<!DOCTYPE html>
<!--Codingthai.com--> 
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="style.css" />
    <title>Drink Water</title>
  </head>
  <body>
    <h1>Drink Water</h1>
    <h3>Goal: 2 Liters</h3>

    <div class="cup">
      <div class="remained" id="remained">
        <span id="liters"></span>
        <small>Remained</small>
      </div>

      <div class="percentage" id="percentage"></div>
    </div>

    <p class="text">Select how many glasses of water that you have drank</p>

    <div class="cups">
      <div class="cup cup-small">250 ml</div>
      <div class="cup cup-small">250 ml</div>
      <div class="cup cup-small">250 ml</div>
      <div class="cup cup-small">250 ml</div>
      <div class="cup cup-small">250 ml</div>
      <div class="cup cup-small">250 ml</div>
      <div class="cup cup-small">250 ml</div>
      <div class="cup cup-small">250 ml</div>
    </div>

    <script src="script.js"></script>
  </body>
</html>
@import url('https://fonts.googleapis.com/css?family=Montserrat:400,600&display=swap');

:root {
  --border-color: #144fc6;
  --fill-color: #6ab3f8;
}

* {
  box-sizing: border-box;
}

body {
  background-color: #3494e4;
  color: #fff;
  font-family: 'Montserrat', sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: 40px;
}

h1 {
  margin: 10px 0 0;
}

h3 {
  font-weight: 400;
  margin: 10px 0;
}

.cup {
  background-color: #fff;
  border: 4px solid var(--border-color);
  color: var(--border-color);
  border-radius: 0 0 40px 40px;
  height: 330px;
  width: 150px;
  margin: 30px 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.cup.cup-small {
  height: 95px;
  width: 50px;
  border-radius: 0 0 15px 15px;
  background-color: rgba(255, 255, 255, 0.9);
  cursor: pointer;
  font-size: 14px;
  align-items: center;
  justify-content: center;
  text-align: center;
  margin: 5px;
  transition: 0.3s ease;
}

.cup.cup-small.full {
  background-color: var(--fill-color);
  color: #fff;
}

.cups {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  width: 280px;
}

.remained {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  flex: 1;
  transition: 0.3s ease;
}

.remained span {
  font-size: 20px;
  font-weight: bold;
}

.remained small {
  font-size: 12px;
}

.percentage {
  background-color: var(--fill-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 30px;
  height: 0;
  transition: 0.3s ease;
}

.text {
  text-align: center;
  margin: 0 0 5px;
}
const smallCups = document.querySelectorAll('.cup-small')
const liters = document.getElementById('liters')
const percentage = document.getElementById('percentage')
const remained = document.getElementById('remained')

updateBigCup()

smallCups.forEach((cup, idx) => {
    cup.addEventListener('click', () => highlightCups(idx))
})

function highlightCups(idx) {
    if (idx===7 && smallCups[idx].classList.contains("full")) idx--;
    else if(smallCups[idx].classList.contains('full') && !smallCups[idx].nextElementSibling.classList.contains('full')) {
        idx--
    }

    smallCups.forEach((cup, idx2) => {
        if(idx2 <= idx) {
            cup.classList.add('full')
        } else {
            cup.classList.remove('full')
        }
    })

    updateBigCup()
}

function updateBigCup() {
    const fullCups = document.querySelectorAll('.cup-small.full').length
    const totalCups = smallCups.length

    if(fullCups === 0) {
        percentage.style.visibility = 'hidden'
        percentage.style.height = 0
    } else {
        percentage.style.visibility = 'visible'
        percentage.style.height = `${fullCups / totalCups * 330}px`
        percentage.innerText = `${fullCups / totalCups * 100}%`
    }

    if(fullCups === totalCups) {
        remained.style.visibility = 'hidden'
        remained.style.height = 0
    } else {
        remained.style.visibility = 'visible'
        liters.innerText = `${2 - (250 * fullCups / 1000)}L`
    }
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.