Html – Cant align buttons in CSS

body {
  background-color: #6A6E64;
  font-family: Helvetica, Arial, sans-serif;
  color: white;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

.question-container {
  margin-bottom: 1rem;
}

.navigation {
  display: flex;
  justify-content: space-between;
}

button {
  background-color: #393D32;
  color: white;
  border: none;
  border-radius: 25px;
  padding: 0.5rem 1rem;
  cursor: pointer;
  font-size: 1rem;
  transition: background-color 0.3s ease, transform 0.3s ease;
}

button:hover {
  background-color: #2B2E23;
  transform: scale(1.05);
}

button.share {
  margin-top: 1rem;
  display: none;
  /* hide the share button by default */
}

.copy-message {
  font-size: 0.9rem;
  margin-top: 0.5rem;
}

.start-screen {
  text-align: center;
}

.question-container,
.navigation {
  display: none;
}

.option {
  display: block;
  margin-bottom: 1rem;
}

.options-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.option {
  flex: 1;
  margin: 0 0.5rem;
  box-sizing: border-box;
  text-align: center;
  padding: 10px;
}

.result-content {
  text-align: center;
  margin-bottom: 1rem;
}

.results-container {
  display: none;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  margin-top: 20px;
  text-align: center;
}

.hidden {
  display: none;
}

button.previous {
  display: flex;
}

.restart-quiz {
  display: none;
  /* hide the restart button by default */
}


/* show the share and restart buttons only on the results page */

.results-container .share {
  display: inline-block;
}

.results-container .restart-quiz {
  display: inline-block;
}

.button-container {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

button.restart-quiz,
button.share {
  min-height: 40px;
  /* You can adjust the value according to your desired height */
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1.2;
  /* Add this line */
}


/* Hide the share and restart buttons on the question pages */

.navigation {
  display: none;
}


/* Show the share and restart buttons on the results page */

.results-container .share-container {
  display: flex;
}

.results-container button.restart-quiz,
.results-container button.share {
  display: inline-block;
}

button {
  font-size: 1rem;
  /* Adjust the font-size of all buttons */
  padding: 0.5rem 1rem;
  /* Adjust the padding of all buttons */
}

button.restart-quiz,
button.share {
  font-size: 1rem;
  /* Adjust the font-size of restart and share buttons to match other buttons */
  padding: 0.5rem 1rem;
  /* Adjust the padding of restart and share buttons to match other buttons */
}

<div class="quiz-container">
  <!-- Add this new div inside the quiz-container div -->
  <div class="start-screen">
    <h1>Find Your Learning Style</h1>
    <button class="start-quiz">Start Quiz</button>
  </div>

  <div class="question-container">
    <!-- Question template -->
  </div>
  <div class="navigation">
    <button class="previous">Previous Question</button>
  </div>
</div>
<div class="results-container">
  <h2>Your learning style is:</h2>
  <h1 class="results-container-text"></h1>
  <div class="percentage-container">
    <!-- Percentage results template -->
  </div>
  <div class="button-container">
    <button class="restart-quiz">Restart Quiz</button>
    <button class="share">Share Quiz</button>
    <div class="copy-message hidden">Quiz URL copied to clipboard</div>
  </div>
</div>