如何将弹性项目行变成两列？

Question

朋友们，我的网页上有一个名为“服务”的部分。本节包含4个列表。每个列表都包装在div中。每个div是一个flex-item，并且flex基础为25％。这4个div排成一排。但是，当屏幕尺寸缩小到775px时，我想将最后一个显示在列表中，并将它们放在前两个之下，从而创建两列。我对flexbox不太熟悉，该怎么办？

.content {
	display: flex;
}

.content > .skills {
	flex-basis: 25%;
	margin-top: 15px;
	margin-bottom: 15px;
}

<div class="content">
  <ul class="skills">
    <li>Flatwork</li>
    <li>Paving</li>
    <li>Driveways</li>
    <li>Sidewalks</li>
  </ul>
  <ul class="skills">
    <li>Foundations</li>
    <li>Flooring</li>
    <li>Seismic Retrofit</li>
    <li>Other Concrete Concerns</li>
  </ul>
  <ul class="skills">
    <li>Commercial</li>
    <li>Residential</li>
    <li>Decks and Patios</li>
    <li>Kitchen Flooring</li>
  </ul>
  <ul class="skills">
    <li>Demolition</li>
    <li>Grading/Clean up</li>
    <li>Slab Repair</li>
    <li>Curb Repair</li>				
  </ul>
</div>

Answer 1

一种解决方案是在显示小于您的{{1}断点时，使用响应式样式将flex-wrap: wrap;应用于.content，将flex-basis: 50%;应用于.content > div }}。

这可以通过将以下内容添加到CSS中来完成：

775px

有关有效的演示，请参见以下代码段：

/* Only applies the styling when screen is between 0px and 775px wide */
@media (max-width: 775px) {

  .services .content {
    /* Tells flex box to allow child elements to "wrap" onto next row if needed */
    flex-wrap: wrap;
  }

  .services .content div {
    /* Tells children of .content to occupy half of parents width, resulting in two columns */
    flex-basis: 50%;
  }
}

  html,
body {
  margin: 0;
  padding: 0;
}

nav li a {
  text-decoration-line: none;
  color: rgba(102, 102, 102, 0.75);
}

.wrapper2 {
  width: 100%;
  height: 65vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: rgba(0, 0, 0, 0.3);
}

header {
  background-image: url(../img/pexels.jpg);
  background-position: center;
  background-size: cover;
  height: 65vh;
  background-attachment: fixed;
  background-repeat: no-repeat;
}

header h1 {
  color: white;
  margin: 0;
  font-size: 5rem;
  font-family: 'Montserrat';
  font-weight: bolder;
}

nav {
  background-color: white;
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 2;
  box-shadow: 0px 0px 100px grey;
}

nav ul {
  margin-right: 0px;
  margin-top: 25px;
}

nav li {
  display: inline-block;
  font-size: 1.55rem;
  margin-right: 20px;
  font-family: 'Rajdhani';
  color: rgba(102, 102, 102, 0.75);
}

nav li a:hover {
  cursor: pointer;
  color: #1a1a1a;
  transition: all 0.7s ease;
}

.after:after {
  position: relative;
  left: 12px;
  top: 2px;
  display: inline-block;
  content: "";
  width: 1px;
  height: 20px;
  background-color: rgba(102, 102, 102, 0.25);
}

.logo {
  color: red;
  font-size: 3.7rem;
  margin: 10px;
  opacity: 1;
  margin-left: 30px;
}


/*---ABOUT---*/

.history h2 {
  font-family: 'Rajdhani';
  color: rgba(102, 102, 102, 0.85);
  font-size: 3rem;
  text-align: center;
  margin-top: 20px;
  margin-bottom: 20px;
}

.history h2:after {
  content: '';
  width: 18px;
  height: 2px;
  background-color: red;
  display: inline-block;
  margin-left: 5px;
  margin-bottom: 13px;
}

.history h2:before {
  content: '';
  width: 18px;
  height: 2px;
  background-color: red;
  display: inline-block;
  margin-right: 5px;
  margin-bottom: 13px;
}

.history p {
  color: rgba(102, 102, 102, 0.85);
  font-family: 'Rajdhani';
  font-size: 1.7rem;
  text-align: center;
  width: 90%;
  margin-right: auto;
  margin-left: auto;
  margin-top: 35px;
  position: relative;
  top: -20px;
}


