JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
  <button class="child">button</button>
  <button class="child">button</button>
</div>

<div class="grid">
  <h1>Subscribe to this form</h1>
  <label>
    <input type="text"/> Name
  </label>
  <label>
    <input type="text"/> Email
  </label>
  <button>Subscribe</button>
</div>

CSS

h1 {
  all: initial;
  font-family: Arial;
  font-size: 18px;
  font-weight: bold;
}

button {
  font-size: 16px;
  padding: 10px;
  border-radius: 4px;
  border: 0;
  color: white;
  background-color: #03a9f4;
}

label {
  font-family: Arial;
  font-size: 18px;
  color: gray;
}

input {
  font-size: 16px;
  margin-right: 10px;
  border: 0;
  border-radius: 4px;
  padding: 10px;
}

.parent {
  display: flex;
  flex-direction: column;
  
  padding: 10px;
  border: 1px solid gray;
  border-radius: 4px;
}

.child {
  margin: 5px;
}

@media (min-width: 500px) {
  .parent {
    flex-direction: initial;
  }
}

.child {
  display: block;
}

/* grid */
.grid {
  display: grid;
  grid-gap: 10px 20px;
  grid-template-columns: 1fr;
  grid-template-rows: auto 1fr 1fr auto;
  grid-template-areas: 
    'header'
    'none'
    'none'
    'button'
  ;
  margin-top: 10px;
  padding: 10px;
  border: 1px solid gray;
  border-radius: 4px;
}

@media (min-width: 500px) {
  .grid {
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto 1fr auto;
    grid-template-areas: 
      'header header'
      'none none'
      'button button'
    ;
  }
}

.grid h1 {
  text-align: center;
  grid-area: header;
}

.grid label {
  display: flex;
  align-items: center;
}

.grid input {
  flex-grow: 1;
  margin-right: 10px;
}

.grid button {
  background-color: #03a9f4;
  grid-column-start: 1;
  grid-column-end: span 2;
  grid-area: button;
}