* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', sans-serif;
}

body {
  background: linear-gradient(135deg, #0f172a, #1e293b);
  color: #fff;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 20px;
  flex-direction: column;
}

.container {
  width: 100%;
  background: #1e293b;
  padding: 30px;
  border-radius: 16px;
  max-width: 420px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.4);
}

h1 {
  text-align: center;
  margin-bottom: 20px;
}

/* Tabs */
.tabs {
  display: flex;
  margin-bottom: 20px;
}

.tab {
  flex: 1;
  padding: 10px;
  text-align: center;
  cursor: pointer;
  background: #334155;
  border-radius: 8px;
  margin: 0 5px;
  transition: 0.2s;
}

.tab:hover {
  background: #475569;
}

.tab.active {
  background: #38bdf8;
  color: #0f172a;
  font-weight: bold;
}

/* Form */
.form-group {
  margin-bottom: 15px;
}

label {
  display: block;
  margin-bottom: 5px;
  font-size: 14px;
}

/* INPUT PADRÃO */
input, select {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid transparent;
  background: #334155;
  color: #fff;
  transition: 0.2s;
}

/* Foco bonito (UX) */
input:focus, select:focus {
  outline: none;
  border: 1px solid #38bdf8;
  background: #1e293b;
}

/* Placeholder */
input::placeholder {
  color: #94a3b8;
}

/* Layout inline */
.inline {
  display: flex;
  gap: 10px;
}

/* BOTÃO */
button {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 8px;
  background: #22c55e;
  color: white;
  font-size: 16px;
  cursor: pointer;
  transition: 0.2s;
}

button:hover {
  background: #16a34a;
  transform: scale(1.02);
}

/* RESULTADO */
.result {
  margin-top: 20px;
  padding: 15px;
  background: #0f172a;
  border-radius: 8px;
  text-align: center;
  font-size: 18px;
  line-height: 1.6;
}

/* Destaque no valor final */
.result div:last-child {
  font-size: 20px;
  color: #22c55e;
}

/* Footer */
footer {
  margin-top: 20px;
  font-size: 12px;
  color: #94a3b8;
}

/* RESPONSIVO */
@media (max-width: 480px) {
  .container {
    padding: 20px;
    border-radius: 12px;
  }

  h1 {
    font-size: 20px;
  }

  input, select {
    font-size: 14px;
    padding: 8px;
  }

  button {
    font-size: 14px;
    padding: 10px;
  }

  .inline {
    flex-direction: column;
  }

  .tabs {
    flex-direction: column;
    gap: 10px;
  }

  .tab {
    margin: 0;
  }

  .result {
    font-size: 16px;
  }
}