* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, Helvetica, sans-serif;
}
:root {
  --container-color: #3b4664;
  --theme-but-color: #252c44;
  --text-color: #eae3db;
  --text-area-color: #181f32;
  --but-text-color: #4d525d;
  --reset-but-color: #a2b3e1;
  --reset-but-shadow-color: #414e70;
  --equal-but-color: #f96c5b;
  --equal-but-shadow-color: #8f2316;
  --numbers-but-color: #eee;
  --numbers-shadow-color: #b0a296;
}
body {
  background-color: var(--container-color);
  height: 100vh;
}
.app {
  margin: 50px auto;
  padding: 30px;
  width: 500px;
  height: 600px;
  font-weight: bold;
}

.app .theme {
  background-color: transparent;
  color: var(--text-area-color);
  display: flex;
  justify-content: space-between;
  width: 400px;
  color: var(--text-color);
}
.app .theme h3 {
  font-weight: bold;
}
.app .theme .left {
  display: flex;
  align-items: center;
  gap: 10px;
  justify-content: space-between;
}
.app .theme .left h4 {
  font-size: 12px;
}
.app .theme .left .theme-cont {
  width: 78px;
  height: 18px;
  border-radius: 50px;
  background-color: var(--text-area-color);
  position: relative;
  cursor: pointer;
}
.app .theme .left .theme-cont .ball {
  width: 18px;
  position: absolute;
  height: 97%;
  border-radius: 50%;
  background-color: var(--equal-but-color);
  left: 1px;
  transition: 0.3s;
}
.output {
  width: 96%;
  height: 74px;
  background-color: var(--text-area-color);
  margin: 20px -7px;
  border-radius: 9px;
  display: flex;
  position: relative;
}

.buttoms-container {
  width: 93%;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  padding: 10px;
  background-color: var(--text-area-color);
  border-radius: 12px;
  text-align: center;
}
.buttoms-container button {
  padding: 10px;
  font-size: 20px;
  border: none;
  border-radius: 10px;
  width: 75px;
  box-shadow: 0px 3px var(--numbers-shadow-color);
  cursor: pointer;
  background-color: var(--numbers-but-color);
  color: var(--but-text-color);
}
.buttoms-container button.del {
  background-color: var(--reset-but-color);
  color: var(--text-color);
  box-shadow: 0px 3px var(--reset-but-shadow-color);
}
.buttoms-container > div {
  display: flex;
  margin-bottom: 10px;
  gap: 26px;
  margin-left: 4px;
}
.buttoms-container .last {
  gap: 23px;
  justify-content: space-around;
  color: white;
}
.buttoms-container .last button {
  width: 49%;
  color: var();
}
.buttoms-container .last .rest {
  background-color: var(--reset-but-color);
  color: var(--text-color);
  box-shadow: 0px 3px var(--reset-but-shadow-color);
}
.buttoms-container .last .equal {
  background-color: var(--equal-but-color);
  color: var(--text-color);
  box-shadow: 0px 2px var(--equal-but-shadow-color);
}
.number {
  color: var(--numbers-but-color);
  display: flex;
  align-items: center;
  font-size: 25px;
  font-weight: normal;
  margin-left: 4px;
  position: absolute;
  right: 9px;
  top: 50%;
  transform: translateY(-50%);
}

/*’Media Query*/
@media (max-width: 515px) {
  .app {
    width: 100%;
  }
  .app .theme {
    width: 95%;
  }
  .app .theme .left .theme-cont {
    width: 65px;
  }
  .app .theme .left .theme-cont .ball {
    width: 17px;
    height: 100%;
    left: 0;
  }
  .output {
    width: 102%;
  }
  .buttoms-container {
    width: 103%;
    height: 40vh;
    margin-top: 40px;
    margin-left: -6px;
  }
  .buttoms-container > div {
    margin-top: 14px;
  }

  .buttoms-container .last {
    margin-top: 22px;
  }
}