<form>
<div id="digit1">
<input type="checkbox" id="d1-1" class="number1">
<input type="checkbox" id="d1-2" class="number2">
<input type="checkbox" id="d1-3" class="number3">
<input type="checkbox" id="d1-4" class="number4">
<input type="checkbox" id="d1-5" class="number5">
<input type="checkbox" id="d1-6" class="number6">
<input type="checkbox" id="d1-7" class="number7">
<input type="checkbox" id="d1-8" class="number8">
<input type="checkbox" id="d1-9" class="number9">
<div id="digit2">
<input type="checkbox" id="d2-0" class="number0">
<input type="checkbox" id="d2-1" class="number1">
<input type="checkbox" id="d2-2" class="number2">
<input type="checkbox" id="d2-3" class="number3">
<input type="checkbox" id="d2-4" class="number4">
<input type="checkbox" id="d2-5" class="number5">
<input type="checkbox" id="d2-6" class="number6">
<input type="checkbox" id="d2-7" class="number7">
<input type="checkbox" id="d2-8" class="number8">
<input type="checkbox" id="d2-9" class="number9">
<div id="digit3">
<input type="checkbox" id="d3-0" class="number0">
<input type="checkbox" id="d3-1" class="number1">
<input type="checkbox" id="d3-2" class="number2">
<input type="checkbox" id="d3-3" class="number3">
<input type="checkbox" id="d3-4" class="number4">
<input type="checkbox" id="d3-5" class="number5">
<input type="checkbox" id="d3-6" class="number6">
<input type="checkbox" id="d3-7" class="number7">
<input type="checkbox" id="d3-8" class="number8">
<input type="checkbox" id="d3-9" class="number9">
<div id="digit4">
<input type="checkbox" id="d4-0" class="number0">
<input type="checkbox" id="d4-1" class="number1">
<input type="checkbox" id="d4-2" class="number2">
<input type="checkbox" id="d4-3" class="number3">
<input type="checkbox" id="d4-4" class="number4">
<input type="checkbox" id="d4-5" class="number5">
<input type="checkbox" id="d4-6" class="number6">
<input type="checkbox" id="d4-7" class="number7">
<input type="checkbox" id="d4-8" class="number8">
<input type="checkbox" id="d4-9" class="number9">
<div id="digit5">
<input type="checkbox" id="d5-0" class="number0">
<input type="checkbox" id="d5-1" class="number1">
<input type="checkbox" id="d5-2" class="number2">
<input type="checkbox" id="d5-3" class="number3">
<input type="checkbox" id="d5-4" class="number4">
<input type="checkbox" id="d5-5" class="number5">
<input type="checkbox" id="d5-6" class="number6">
<input type="checkbox" id="d5-7" class="number7">
<input type="checkbox" id="d5-8" class="number8">
<input type="checkbox" id="d5-9" class="number9">
<div id="digit6">
<input type="checkbox" id="d6-0" class="number0">
<input type="checkbox" id="d6-1" class="number1">
<input type="checkbox" id="d6-2" class="number2">
<input type="checkbox" id="d6-3" class="number3">
<input type="checkbox" id="d6-4" class="number4">
<input type="checkbox" id="d6-5" class="number5">
<input type="checkbox" id="d6-6" class="number6">
<input type="checkbox" id="d6-7" class="number7">
<input type="checkbox" id="d6-8" class="number8">
<input type="checkbox" id="d6-9" class="number9">
<div id="digit7">
<input type="checkbox" id="d7-0" class="number0">
<input type="checkbox" id="d7-1" class="number1">
<input type="checkbox" id="d7-2" class="number2">
<input type="checkbox" id="d7-3" class="number3">
<input type="checkbox" id="d7-4" class="number4">
<input type="checkbox" id="d7-5" class="number5">
<input type="checkbox" id="d7-6" class="number6">
<input type="checkbox" id="d7-7" class="number7">
<input type="checkbox" id="d7-8" class="number8">
<input type="checkbox" id="d7-9" class="number9">
<div id="digit8">
<input type="checkbox" id="d8-0" class="number0">
<input type="checkbox" id="d8-1" class="number1">
<input type="checkbox" id="d8-2" class="number2">
<input type="checkbox" id="d8-3" class="number3">
<input type="checkbox" id="d8-4" class="number4">
<input type="checkbox" id="d8-5" class="number5">