/*---SERVICES---*/

.services {
  background-image: url(../img/pour.jpeg);
  background-size: cover;
  background-attachment: fixed;
}

.services .wrapper {
  width: 100%;
  height: 250px;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: rgba(0, 0, 0, 0.3);
}

.services {
  color: white;
  font-family: 'Montserrat';
  font-weight: bolder;
  font-size: 3rem;
}

.services .content {
  display: flex;
  background-color: white;
}

.services .content div {
  flex-basis: 25%;
  margin-top: 15px;
  margin-bottom: 15px;
}

.services ul {
  color: red;
  font-size: 1.8rem;
  font-family: 'Rajdhani';
  list-style-type: square;
  margin-left: 50px;
  margin-top: 0;
  margin-bottom: 0;
}

.skills p {
  margin: 10px;
}

.content .move {
  align-self: flex-end;
}


/*---TESTIMONY---*/

.testimony {
  background-image: url('../img/wall4.jpg');
  display: flex;
  justify-content: space-around;
  background-attachment: fixed;
  background-size: cover;
}

.testimony h1 {
  margin-bottom: 20px;
  margin-top: 20px;
  color: white;
  font-family: 'Arvo';
  padding: 30px;
  display: inline-block;
  flex-basis: 40%;
  margin-left: 30px;
}

.testimony span {
  color: white;
  font-size: 2.3rem;
}

.testimony .quote {
  font-family: 'Rajdhani';
  font-size: 1.2rem;
  margin-left: 40px;
}

.testimony .left-quote {
  position: relative;
  left: 60px;
  top: 30px
}

.fa-quote-right {
  position: relative;
  right: 35px;
  top: 30px;
}

.testimony .move {
  right: 68px;
}


/*---FOOTER---*/

.footer .wrapper {
  display: flex;
}

.footer div {
  display: inline-block;
  flex-basis: 29%;
  font-family: 'Rajdhani';
  color: rgba(102, 102, 102, 1);
  margin-top: 5px;
  justify-content: space-around;
}

.footer h1 {
  font-size: 2rem;
  margin-top: 15px;
}

.social .inner {
  width: 100%;
}

.footer .inner:before {
  display: inline-block;
  content: '';
  width: 29%;
  height: 2px;
  background-color: rgba(102, 102, 102, 0.6);
  position: absolute;
  margin-top: 54px;
}

.footer h1 span {
  display: inline;
  position: relative;
}

.footer h1 span:after {
  content: '';
  height: 2px;
  width: 100%;
  background-color: red;
  position: absolute;
  bottom: 0;
  left: 0;
}

.wrap:before {
  content: '';
  width: 100px;
  height: 2px;
  background-color: red;
  position: absolute;
  margin-top: 55px;
}

.links a {
  display: block;
  text-decoration-line: none;
  color: rgba(102, 102, 102, 1);
  font-size: 1.1rem;
  position: relative;
  top: -17px;
  transition: color 0.4s ease;
}

.links a:hover {
  color: red;
}

.contact p {
  position: relative;
  top: -10px;
}

.social i {
  font-size: 1.7rem;
  margin-right: 5px;
  position: relative;
  top: -20px;
  color: rgba(102, 102, 102, 0.7);
  transition: all 0.4s ease;
}

.social i:hover {
  color: red;
  cursor: pointer;
}

#msg {
  margin-top: -15px;
}

.footer-textarea {
  background-color: rgba(102, 102, 102, 0.2);
  padding: 0;
  outline: none;
  font-size: 1.2rem;
  color: rgba(102, 102, 102, 1);
  resize: none;
  width: 99.5%;
}

.footer button {
  float: right;
  margin-top: -17px;
  border: none;
  font-family: 'Rajdhani';
  font-size: 1.2rem;
  transition: all ease 0.4s;
  outline: none;
}

button:hover {
  cursor: pointer;
  color: red;
}

.dark {
  color: red;
}

.copyright {
  position: absolute;
  background-color: white;
  text-align: center;
  width: 100%;
  margin-bottom: 0;
  font-size: 1.2rem;
  padding-bottom: 4px;
}


