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

.container {
  width: 100%;
  min-height: 100vh;
  background: linear-gradient(132deg, #153677, #4e085f);
  padding: 10px;
}

#clock {
  font-size: 2rem;
  font-family: "Courier New", Courier, monospace;
  color: #002765;
  max-width: 540px;
  background: #fff;
  border-radius: 10px;
}

.todo-app {
  width: 100%;
  max-width: 540px;
  background: #fff;
  margin: 100px auto 20px;
  padding: 40px 30px 70px;
  border-radius: 10px;
}

.todo-app h2 {
  color: #002765;
  display: flex;
  align-items: center;
  margin-bottom: 20px;
}

.todo-app h2 img {
  width: 30px;
  margin-left: 10px;
}

.row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #edeef0;
  border-radius: 30px;
  padding-left: 20px;
  margin-bottom: 25px;
}

input {
  flex: 1;
  border: none;
  outline: none;
  background: transparent;
  padding: 10px;
  font-weight: 14px;
}

button {
  border: none;
  outline: none;
  padding: 16px 50px;
  background: #ff5945;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
  border-radius: 40px;
}

ul li {
  list-style: none;
  font-size: 17px;
  padding: 16px 8px 12px 50px;
  user-select: none;
  cursor: pointer;
  position: relative;
}

ul li::before {
  content: "";
  position: absolute;
  height: 28px;
  width: 28px;
  border-radius: 50%;
  background-image: url(img/unchecked.png);
  background-size: cover;
  background-position: center;
  top: 12px;
  left: 8px;
}

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

ul li.checked::before {
  background-image: url(img/checked.png);
}

ul li span {
  position: absolute;
  right: 0;
  top: 5px;
  width: 40px;
  height: 40px;
  font-size: 22px;
  color: #555;
  line-height: 40px;
  text-align: center;
  border-radius: 50%;
}

ul li span:hover {
  background: #edeef0;
}

.toast {
  position: fixed;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, #ff6b6b, #ee5a24);
  color: white;
  padding: 15px 25px;
  border-radius: 8px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
  font-size: 16px;
  font-weight: 500;
  z-index: 1000;
  transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  display: flex;
  align-items: center;
  gap: 10px;
}

.toast.show {
  top: 20px;
  animation: shake 0.5s ease-in-out 0.2s;
}

.toast::before {
  content: "⚠️";
  font-size: 18px;
}

@keyframes shake {
  0%,
  100% {
    transform: translateX(-50%) rotate(0deg);
  }
  25% {
    transform: translateX(-50%) rotate(-2deg);
  }
  75% {
    transform: translateX(-50%) rotate(2deg);
  }
}

.backbutton {
  display: block;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  position: fixed;
  bottom: 0;
  right: 0;
  margin-right: 200px;
  margin-bottom: 200px;
}

.backbutton a {
  text-decoration: none;
  color: white;
  border-radius: 5px;
  font-size: 16px;
}

@media screen and (max-width: 700px) {
  .backbutton {
    margin-right: 20px;
    margin-bottom: 20px;
  }
}