style.css

:root {
  --white-alpha-40: rgba(255, 255, 255, 0.4);
  --white-alpha-25: rgba(255, 255, 255, 0.25);
}

* {
  margin: 0;
  padding: 0;
  font-family: "Poppins", sans-serif;
  box-sizing: border-box;
}

/* Animation Keyframes */

@keyframes fadeOut {
  0% {
    opacity: 1;
  }

  100% {
    opacity: 0;
  }
}

@keyframes zoomInOut {
  0%,
  100% {
    transform: scale(0.5);
  }

  50% {
    transform: scale(1);
  }
}

@keyframes bounceTop {
  0%,
  100% {
    transform: translateY(-50px);
  }

  50% {
    transform: translateY(0px);
  }
}

/* **** Background Circles ****  */

.bg-circles div {
  position: absolute;
  border-radius: 50%;
}

.bg-circles .circle-1 {
  height: 80px;
  width: 80px;
  background-color: blue;
  left: 10%;
  top: 20%;
  opacity: 0.3;
  filter: blur(10px);
  animation: bounceTop 5s ease-in-out infinite;
}

.bg-circles .circle-2 {
  height: 150px;
  width: 150px;
  background-color: #cc2b5e;
  left: 29%;
  top: 60%;
  opacity: 0.4;
  filter: blur(10px);
  animation: zoomInOut 8s linear infinite;
}

.bg-circles .circle-3 {
  height: 150px;
  width: 150px;
  background-color: #57bacd;
  right: 28%;
  top: 15%;
  opacity: 0.6;
  filter: blur(10px);
  animation: zoomInOut 8s linear infinite;
}

.bg-circles .circle-4 {
  height: 80px;
  width: 80px;
  background-color: red;
  right: 10%;
  top: 80%;
  opacity: 0.6;
  filter: blur(10px);
  animation: bounceTop 8s linear infinite;
}

.container {
  width: 100%;
  min-height: 100vh;
  /* background: linear-gradient(135deg, #fbc2eb 0%, #a6c1ee 100%); */
  background: linear-gradient(45deg, #f3e7e9 0%, #e3eeff 99%, #e3eeff 100%);

  padding: 10px;
}

.todo-app {
  width: 100%;
  max-width: 540px;
  background-color: var(--white-alpha-25);
  border: 1px solid var(--white-alpha-40);
  margin: 100px auto 20px;
  padding: 40px 30px 70px;
  border-radius: 10px;
  box-shadow: 5px 5px 25px 5px rgba(110, 104, 104, 0.7);
}

.todo-app h2 {
  color: #cc2b5e;
  display: flex;
  font-size: 30px;
  align-items: center;
  margin-bottom: 50px;
}

.todo-app h2 img {
  width: 40px;
  margin-right: 10px;
}

.row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #f3e7e9;
  border-radius: 10px;
  padding-left: 20px;
  margin-bottom: 25px;
}

input {
  flex: 1;
  border: none;
  outline: none;
  color: #333333;
  background: transparent;
  padding: 10px;
  font-weight: 14px;
  border-radius: 6px;
  transition: background-color 0.3s ease;
}

button {
  border: none;
  outline: none;
  padding: 16px 50px;
  background: #b296d9;
  color: #fff;
  font-size: 18px;
  font-weight: 600;
  cursor: pointer;
  border-radius: 10px;
}

button:hover {
  background-color: #9d80cc;
  color: #fff;
}

ul li {
  list-style: none;
  font-size: 17px;
  padding: 12px 8px 12px 50px;
  user-select: none;
  cursor: pointer;
  position: relative;
}

ul li::before {
  content: "";
  position: absolute;
  height: 28px;
  width: 28px;
  border-radius: 50px;
  background-image: url("images/icon.png");
  background-size: cover;
  background-position: center;
  top: 7px;
  left: 8px;
}

ul li.checked {
  color: #555;
  text-decoration: line-through;
}

ul li.checked::before {
  background-image: url("images/check.png");
  height: 50px;
  width: 50px;
  margin-top: -8px;
  margin-left: -10px;
}

ul li span {
  position: absolute;
  right: 0;
  top: 5px;
  width: 40px;
  height: 40px;
  font-size: 22px;
  color: #555;
  line-height: 40px;
  text-align: center;
}

ul li span:hover {
  /* background: #edeef0; */
  background: #f5d0d0;
}

/* Responsive Design  */

@media (max-width: 760px) {
  .container {
    height: 100%;
    width: 100%;
  }

  .row {
    max-width: 400px;
  }

  button {
    max-width: 400px;
    padding: 10px;
    font-size: 15px;
  }
}