CSS - Borda

Cor

<!-- Head starts -->
<style>
  .border-text {
    border-color: rgb(7, 209, 64);
    border-style: solid;
  }
</style>
<!-- Style block end -->
<!-- Head ends -->
<!-- Body starts -->
<p class="border-text">Some text</p>
<!-- Body ends -->

Raio

<!-- index.html -->
<!-- Head starts -->
<style>
  .border-text {
    border-style: solid;
    border-radius: 10px;
    padding: 5px;
  }
</style>
<!-- Style block end -->
<!-- Head ends -->
<!-- Body starts -->
<p class="border-text">Some text</p>
<!-- Body ends -->

Arrendondada

<!-- Head starts -->
<style>
  .round-div-size {
    width: 200px;
    height: 200px;
  }

  .border {
    border-style: solid;
    border-radius: 50%;
  }
</style>
<!-- Style block end -->
<!-- Head ends -->
<!-- Body starts -->
<div class="border round-div-size"></div>
<!-- Body ends -->

Solida

<!-- Head starts -->
<style>
  .border-text {
    border-style: solid;
    padding: 5px;
  }
</style>
<!-- Style block end -->
<!-- Head ends -->
<!-- Body starts -->
<p class="border-text">Some text</p>
<!-- Body ends -->

Largura

<!-- Head starts -->
<style>
  .border-text {
    border-width: 10px;
    border-style: solid;
  }
</style>
<!-- Style block end -->
<!-- Head ends -->
<!-- Body starts -->
<p class="border-text">Some text</p>
<!-- Body ends -->