<input type="checkbox" id="d8-6" class="number6">
<input type="checkbox" id="d8-7" class="number7">
<input type="checkbox" id="d8-8" class="number8">
<input type="checkbox" id="d8-9" class="number9">
<div id="operations">
<input type="checkbox" id="add">
<input type="checkbox" id="subtract">
<input type="checkbox" id="multiply">
<input type="checkbox" id="divide">
<input type="checkbox" id="equals">
<main>
<div id="screen">
<div id="input"></div>
<div id="output"></div>
</div>
<div id="buttons">
<button type="button">
<label for="d8-7" class="digit8"></label>
<label for="d7-7" class="digit7"></label>
<label for="d6-7" class="digit6"></label>
<label for="d5-7" class="digit5"></label>
<label for="d4-7" class="digit4"></label>
<label for="d3-7" class="digit3"></label>
<label for="d2-7" class="digit2"></label>
<label for="d1-7" class="digit1"></label>
7
</button>
<button type="button">
<label for="d8-8" class="digit8"></label>
<label for="d7-8" class="digit7"></label>
<label for="d6-8" class="digit6"></label>
<label for="d5-8" class="digit5"></label>
<label for="d4-8" class="digit4"></label>
<label for="d3-8" class="digit3"></label>
<label for="d2-8" class="digit2"></label>
<label for="d1-8" class="digit1"></label>
8
</button>
<button type="button">
<label for="d8-9" class="digit8"></label>
<label for="d7-9" class="digit7"></label>
<label for="d6-9" class="digit6"></label>
<label for="d5-9" class="digit5"></label>
<label for="d4-9" class="digit4"></label>
<label for="d3-9" class="digit3"></label>
<label for="d2-9" class="digit2"></label>
<label for="d1-9" class="digit1"></label>
9
</button>
<button type="button"><label for="divide"></label>÷</button>
<button type="button">
<label for="d8-4" class="digit8"></label>
<label for="d7-4" class="digit7"></label>
<label for="d6-4" class="digit6"></label>
<label for="d5-4" class="digit5"></label>
<label for="d4-4" class="digit4"></label>
<label for="d3-4" class="digit3"></label>
<label for="d2-4" class="digit2"></label>
<label for="d1-4" class="digit1"></label>
4
</button>
<button type="button">
<label for="d8-5" class="digit8"></label>
<label for="d7-5" class="digit7"></label>
<label for="d6-5" class="digit6"></label>
<label for="d5-5" class="digit5"></label>
<label for="d4-5" class="digit4"></label>
<label for="d3-5" class="digit3"></label>
<label for="d2-5" class="digit2"></label>
<label for="d1-5" class="digit1"></label>
5
</button>
<button type="button">
<label for="d8-6" class="digit8"></label>
<label for="d7-6" class="digit7"></label>
<label for="d6-6" class="digit6"></label>
<label for="d5-6" class="digit5"></label>
<label for="d4-6" class="digit4"></label>
<label for="d3-6" class="digit3"></label>
<label for="d2-6" class="digit2"></label>
<label for="d1-6" class="digit1"></label>
6
</button>
<button type="button"><label for="multiply"></label>×</button>
<button type="button">
<label for="d8-1" class="digit8"></label>
<label for="d7-1" class="digit7"></label>
<label for="d6-1" class="digit6"></label>
<label for="d5-1" class="digit5"></label>
<label for="d4-1" class="digit4"></label>
<label for="d3-1" class="digit3"></label>
<label for="d2-1" class="digit2"></label>
<label for="d1-1" class="digit1"></label>
1
</button>
<button type="button">
<label for="d8-2" class="digit8"></label>
<label for="d7-2" class="digit7"></label>
<label for="d6-2" class="digit6"></label>
<label for="d5-2" class="digit5"></label>
<label for="d4-2" class="digit4"></label>
<label for="d3-2" class="digit3"></label>
<label for="d2-2" class="digit2"></label>
<label for="d1-2" class="digit1"></label>
2
</button>
<button type="button">
<label for="d8-3" class="digit8"></label>
<label for="d7-3" class="digit7"></label>
<label for="d6-3" class="digit6"></label>
<label for="d5-3" class="digit5"></label>
<label for="d4-3" class="digit4"></label>
<label for="d3-3" class="digit3"></label>