/*-------MEDIA QUERIES-------*/

@media screen and (min-width: 2460px) {
  /*---NAV---*/
  nav li {
    font-size: 3rem;
  }
  .logo {
    font-size: 8rem;
  }
  .after:after {
    width: 3px;
    height: 40px;
    margin-left: 5px;
    margin-right: 5px;
  }
  /*---MAIN---*/
  header h1 {
    font-size: 9rem;
  }
  .history h2 {
    font-size: 6rem;
    margin-bottom: 30px;
  }
  .history h2:before,
  .history h2:after {
    height: 4px;
    width: 35px;
    margin-bottom: 25px;
  }
  .history p {
    font-size: 3.4rem;
  }
  .services h1 {
    font-size: 8rem;
  }
  .services .wrapper {
    height: 400px;
  }
  .services h2 {
    font-size: 6rem;
  }
  .services h2:before,
  .services h2:after {
    height: 4px;
    width: 35px;
    margin-bottom: 25px;
  }
  .services li {
    font-size: 3.5rem;
  }
  .services ul {
    margin-left: 150px;
  }
  .testimony i {
    font-size: 5rem;
    padding-top: 30px;
  }
  .testimony h1 {
    font-size: 2.7rem;
    padding-bottom: 60px;
  }
  .testimony .quote {
    font-size: 2.3rem;
  }
  /*---FOOTER---*/
  .footer h1 {
    font-size: 4.5rem;
    padding-top: 15px;
  }
  .footer h1 span:after {
    height: 4px;
  }
  .footer .inner:before {
    height: 4px;
    margin-top: 118.25px;
  }
  .links a {
    font-size: 2.5rem;
    top: -20px;
  }
  .social i {
    font-size: 3.5rem;
    margin-right: 10px;
    top: -40px;
  }
  .footer button {
    font-size: 2.5rem;
    margin-right: 14.25%;
    padding-left: 10px;
    padding-right: 10px;
    margin-top: -37px;
  }
  .footer textarea {
    font-size: 2.5rem;
    width: 85%;
  }
  .contact p {
    font-size: 2.5rem;
    margin-bottom: 35px;
    margin-top: 35px;
  }
  .copyright {
    font-size: 2.5rem;
  }
}

@media screen and (min-width: 1901px) {
  .footer button {
    margin-left: 14%;
  }
}


/*---LAPTOP-LARGE---*/

@media screen and (max-width: 1593px) {
  .skills li {
    font-size: 1.65rem;
  }
  .skills p {
    font-size: 1.65rem;
  }
}

@media screen and (max-width: 1497px) {
  .skills li {
    font-size: 1.5rem;
  }
  .skills p {
    font-size: 1.5rem;
  }
}

@media screen and (max-width: 1448px) {
  .skills li {
    font-size: 1.35rem;
  }
  .skills p {
    font-size: 1.35rem;
  }
}

@media screen and (max-width: 1440px) {
  /*---FOOTER---*/
  .footer button {
    margin-left: 16.5%;
  }
}

@media screen and (max-width: 1332px) {
  .history p {
    font-size: 1.5rem;
  }
}

@media screen and (max-width: 1091px) {
  .skills p {
    font-size: 1.15rem;
  }
}


/*---TABLET-LARGE---*/

@media screen and (max-width: 985px) {
  .history h2 {
    font-size: 2.5rem;
    margin-top: 15px;
    margin-bottom: 15px;
  }
  .history h2:before,
  .history h2:after {
    width: 15px;
    margin-bottom: 11px;
  }
  .history p {
    margin-top: 25px;
    font-size: 1.4rem;
  }
  .services ul {
    margin-left: 20px;
  }
}

@media screen and (max-width: 924px) {
  .logo {
    font-size: 3rem;
  }
  nav li {
    font-size: 1.4rem;
  }
}

@media screen and (max-width: 829px) {
  .footer .contact p {
    font-size: 1rem;
    margin: 3px;
  }
  .footer textarea {
    font-size: 1rem;
  }
}

@media screen and (max-width: 836px) {
  .services ul {
    margin-left: 5px;
  }
}

