解决HTML布局重叠问题：理解与实践

* {
  box-sizing: border-box;
}

:root {
  --mobile-width: 375px;
  --light-blue: hsl(224, 93%, 58%);
}

.mmargin {
  margin: 50px auto; /* 确保有足够的上下外边距，并水平居中 */
}

body {
  margin: 0;
  padding: 0 ;
  font-family: "Open Sans", sans-serif;
  font-weight: 400;
}

h1,
h2,
h3 {
  font-family: "Raleway", sans-serif;
  font-weight: 700;
}

button:hover {
  opacity: 0.5;
  cursor: pointer;
}

/* .sec-2 部分的样式 */
.sec-2 { /* 使用类选择器 */
  width: var(--mobile-width);
  display: flex;
  flex-direction: column;
}

.sec-2 .image {
  margin-bottom: 50px;
}

.sec-2 .image img {
  max-width: 100%;
}

.sec-2 .text h2 {
  font-size: 20px;
  text-align: center;
  margin: 30px 0;
}

.sec-2 .text p.p {
  margin: 50px auto;
  text-align: center;
  color: #3da08f;
  position: relative;
}

.sec-2 .text p.p:hover {
  opacity: 0.5;
  cursor: pointer;
}

.sec-2 .text p.p::before {
  content: "";
  width: 175px;
  height: 2px;
  background-color: #3da08f;
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  bottom: -5px; /* 修正为单位 */
}

.sec-2 .text p.p img {
  width: 25px;
  vertical-align: middle;
}

.sec-2 .text .card {
  display: flex;
  flex-direction: column;
  box-shadow: 0 0 10px rgb(197, 197, 197);
  padding: 20px;
}

.sec-2 .text .card .image1 {
  width: 40px;
}

.sec-2 .text .card .image1 img {
  width: 50%;
}

.sec-2 .text .av {
  display: flex;
  align-items: center;
  gap: 15px;
  margin: 30px 0;
}

.sec-2 .text .av .image2 {
  width: 50px;
}

.sec-2 .text .av img {
  max-width: 100%;
  border-radius: 50%;
}

.sec-2 .text .txt {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.sec-2 .text .txt h3 {
  margin: 0;
}

.sec-2 .text .txt p {
  margin: 0;
}

/* .sec3 部分的样式 */
.sec3 {
  background-color: hsl(238, 22%, 44%);
  display: block; /* 明确设置为块级元素，确保独立占据空间 */
  flex-direction: column; /* 虽然设置了flex-direction，但display:block优先，如果需要flex布局，应为display:flex */
  justify-content: center;
  color: white;
  padding: 50px;
}

.sec3 .text h2 {
  text-align: center;
}

.sec3 .text p {
  text-align: center;
  font-size: 18px;
  line-height: 1.5;
}

.sec3 form {
  margin: 30px auto;
}

.sec3 form input {
  width: 50%;
  margin-bottom: 10px;
  opacity: 0.3;
}

.sec3 form button {
  width: 50%;
  text-align: center;
}

<div class="mmargin sec-2"> <!-- 使用 div 标签并添加 class="sec-2" -->
   <div class="image">
   </div>
   <div class="text">
   <h2>Stay productive, wherever you are</h2>
   <p>
      Lorem ipsum dolor sit amet consectetur adipisicing elit. Temporibus
      doloribus ipsa cum. Sapiente quisquam error magnam odit repellendus
      nihil dolorem quis
   </p>
   <p>
      Lorem ipsum dolor sit amet consectetur adipisicing elit. Temporibus
      doloribus ipsa cum. Sapiente quisquam error magnam odit repellendus
      nihil dolorem quis
   </p>
   <p class="p">
      See how Fylo works 
   </p>
   <div class="card">
   <div class="image1">
   </div>
   <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Qui omnis ducimus veniam, cupidita
   </p>
   <div class="av">
      <div class="image2">
      </div>
      <div class="txt">
         <h3>
            Kyle Burton
         </h3>
         <p>
            Founder & CEO, Huddle
         </p>
      </div>
   </div>
</div>
<!-- section 2  -->
<!-- section-3  -->
<div class="sec3 mmargin">
   <div class="text">
      <h2>
         Get early access today
      </h2>
      <p>
         Lorem ipsum dolor sit amet consectetur adipisicing elit. Aliquid sapiente a alias libero labore rerum assumenda cupiditate illum iure adipisci. Veniam vel voluptatem deleniti officia culpa sed, asperiores eveniet fugiat.
      </p>
   </div>
   <form action="">
      <input type="email" placeholder="email@example.com">
      <button>
      Get Started For Free
      </button>
   </form>
</div>