<label for="d2-3" class="digit2"></label>
<label for="d1-3" class="digit1"></label>
3
</button>
<button type="button"><label for="subtract"></label>-</button>
<button type="button"><input type="reset" value="AC"></button>
<button type="button">
<label for="d8-0" class="digit8"></label>
<label for="d7-0" class="digit7"></label>
<label for="d6-0" class="digit6"></label>
<label for="d5-0" class="digit5"></label>
<label for="d4-0" class="digit4"></label>
<label for="d3-0" class="digit3"></label>
<label for="d2-0" class="digit2"></label>
<label for="d1-0" class="digit1"></label>
0
</button>
<button type="button"><label for="equals"></label>=</button>
<button type="button"><label for="add"></label>+</button>
</div>
</main>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</form>
<button id="why">
<svg viewBox="0 0 24 24">
<path d="M11 18h2v-2h-2v2zm1-16C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm0 18c-4.41 0-8-3.59-8-8s3.59-8 8-8 8 3.59 8 8-3.59 8-8 8zm0-14c-2.21 0-4 1.79-4 4h2c0-1.1.9-2 2-2s2 .9 2 2c0 2-3 1.75-3 5h2c0-2.25 3-2.5 3-5 0-2.21-1.79-4-4-4z" style="fill:currentColor;"/>
</svg>
</button>
<section>
<h1>How and why?</h1>
<p>Why? Well, because it is possible. Essentially, I enjoy taking things to extremes and making things that some people might think are not possible.</p>
<p>
How did I do it? Well, it's a mix of using CSS variables, a fitting HTML structure with over 80 checkboxes and labels, calc() for the math, and CSS counters to output things. Have a look at the source code! I promise, there's absolutely zero Javascript. Even this dialog is pure CSS!
</p>
</section>
/* ### LOGIC ################ */
.number9 + * { --digit: 0; }
.number0:checked + * + * + * + * + * + * + * + * + * + * { --digit: 0; }
.number1:checked + * + * + * + * + * + * + * + * + * { --digit: 1; }
.number2:checked + * + * + * + * + * + * + * + * { --digit: 2; }
.number3:checked + * + * + * + * + * + * + * { --digit: 3; }
.number4:checked + * + * + * + * + * + * { --digit: 4; }
.number5:checked + * + * + * + * + * { --digit: 5; }
.number6:checked + * + * + * + * { --digit: 6; }
.number7:checked + * + * + * { --digit: 7; }
.number8:checked + * + * { --digit: 8; }
.number9:checked + * { --digit: 9; }
#digit1 > :checked ~ :last-child { --digit-1: var(--digit); --value-1: var(--digit); }
#digit2 > :checked ~ :last-child { --digit-2: var(--digit); --value-1: calc(var(--digit-1) * 10 + var(--digit-2)); }
#digit3 > :checked ~ :last-child { --digit-3: var(--digit); --value-1: calc(var(--digit-1) * 100 + var(--digit-2) * 10 + var(--digit-3)); }
#digit4 > :checked ~ :last-child { --digit-4: var(--digit); --value-1: calc(var(--digit-1) * 1000 + var(--digit-2) * 100 + var(--digit-3) * 10 + var(--digit-4)); }
#digit5 > :checked ~ :last-child { --digit-5: var(--digit); --value-2: var(--digit-5); }
#digit6 > :checked ~ :last-child { --digit-6: var(--digit); --value-2: calc(var(--digit-5) * 10 + var(--digit-6)); }
#digit7 > :checked ~ :last-child { --digit-7: var(--digit); --value-2: calc(var(--digit-5) * 100 + var(--digit-6) * 10 + var(--digit-7)); }
#digit8 > :checked ~ :last-child { --digit-8: var(--digit); --value-2: calc(var(--digit-5) * 1000 + var(--digit-6) * 100 + var(--digit-7) * 10 + var(--digit-8)); }
#add:checked ~ #equals:checked ~ main { --out: calc(var(--value-1) + var(--value-2)); }
#subtract:checked ~ #equals:checked ~ main { --out: calc(var(--value-1) - var(--value-2)); }
#multiply:checked ~ #equals:checked ~ main { --out: calc(var(--value-1) * var(--value-2)); }
#divide:checked ~ #equals:checked ~ main { --out: calc(var(--value-1) / var(--value-2)); }
main { counter-reset: value1 var(--value-1, 0) value2 var(--value-2, 0) out var(--out, 0); }
/* a
*/
#input::after { content: ""; }
#output::after { content: counter(value1); }
/* a
+
*/
#operations > :checked ~ #equals:not(:checked) ~ main #input::after { content: counter(value1); }