@media screen and (max-width: 812px) {
  /*---MAIN---*/
  .history p {
    font-size: 1.3rem;
  }
  .padding {
    padding-top: 0px;
  }
  .testimony h1 {
    font-size: 1.25rem;
  }
  /*---FOOTER---*/
  .footer button {
    margin-left: 8.5%;
  }
  .contact .inner {
    margin-right: 20px;
  }
}


/*---TABLET---*/

@media screen and (max-width: 768px) {
  /*---MAIN--*/
  header,
  .wrapper2 {
    height: 65vh;
  }
  .services ul {
    font-size: 1.5rem;
    margin-left: 30px;
  }
  .padding2 {
    padding-top: 10px;
  }
  .testimony h1 {
    font-size: 1.1rem;
  }
  .testimony .fa-quote-right {
    display: none;
  }
}


/*------LANDSCAPE-MODE-MOBILE------*/

@media screen and (max-width: 715px) {
  /*---NAV---*/
  nav ul {
    padding-left: 0;
    margin: 0;
  }
  nav li {
    font-size: 1.4rem;
  }
  nav .logo {
    font-size: 2.5rem;
  }
  /*---MAIN---*/
  .history p {
    font-size: 1.5rem;
  }
  .testimony {
    flex-direction: column;
  }
  .testimony h1 {
    margin-left: 30px;
    font-size: 1.45rem;
  }
  .move-quote {
    position: relative;
    top: -30px;
  }
  .fa-quote-right {
    position: absolute;
    display: none;
  }
  .padding {
    top: -35px;
  }
}

