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HTML 

              
                    <h1>Table template</h1>
    <table>
       <caption>Data about the planets of our solar system (Planetary facts taken from <a href="http://nssdc.gsfc.nasa.gov/planetary/factsheet/">Nasa's Planetary Fact Sheet - Metric</a>).</caption>
     <colgroup><col span="2"><col style="border:2px solid black"><col span="9"></colgroup>
      <thead>
        <tr>
          <td colspan="2">&nbsp;</td>
          <th id="name">Name</th>
          <th id="mass">Mass (10<sup>24</sup>kg)</th>
          <th id="diam">Diameter (km)</th>
          <th id="dens">Density (kg/m<sup>3</sup>)</th>
          <th id="grav">Gravity (m/s<sup>2</sup>)</th>
          <th id="lday">Length of day (hours)</th>
          <th id="dist">Distance from Sun (10<sup>6</sup>km)</th>
          <th id="temp">Mean temperature (В°C)</th>
          <th id="moons">Number of moons</th>
          <th id="note">Notes</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th id="terr" colspan="2" rowspan="4">Terrestrial planets</th>
          <th id="merc">Mercury</th>
          <td headers="terr merc mass">0.330</td>
          <td headers="terr merc diam">4,879</td>
          <td headers="terr merc dens">5427</td>
          <td headers="terr merc grav">3.7</td>
          <td headers="terr merc lday">4222.6</td>
          <td headers="terr merc dist">57.9</td>
          <td headers="terr merc temp">167</td>
          <td headers="terr merc moons">0</td>
          <td headers="terr merc note">Closest to the Sun</td>
        </tr>
        <tr>
          <th id="venus">Venus</th>
          <td headers="terr venus mass">4.87</td>
          <td headers="terr venus diam">12,104</td>
          <td headers="terr venus dens">5243</td>
          <td headers="terr venus grav">8.9</td>
          <td headers="terr venus lday">2802.0</td>
          <td headers="terr venus dist">108.2</td>
          <td headers="terr venus temp">464</td>
          <td headers="terr venus moons">0</td>
          <td headers="terr venus note">&nbsp;</td>
        </tr>
        <tr>
          <th id="earth">Earth</th>
          <td headers="terr earth mass">5.97</td>
          <td headers="terr earth diam">12,756</td>
          <td headers="terr earth dens">5514</td>
          <td headers="terr earth grav">9.8</td>
          <td headers="terr earth lday">24.0</td>
          <td headers="terr earth dist">149.6</td>
          <td headers="terr earth temp">15</td>
          <td headers="terr earth moons">1</td>
          <td headers="terr earth note">Our world</td>
        </tr>
        <tr>
          <th id="mars">Mars</th>
          <td headers="terr mars mass">0.642</td>
          <td headers="terr mars diam">6,792</td>
          <td headers="terr mars dens">3933</td>
          <td headers="terr mars grav">3.7</td>
          <td headers="terr mars lday">24.7</td>
          <td headers="terr mars dist">227.9</td>
          <td headers="terr mars temp">-65</td>
          <td headers="terr mars moons">2</td>
          <td headers="terr mars note">The red planet</td>
        </tr>
        <tr>
          <th id="jovi" rowspan="4">Jovian planets</th>
          <th id="gas" rowspan="2">Gas giants</th>
          <th id="jupi">Jupiter</th>
          <td headers="jovi gas jupi mass">1898</td>
          <td headers="jovi gas jupi diam">142,984</td>
          <td headers="jovi gas jupi dens">1326</td>
          <td headers="jovi gas jupi grav">23.1</td>
          <td headers="jovi gas jupi lday">9.9</td>
          <td headers="jovi gas jupi dist">778.6</td>
          <td headers="jovi gas jupi temp">-110</td>
          <td headers="jovi gas jupi moons">67</td>
          <td headers="jovi gas jupi note">The largest planet</td>
        </tr>
        <tr>
          <th id="saturn">Saturn</th>
          <td headers="jovi gas saturn mass">568</td>
          <td headers="jovi gas saturn diam">120,536</td>
          <td headers="jovi gas saturn dens">687</td>
          <td headers="jovi gas saturn grav">9.0</td>
          <td headers="jovi gas saturn lday">10.7</td>
          <td headers="jovi gas saturn dist">1433.5</td>
          <td headers="jovi gas saturn temp">-140</td>
          <td headers="jovi gas saturn moons">62</td>
          <td headers="jovi gas saturn note">&nbsp;</td>
        </tr>
        <tr>
          <th id="ice" rowspan="2">Ice giants</th>
          <th id="uran">Uranus</th>
          <td headers="jovi ice uran mass">86.8</td>
          <td headers="jovi ice uran diam">51,118</td>
          <td headers="jovi ice uran dens">1271</td>
          <td headers="jovi ice uran grav">8.7</td>
          <td headers="jovi ice uran lday">17.2</td>
          <td headers="jovi ice uran dist">2872.5</td>
          <td headers="jovi ice uran temp">-195</td>
          <td headers="jovi ice uran moons">27</td>
          <td headers="jovi ice uran note">&nbsp;</td>
        </tr>
        <tr>
          <th id="nept">Neptune</th>
          <td headers="jovi ice nept mass">102</td>
          <td headers="jovi ice nept diam">49,528</td>
          <td headers="jovi ice nept dens">1638</td>
          <td headers="jovi ice nept grav">11.0</td>
          <td headers="jovi ice nept lday">16.1</td>
          <td headers="jovi ice nept dist">4495.1</td>
          <td headers="jovi ice nept temp">-200</td>
          <td headers="jovi ice nept moons">14</td>
          <td headers="jovi ice nept note">&nbsp;</td>
        </tr>
        <tr>
          <th id="dwarf" colspan="2">Dwarf planets*</th>
          <th id="pluto">Pluto</th>
          <td headers="dwarf pluto mass">0.0146</td>
          <td headers="dwarf pluto diam">2,370</td>
          <td headers="dwarf pluto dens">2095</td>
          <td headers="dwarf pluto grav">0.7</td>
          <td headers="dwarf pluto lday">153.3</td>
          <td headers="dwarf pluto dist">5906.4</td>
          <td headers="dwarf pluto temp">-225</td>
          <td headers="dwarf pluto moons">5</td>
          <td headers="dwarf pluto note">Declassified as a planet in 2006, but this <a href="http://www.usatoday.com/story/tech/2014/10/02/pluto-planet-solar-system/16578959/">remains controversial</a>.</td>
        </tr>
      </tbody>
    </table>
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CSS 

              
                html {
  font-family: sans-serif;
}

table {
  border-collapse: collapse;
  border: 2px solid rgb(200,200,200);
  letter-spacing: 1px;
  font-size: 0.8rem;
}

td, th {
  border: 1px solid rgb(190,190,190);
  padding: 10px 20px;
}

th {
  background-color: rgb(235,235,235);
}

td {
  text-align: center;
}

tr:nth-child(even) td {
  background-color: rgb(250,250,250);
}

tr:nth-child(odd) td {
  background-color: rgb(245,245,245);
}

caption {
  padding: 10px;
}
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JS
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