#add:checked ~ #equals:not(:checked) ~ main #output::after { content: "+"; }
#subtract:checked ~ #equals:not(:checked) ~ main #output::after { content: "-"; }
#multiply:checked ~ #equals:not(:checked) ~ main #output::after { content: "\00D7"; }
#divide:checked ~ #equals:not(:checked) ~ main #output::after { content: "\00f7"; }
/* a +
b
*/
#digit5 :checked ~ div #add:checked ~ #equals:not(:checked) ~ main #input::after { content: counter(value1) " + "; }
#digit5 :checked ~ div #subtract:checked ~ #equals:not(:checked) ~ main #input::after { content: counter(value1) " - "; }
#digit5 :checked ~ div #multiply:checked ~ #equals:not(:checked) ~ main #input::after { content: counter(value1) " \00D7 "; }
#digit5 :checked ~ div #divide:checked ~ #equals:not(:checked) ~ main #input::after { content: counter(value1) " \00f7 "; }
#digit5 :checked ~ div #operations > :checked ~ #equals:not(:checked) ~ main #output::after,
#digit5 :checked ~ #operations > :checked ~ #equals:not(:checked) ~ main #output::after { content: counter(value2); }
/* a + b
c
*/
#add:checked ~ #equals:checked ~ main #input::after { content: counter(value1) " + " counter(value2); }
#subtract:checked ~ #equals:checked ~ main #input::after { content: counter(value1) " - " counter(value2); }
#multiply:checked ~ #equals:checked ~ main #input::after { content: counter(value1) " \00D7 " counter(value2); }
#divide:checked ~ #equals:checked ~ main #input::after { content: counter(value1) " \00f7 " counter(value2); }
#equals:checked ~ main #output::after { content: counter(out); }
/* dividing by 0 */
#digit5 > .number0:checked ~ div #divide:checked ~ #equals:checked ~ main #output::after { content: "Oi"; }
#digit5 > .number0:checked ~ div #divide:checked ~ #equals:checked ~ main #output::after { content: "Oi"; }
#digit5 :not(.number0):checked ~ div #divide:checked ~ #equals:checked ~ main #output::after { content: counter(out); }
button {
position: relative;
border: none;
}
label {
width: 100%;
height: 100%;
display: block;
position: absolute;
left: 0;
top: 0;
}
label.digit5,
label.digit6,
label.digit7,
label.digit8 { display: none; }
#operations > :checked ~ main label { display: block; }
#digit1 > :checked ~ div label.digit1 { display: none; }
#digit2 > :checked ~ div label.digit2 { display: none; }
#digit3 > :checked ~ div label.digit3 { display: none; }
#digit4 > :checked ~ div label.digit4 { display: none; }
#digit5 > :checked ~ div label.digit5 { display: none; }
#digit6 > :checked ~ div label.digit6 { display: none; }
#digit7 > :checked ~ div label.digit7 { display: none; }
#digit8 > :checked ~ div label.digit8 { display: none; }
#operations > :checked ~ #equals:not(:checked) ~ main label:nth-child(n + 4) { display: none; }
#operations > :checked ~ #equals:not(:checked) ~ main label.digit5 { display: block; }
#operations > :checked ~ #equals:checked ~ main label { display: none !important; }
#digit5 > :checked ~ div #operations > :checked ~ #equals:not(:checked) ~ main label.digit5 { display: none; }
#digit5 > .number0:checked ~ div #operations > :checked ~ #equals:not(:checked) ~ main label.digit5 { display: block; }
#digit5 > .number0:checked ~ :checked ~ div #operations > :checked ~ #equals:not(:checked) ~ main label.digit5 { display: none; }
label[for=equals]{ display: none; }
#digit5 > :checked ~ div #operations > :checked ~ #equals ~ main label[for=equals]{ display: block; }
#operations > :checked ~ main button:nth-child(4n) label { display: none; }
#digit5 > .number0:checked ~ div main button:nth-child(14) label { pointer-events: none; }
#digit5 > .number0:checked ~ :checked ~ div main button:nth-child(14) label { pointer-events: initial; }
input[type=checkbox]{
position: fixed;
right: 0;
top: 0;
display: block;
width: 1px;
height: 1px;
opacity: 0.01;
transform: scale(0.01);
}
/* ### DESIGN #######################*/
body {
