Muundo wa Tovuti yenye Safu Tatu katika CSS

Hebu sasa tufanye muundo wa safu tatu. Hapa kuna mfano wa kile tunachopaswa kupata:

Kwanza tuandike muundo wa tovuti:

html<div id="wrapper">
  <div id="header">
    kichwa
  </div>
  <div id="container">
    <div id="left">
      upau wa kushoto
    </div>
    <div id="content">
      maudhui
    </div>
    <div id="right">
      upau wa kulia
    </div>
  </div>
  <div id="footer">
    kiwambo
  </div>
</div>

Tuweke upana wa kifurushi na tukikatie katikati:

css#wrapper {
  width: 1100px;
  margin: 30px auto;
  border: 1px solid black;
}

Tuweke vitalu vya chombo kwa mstari mmoja:

css#container {
  display: flex;
}

Sasa tupeana upana wa vitalu ili kwa jumla wape upana wa kifurushi:

css#content {
  width: 700px;
}
#left {
  width: 200px;
}
#right {
  width: 200px;
}

Hebu sasa tuongeze margin, tukiondoa upana wao kutoka kwa maudhui:

css#content {
  width: 660px;
}
#left {
  width: 200px;
  margin-right: 20px;
}
#right {
  width: 200px;
  margin-left: 20px;
}

Tuongeze mitindo mingine:

css#content {
  width: 660px;
  height: 700px;
  padding: 20px;
  border: 1px solid black;
}
#left {
  width: 200px;
  margin-right: 20px;
  padding: 20px;
  border: 1px solid black;
}
#right {
  width: 200px;
  margin-left: 20px;
  padding: 20px;
  border: 1px solid black;
}

Tuandike msimbo wa mwisho:

html<div id="wrapper">
  <div id="header">
    kichwa
  </div>
  <div id="container">
    <div id="left">
      upau wa kushoto
    </div>
    <div id="content">
      maudhui
    </div>
    <div id="right">
      upau wa kulia
    </div>
  </div>
  <div id="footer">
    kiwambo
  </div>
</div>

css* {
  box-sizing: border-box;
}

#wrapper {
  width: 1100px;
  margin: 30px auto;
  border: 1px solid black;
}
#header {
  height: 200px;
  padding: 20px;
  border: 1px solid black;
}
#container {
  display: flex;
}
#content {
  width: 660px;
  height: 700px;
  padding: 20px;
  border: 1px solid black;
}
#left {
  width: 200px;
  margin-right: 20px;
  padding: 20px;
  border: 1px solid black;
}
#right {
  width: 200px;
  margin-left: 20px;
  padding: 20px;
  border: 1px solid black;
}
#footer {
  height: 200px;
  padding: 20px;
  border: 1px solid black;
}