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

body {
  font-family: 'Segoe UI', sans-serif;
  background-color: #0f1117;
  color: #e0e0e0;
  padding: 2.5rem;
  min-height: 100vh;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  color: #ffffff;
  letter-spacing: -0.5px;
  margin-bottom: 0.3rem;
}

h1 span {
  color: #4a9eff;
}

p {
  color: #888;
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

/* ONGLETS */
.tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
  border-bottom: 1px solid #222;
  padding-bottom: 1rem;
}

.tab {
  padding: 8px 18px;
  border-radius: 6px;
  border: 1px solid #2a2a2a;
  background: transparent;
  color: #888;
  cursor: pointer;
  font-size: 0.88rem;
  font-weight: 500;
  transition: all 0.2s;
  letter-spacing: 0.3px;
}

.tab:hover {
  border-color: #444;
  color: #ccc;
  background: #1a1a1a;
}

.tab.active {
  background: #1a2a3a;
  border-color: #4a9eff;
  color: #4a9eff;
}

/* SECTIONS */
.section { display: none; }
.section.active { display: block; }

.section-title {
  font-size: 1rem;
  font-weight: 600;
  color: #ffffff;
  padding-bottom: 0.8rem;
  border-bottom: 1px solid #1e1e1e;
  margin-bottom: 1.5rem;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  font-size: 0.85rem;
}

/* FORMULE BOX */
.formula-box {
  background: #13181f;
  border: 1px solid #1e2a3a;
  border-left: 3px solid #4a9eff;
  border-radius: 8px;
  padding: 12px 16px;
  font-size: 0.88rem;
  color: #888;
  margin-bottom: 1.5rem;
  font-family: 'Courier New', monospace;
}

.formula-box strong {
  color: #4a9eff;
}

/* INPUTS */
.inputs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
  margin-bottom: 1.5rem;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.input-group label {
  font-size: 0.78rem;
  color: #777;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-weight: 500;
}

.input-group input {
  background: #13181f;
  border: 1px solid #222;
  border-radius: 6px;
  padding: 10px 12px;
  color: #ffffff;
  font-size: 0.95rem;
  transition: border-color 0.2s;
}

.input-group input:focus {
  outline: none;
  border-color: #4a9eff;
  background: #141c24;
}

.input-group .unit {
  font-size: 0.72rem;
  color: #444;
}

/* BOUTON */
.calc-btn {
  padding: 10px 22px;
  background: #1a2a3a;
  border: 1px solid #4a9eff;
  border-radius: 6px;
  color: #4a9eff;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  margin-bottom: 1.5rem;
  transition: all 0.2s;
  letter-spacing: 0.3px;
}

.calc-btn:hover {
  background: #4a9eff;
  color: #0f1117;
}

/* RÉSULTATS */
.results-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
}

.kpi-card {
  background: #13181f;
  border: 1px solid #1e1e1e;
  border-radius: 10px;
  padding: 14px 16px;
  transition: border-color 0.2s;
}

.kpi-card:hover {
  border-color: #2a2a2a;
}

.kpi-label {
  font-size: 0.72rem;
  color: #555;
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.kpi-value {
  font-size: 1.5rem;
  font-weight: 600;
  color: #ffffff;
  margin-bottom: 4px;
}

.kpi-value.good { color: #22c55e; }
.kpi-value.warn { color: #f59e0b; }
.kpi-value.bad  { color: #ef4444; }

.kpi-bench {
  font-size: 0.7rem;
  color: #444;
}

.hidden { display: none; }