font: 20px / 1.5 Roboto, arial, sans-serif;
height: 100vh;
width: 100vw;
display: flex;
justify-content: center;
align-items: center;
margin: 0;
background-color: khaki;
}
main {
width: 100vw;
max-width: 400px;
height: 100vh;
min-height: 500px;
max-height: 600px;
display: flex;
flex-direction: column;
box-shadow: 0 4px 10px 2px rgba(0, 0, 0, 0.1),
0 5px 20px 5px rgba(0, 0, 0, 0.08),
0 2px 6px rgba(0, 0, 0, 0.1);
background-color: #f7f5eb;
}
#screen {
height: 250px;
text-align: right;
color: rgba(0, 0, 0, 0.7);
}
#input {
height: 50px;
line-height: 50px;
padding: 50px 36px 0;
}
#output {
height: 150px;
line-height: 100px;
padding: 0 36px;
font-size: 80px;
}
#buttons {
flex: 1;
display: grid;
grid-template-columns: repeat(4, 1fr);
grid-template-columns: repeat(4, 1fr);
background-color: #555;
}
button::focus-inner, input::focus-inner { border: 0; }
button {
color: rgba(255, 255, 255, 0.7);
background: none;
font-size: 20px;
font-family: inherit;
outline: none;
padding: 0;
overflow: hidden;
}
button::after {
content: "";
background-color: rgba(255, 255, 255, 0.1);
opacity: 0;
width: 100%;
height: 100%;
position: absolute;
left: 0;
top: 0;
transition: .2s;
pointer-events: none;
}
button:hover::after {
opacity: 1;
}
button::before {
content: "";
background-color: rgba(255, 255, 255, 0.1);
width: 100px;
height: 100px;
border-radius: 50%;
position: absolute;
left: 50%;
top: 50%;
opacity: 0;
transform: translate(-50%, -50%) scale(0.8);
transition: .3s;
animation: .2s 0s 1 bloop;
pointer-events: none;
}
@keyframes bloop{
from { transform: translate(-50%, -50%); opacity: 1; }
to { transform: translate(-50%, -50%) scale(1.6); opacity: 0; }
}
button:active::before {
opacity: 1;
transform: translate(-50%, -50%);
animation: none;
}
button:nth-child(4n){
background-color: #f4e660;
color: rgba(0, 0, 0, 0.6);
}
button:nth-child(4n)::after, button:nth-child(4n)::before{
background-color: rgba(121, 104, 6, 0.1);
}
button, button * {
cursor: pointer;
}
button:nth-child(13){
overflow: visible;
}
button:nth-child(13)::before, button:nth-child(13)::after{
content: none;
}
input[type=reset]{
background: #f4e660;
border: none;
width: 80px;
height: 80px;
border-radius: 50%;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
color: rgba(0, 0, 0, 0.6);
font-size: inherit;
font-family: inherit;
padding: 0;
outline: none;
transition: .2s;
}
input[type=reset]:hover{ background-color: #e7d956; }
input[type=reset]:active { background-color: #dccd4d; }
button#why {
color: rgba(0, 0, 0, 0.3);
width: 40px;
height: 40px;
padding: 16px;
box-sizing: content-box;
position: fixed;
top: 0;
right: 0;
}
button#why::before, button#why::after { content: none; }
section {
font-size: 16px;
width: 450px;
box-sizing: border-box;
position: fixed;
top: 12px;
right: -700px;
max-width: calc(100vw - 24px);
max-height: calc(100vh - 24px);
background-color: white;
transform-origin: 95% 5%;
transform: scale(0.8);
opacity: 0;
box-shadow: 0 4px 10px 2px rgba(0, 0, 0, 0.1),
0 5px 20px 5px rgba(0, 0, 0, 0.08),
0 10px 30px 10px rgba(0, 0, 0, 0.08);
transition: all .3s, right 0s .3s;
background-color: #f7f5eb;
padding: 2em;
}
button#why:focus + section {
right: 12px;
transform: none;
opacity: 1;
transition: all .3s, right 0s;
}
section h1 {
padding-left: 24px;
font-size: 2em;
margin: 0 auto 40px;
}
section p { margin: 18px 0; }
section p:last-child { margin-bottom: 12px; }
a {
color: rgba(0, 0, 0, 0.25);
width: 48px;
height: 48px;
padding: 12px;
position: fixed;
top: 0;
left: 0;
}
svg {
display: block;
width: 100%;
height: 100%;
}
@media screen and (max-width: 600px){
main {
max-width: none;
max-height: none;
}
button#why, a {
padding: 12px;
width: 36px;
height: 36px;
}
}
@media screen and (max-height: 500px){
section { width: 900px; }
}
External CSS
This Pen doesn't use any external CSS resources.
External JavaScript
This Pen doesn't use any external JavaScript resources.