.register-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  background: #fff;
  border-radius: 18px;
  box-shadow: 0 2px 24px rgba(44,62,80,0.05);
  padding: 40px 32px;
  width: fit-content;     /* cresce conforme o conteúdo */
  min-width: 700px;       /* mantém largura mínima confortável */
  margin: 40px auto;
  box-sizing: border-box;
}

form {
  width: 100%;
}

.form-columns {
  display: flex;
  gap: 24px;
  margin-bottom: 16px;
  width: 100%;
}

.input-group {
  flex: 1 1 0;
  display: flex;
  align-items: center;
  background: #F2F4F7;
  border-radius: 8px;
  padding: 0 18px;
  height: 52px;
  min-width: 200px;      /* mantém campo largo */
}

.input-icon {
  margin-right: 12px;
  color: #283648;
  display: flex;
  align-items: center;
}

input[type="text"],
input[type="email"],
input[type="password"] {
  background: transparent;
  border: none;
  outline: none;
  font-size: 1rem;
  width: 100%;
  color: #2d384d;
}

.register-btn {
  width: 100%;
  height: 48px;
  margin-top: 22px;
  background: #2c3e50;
  color: #fff;
  font-size: 1rem;
  border-radius: 8px;
  border: none;
  cursor: pointer;
}