Layout With Flexbox

Would Love any and all feedback!

HTML:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="styles.css" />
    <link rel="import" href="./images/" />
    <title>Tea Cozy</title>
  </head>
  <body>
    <header>
      <img src="./images/img-tea-cozy-logo.png" alt="" />
      <ul>
        <li><a href="#">Mission</a></li>
        <li><a href="#">Featured Tea</a></li>
        <li><a href="#">Locations</a></li>
      </ul>
    </header>
    <section class="mission">
      <div class="mission_card">
      <h2>Our Mission</h2>
      <h4>
        Handpicked, Artisanally Curated, Free Range, Sustanible, Small Batch,
        Fair Trade, Organic Tea
      </h4>
      </div>
    </section>
    <section class="totm">
      <h2>Tea of the month</h2>
      <h4>What's Steeping at The Tea Cozy?</h4>
      <div class="totm_imgs">
        <div class="totm_img">
          <img src="images/img-berryblitz.jpg" alt="" />
          <h4>Fall Berry Blitz tea</h4>
        </div>
        <div class="totm_img">
          <img src="images/img-spiced-rum.jpg" alt="" />
          <h4>Spiced Rum tea</h4>
        </div>
        <div class="totm_img">
          <img src="images/img-donut.jpg" alt="" />
          <h4>Seasonal Donuts</h4>
        </div>
        <div class="totm_img">
          <img src="images/img-myrtle-ave.jpg" alt="" />
          <h4>Myrtle Ave Tea</h4>
        </div>
        <div class="totm_img">
          <img src="images/img-bedford-bizarre.jpg" alt="" />
          <h4>Bedford Bizarre Tea</h4>
        </div>
      </div>
    </section>
    <section class="locations">
      <div class="location_container">
        <h2>Locations</h2>
        <div class="location_card">
          <h3>Downtown</h3>
          <h4>384 West 4th St</h4>
          <h4>Suite 108</h4>
          <h4>Portland, Maine</h4>
        </div>
        <div class="location_card">
          <h3>East Bayside</h3>
          <h4>3433 Phisherman's Avenue</h4>
          <h4>(Northwest Corner)</h4>
          <h4>Portland, Maine</h4>
        </div>
        <div class="location_card">
          <h3>Oakdale</h3>
          <h4>515 Crescent Avenue</h4>
          <h4>Second Floor</h4>
          <h4>Portland, Maine</h4>
        </div>
      </div>
    </section>
    <footer>
      <h2>The Tea Cozy</h2>
      <h5>contact@theteacozy.com</h5>
      <h5>917-555-8904</h5>
    </footer>
  </body>
</html>

CSS:


body{
    font-family: Helvetica, sans-serif;
    font-size: 22px;
    color: seashell;
    background-color: black;
    text-align: center;
    opacity: 0.9;
    margin: 0;
}
a{
    color: seashell;
}

header{
    /* padding: 10px; */
    height: 69px;
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: seashell 1px solid;
    position: fixed;
    background-color: black;

}
header img{
    height: 50px;
    max-width: 1200px;
    padding: 10px;
}
ul{
    padding: 10px;
    display: flex;
    gap: 20px;
}
li{
    list-style: none;
}

/* ======================================== */

.mission{
    background-image: url(./images/img-mission-background.jpg);
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center;
    max-width: 1200px;
    height: 700px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    margin: 0 auto;
}

.mission_card{
    width: 100%;
    background-color: black;
}

/* ======================================== */

.totm {
    width: 100%;
    margin: 10px;
    justify-self: center;
}
.totm h2 + h4{
    margin: 0 auto;
    padding: 10px;
    max-width: 1000px;
}

.totm_imgs {
    max-width: 1000px;
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
    margin: 0 auto;
}

.totm_img img{
    width: 300px;
    height: 200px;
}

/* ======================================== */

.locations{
    min-height: 500px;
    max-width: 1200px;
    background-image: url(images/img-locations-background.jpg);
    background-size: cover;
    background-repeat: no-repeat;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 auto;
}
.location_container{
    min-height: 500px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    background-color: transparent;
}
.location_container h2{
    width: 100%;
    margin-bottom: 0px;
    height: fit-content;
    background-color: transparent;
}
.location_card{
    opacity: 1;
    background-color: black;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    width: 300px;
    margin: 15px 20px;

}
.location_card > *{
    width: 100%;
}