@media screen and (max-width: 640px) {
  header h1 {
    font-size: 4rem;
  }
  .services h1 {
    font-size: 3.5rem;
  }
  /*---FOOTER---*/
  .footer h1 {
    font-size: 1.5rem;
  }
  .footer .inner:before {
    margin-top: 43px;
  }
  .links a {
    font-size: 1rem;
    top: -14px;
  }
  .social i {
    font-size: 1.5rem;
    margin-right: 2px;
    top: -17px;
  }
  .footer button {
    margin-top: -14px;
    font-size: 1rem;
  }
  .footer textarea {
    font
  }
  @media screen and (max-width: 626px) {
    nav li {
      font-size: 1.27rem;
    }
    /*---FOOTER---*/
    .footer .wrapper {
      display: flex;
      flex-direction: column;
    }
    .footer div {
      margin: 0;
    }
    .footer h1 {
      font-size: 2rem;
      margin-top: 10px;
    }
    .footer .inner {
      margin: 0;
    }
    .footer .inner:before {
      display: inline-block;
      content: '';
      width: 100vw;
      height: 2px;
      background-color: rgba(102, 102, 102, 0.6);
      position: absolute;
      margin-top: 48px;
    }
    .footer h1 span:after {
      content: '';
      height: 2px;
      width: 100%;
      background-color: red;
      position: absolute;
      bottom: 1px;
      left: 0;
    }
    .social .inner {
      position: relative;
      top: -10px;
    }
    .links a {
      margin-left: 5px;
    }
    .social h1 {
      margin-bottom: 10px;
    }
    #msg {
      font-size: 1rem;
      margin-bottom: 0;
      margin-right: 25.5%;
      position: absolute;
      right: 5px;
      top: 80px;
    }
    .footer button {
      right: 9.25%;
      margin-top: 0.2px;
    }
    .social i {
      font-size: 1.8rem;
      margin-right: 2px;
      position: relative;
      top: -5px;
      left: 5px;
      color: rgba(102, 102, 102, 0.7);
      transition: all 0.4s ease;
    }
    .footer-textarea {
      width: 88.5%;
      margin-top: 25px;
      margin-left: 5px;
    }
    .contact p {
      margin: 5px;
      font-size: 1.2rem;
    }
    .copyright {
      background-color: red;
      padding-top: 10px;
      padding-bottom: 10px;
    }
    .copyright span {
      color: white;
      background-color: red;
    }
  }
  @media screen and (max-width: 586px) {
    /*---MAIN---*/
    header h1 {
      font-size: 3.5rem;
    }
    .services li {
      font-size: 1.3rem;
    }
    .services ul {
      padding: 0;
      margin-left: 50px;
    }
  }
  @media screen and (max-width: 568px) {
    /*---MAIN---*/
    header h1,
    .services h1 {
      font-size: 4rem;
    }
    .services li {
      font-size: 1.1rem;
    }
    .services ul {
      margin-left: 10px;
    }
    .padding {
      padding-top: 10px;
    }
    /*---FOOTER---*/
    .footer .wrapper {
      display: flex;
      flex-direction: column;
    }
    .footer div {
      margin: 0;
    }
    .footer h1 {
      font-size: 2rem;
      margin-top: 10px;
    }
    .footer .inner {
      margin: 0;
    }
    .footer .inner:before {
      display: inline-block;
      content: '';
      width: 100%;
      height: 2px;
      background-color: rgba(102, 102, 102, 0.6);
      position: absolute;
      margin-top: 48px;
    }
    .footer h1 span:after {
      content: '';
      height: 2px;
      width: 100%;
      background-color: red;
      position: absolute;
      bottom: 1px;
      left: 0;
    }
    .social .inner {
      position: relative;
      top: -10px;
    }
    .social .inner:before {
      width: 100vw;
    }
    .links a {
      margin-left: 5px;
    }
    .social h1 {
      margin-bottom: 10px;
    }
    #msg {
      font-size: 1rem;
      margin-bottom: 0;
      margin-right: 25.5%;
      position: absolute;
      right: 5px;
      top: 80px;
    }
    .footer button {
      right: 9.25%;
      margin-top: 0.2px;
    }
    .social i {
      font-size: 1.8rem;
      margin-right: 2px;
      position: relative;
      top: -5px;
      left: 5px;
      color: rgba(102, 102, 102, 0.7);
      transition: all 0.4s ease;
    }
    .footer-textarea {
      width: 88.5%;
      margin-top: 30px;
      margin-left: 5px;
    }
    .contact p {
      margin: 5px;
      font-size: 1.2rem;
    }
    .copyright {
      background-color: red;
    }
    .copyright span {
      color: white;
      background-color: red;
    }
  }
  @media screen and (max-width: 530px) {
    nav li {
      font-size: 1.27rem;
      margin-right: 7px;
    }
    .after:after {
      left: 5.5px;
      top: 4px;
    }
    .logo {
      margin-left: 15px;
    }
  }
  @media screen and (max-width: 517px) {
    /*---NAV---*/
    nav li {
      font-size: 1.1rem;
    }
    /*---MAIN---*/
    header h1 {
      font-size: 3rem;
    }
    /*---FOOTER---*/
    .footer .wrapper {
      display: flex;
      flex-direction: column;
    }
    .footer div {
      margin: 0;
    }
    .footer h1 {
      font-size: 2rem;
      margin-top: 10px;
    }
    .footer .inner {
      margin: 0;
    }
    .footer .inner:before {
      display: inline-block;
      content: '';
      width: 100vw;
      height: 2px;
      background-color: rgba(102, 102, 102, 0.6);
      position: absolute;
      margin-top: 48px;
    }
    .social .inner {
      position: relative;
      top: -10px;
    }
    .footer h1 span:after {
      content: '';
      height: 2px;
      width: 100%;
      background-color: red;
      position: absolute;
      bottom: 1px;
      left: 0;
    }
    .links a {
      margin-left: 5px;
    }
    .social h1 {
      margin-bottom: 10px;
    }
    #msg {
      font-size: 1.3rem;
      margin-bottom: 0;
      float: right;
      margin-right: 25.5%;
      position: relative;
      top: 15px;
    }
    .footer button {
      right: 9.25%;
      margin-top: 0.2px;
    }
    .social i {
      font-size: 1.8rem;
      margin-right: 7px;
      position: relative;
      top: -5px;
      left: 5px;
      color: rgba(102, 102, 102, 0.7);
      transition: all 0.4s ease;
    }
    .footer-textarea {
      width: 88.5%;
      margin-left: 5px;
      margin-top: 0px;
      position: relative;
      top: 10px;
    }
    .contact p {
      margin: 5px;
      font-size: 1.2rem;
    }
    .copyright {
      background-color: red;
    }
    .copyright span {
      color: white;
      background-color: red;
    }
  }
  @media only screen and (max-width: 775px) {
    .content {
      flex-wrap: wrap;
    }
    .services .content div {
      flex-basis: 50%;
    }
  }