel: #141414;
  --panel2: #1a1a1a;
  --border: #272727;
  --accent: #e8a000;
  --accent2: #ff6b2b;
  --text: #d0d0d0;
  --muted: #505050;
  --success: #4caf50;
  --mono: 'Share Tech Mono', monospace;
  --head: 'Barlow Condensed', sans-serif;
  --nav-h: 60px;
  --tab-h: 52px;
}

* { box-sizing: border-box; margin: 0; padding: 0; -webkit-tap-highlight-color: transparent; }

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
  font-size: 14px;
  overscroll-behavior: none;
}

/* ── GRID BACKGROUND ── */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    repeating-linear-gradient(0deg, transparent, transparent 39px, #141414 39px, #141414 40px),
    repeating-linear-gradient(90deg, transparent, transparent 39px, #141414 39px, #141414 40px);
  pointer-events: none;
  z-index: 0;
}

/* ── TOP NAV ── */
.top-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  background: #0f0f0f;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 16px;
  z-index: 100;
  gap: 12px;
}

.nav-logo {
  font-family: var(--head);
  font-weight: 900;
  font-size: 22px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: #fff;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-logo .dot {
  width: 10px; height: 10px;
  background: var(--accent);
  display: inline-block;
}

.nav-badge {
  margin-left: auto;
  font-size: 9px;
  letter-spacing: 2px;
  color: var(--muted);
  text-transform: uppercase;
  border: 1px solid var(--border);
  padding: 3px 8px;
}

/* ── BOTTOM TAB BAR ── */
.tab-bar {
  position: fixed;
  bottom: 0; left: 0; right: 0;
  height: var(--tab-h);
  background: #0f0f0f;
  border-top: 1px solid var(--border);
  display: flex;
  z-index: 100;
}

.tab-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  text-decoration: none;
  color: var(--muted);
  font-size: 9px;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  font-family: var(--head);
  font-weight: 700;
  transition: color 0.2s;
  border-top: 2px solid transparent;
  padding-top: 2px;
}

.tab-item svg { width: 20px; height: 20px; stroke: currentColor; fill: none; stroke-width: 1.8; }
.tab-item.active { color: var(--accent); border-top-color: var(--accent); }
.tab-item:hover { color: var(--text); }

/* ── PAGE WRAPPER ── */
.page {
  position: relative;
  z-index: 1;
  padding: calc(var(--nav-h) + 20px) 16px calc(var(--tab-h) + 24px);
  max-width: 720px;
  margin: 0 auto;
  min-height: 100vh;
}

/* ── PAGE HEADER ── */
.page-header {
  border-left: 4px solid var(--accent);
  padding-left: 14px;
  margin-bottom: 24px;
}
.page-header .eyebrow {
  font-size: 10px;
  letter-spacing: 3px;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 4px;
}
.page-header h1 {
  font-family: var(--head);
  font-size: 38px;
  font-weight: 900;
  text-transform: uppercase;
  color: #fff;
  line-height: 1;
  letter-spacing: 1px;
}
.page-header p {
  margin-top: 5px;
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 1px;
}

/* ── CARDS ── */
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  margin-bottom: 14px;
}
.card-header {
  background: var(--panel2);
  border-bottom: 1px solid var(--border);
  padding: 9px 14px;
  font-family: var(--head);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--accent);
  display: flex;
  align-items: center;
  gap: 8px;
}
.card-header::before {
  content: '';
  width: 7px; height: 7px;
  background: var(--accent);
  flex-shrink: 0;
}
.card-body { padding: 16px; }

/* ── FORM ELEMENTS ── */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; }

.field { display: flex; flex-direction: column; gap: 5px; }
.field.full { grid-column: 1 / -1; }

label {
  font-size: 9px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--muted);
}

select, input[type="number"], input[type="text"] {
  background: var(--bg);
  border: 1px solid #2e2e2e;
  color: var(--text);
  font-family: var(--mono);
  font-size: 14px;
  padding: 9px 11px;
  width: 100%;
  outline: none;
  transition: border-color 0.2s;
  -webkit-appearance: none;
  appearance: none;
  border-radius: 0;
}
select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='10' viewBox='0 0 10 10'%3E%3Cpath fill='%23e8a000' d='M5 7L0 2h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  padding-right: 28px;
  cursor: pointer;
}
select option { background: #1a1a1a; }
select:focus, input:focus { border-color: var(--accent); }

.unit-hint {
  font-size: 10px;
  color: var(--muted);
  text-align: right;
  margin-top: 2px;
}

/* ── BUTTONS ── */
.btn-calc {
  width: 100%;
  background: var(--accent);
  color: #000;
  border: none;
  font-family: var(--head);
  font-size: 17px;
  font-weight: 900;
  letter-spacing: 4px;
  text-transform: uppercase;
  padding: 14px;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
  margin-top: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}
.btn-calc:hover { background: #ffb800; }
.btn-calc:active { transform: scale(0.99); background: var(--accent2); }

.btn-reset {
  width: 100%;
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border);
  font-family: var(--head);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 3px;
  text-transform: uppercase;
  padding: 10px;
  cursor: pointer;
  transition: all 0.15s;
  margin-top: 6px;
}
.btn-reset:hover { color: var(--text); border-color: var(--muted); }

/* ── RESULTS GRID ── */
.results-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
  background: #1e1e1e;
  border: 1px solid var(--border);
  margin-top: 14px;
  overflow: hidden;
}
.result-item {
  background: var(--panel);
  padding: 16px 14px;
  position: relative;
  border-left: 3px solid transparent;
  transition: border-color 0.3s;
}
.result-item.wide { grid-column: 1 / -1; }
.result-item.lit { border-left-color: var(--accent); }

.result-label {
  font-size: 9px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 6px;
}
.result-value {
  font-family: var(--head);
  font-size: 32px;
  font-weight: 900;
  color: #fff;
  line-height: 1;
  transition: color 0.3s;
}
.result-item.lit .result-value { color: var(--accent); }
.result-unit {
  font-size: 10px;
  color: var(--muted);
  margin-top: 3px;
}

/* ── NOTE BAR ── */
.note-bar {
  border: 1px solid var(--border);
  border-top: 2px solid var(--accent2);
  background: var(--panel);
  padding: 11px 14px;
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 0.5px;
  margin-top: 14px;
  line-height: 1.7;
}
.note-bar strong { color: var(--accent2); }

/* ── TABLE ── */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 12px;
}
.data-table th {
  font-family: var(--head);
  font-size: 10px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent);
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  background: var(--panel2);
}
.data-table td {
  padding: 9px 10px;
  border-bottom: 1px solid #1e1e1e;
  color: var(--text);
  font-family: var(--mono);
}
.data-table tr:last-child td { border-bottom: none; }
.data-table tr:hover td { background: #181818; }
.data-table td.highlight {
  color: var(--accent);
  font-weight: bold;
}

/* ── HIDDEN ── */
.hidden { display: none !important; }

/* ── FLASH ANIMATION ── */
@keyframes flash-in {
  0%   { background: #221a00; }
  100% { background: var(--panel); }
}
.flash { animation: flash-in 0.5s ease forwards; }

/* ── RESPONSIVE ── */
@media (max-width: 480px) {
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .result-value { font-size: 26px; }
  .page-header h1 { font-size: 30px; }
}