@import url('https://fonts.googleapis.com/css2?family=Comfortaa:wght@400;500&display=swap');

* {
  box-sizing: border-box;
}

:root {
  font-family: 'Comfortaa', cursive;
}

body {
  --bg-color: #f3f4f4;
  --link-color: #7c7f8e;
  --link-hover-color: #242a37;
  --link-active-1: #ff4350;
  --wrapper-bg: #fff;
  --box-shadow: 0px 0px 10px 6px rgba(235,235,235,.6);
  
  margin: 0;
  width: 100%;
  height: 100vh;
  background-color: #f3f4f4;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background-color: var(--bg-color);
  transition: background .3s ease-in;
}

body.dark {
  --bg-color: #333a48;
  --link-color: #b0b4c7;
  --link-hover-color: #b5bbd0;
  --link-active-1: #ff4350;
  --wrapper-bg: #242a37;
  --box-shadow: 0px 0px 8px 0px #282b33;
}

.wrapper {
  background-color: var(--wrapper-bg);
  padding: 0 40px;
  flex-shrink: 0;
  border-radius: 6px;
  box-shadow: var(--box-shadow);
  height: 60px;
  display: flex;
  align-items: center;
  transition: all .3s ease-in;
}

.item-link {
  position: relative;
  display: flex;
  align-items: center;
  color: #7c7f8e;
  text-decoration: none;
  padding: 18px 0;
  margin: 0 10px;
  letter-spacing: .5px;
  
  &:before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    height: 4px;
    background-color: var(--link-hover-color);
    z-index: 2;
    width: 0;
    border-radius: 2px;
    transition: width 0.4s cubic-bezier(0.22, 0.61, 0.36, 1);
  }
  
  &:not(.active):hover:before {
    width: 100%;
    opacity: 1;
  }
  
  &:not(.active):hover {
    color: var(--link-hover-color);
  }
  
  &.active:before { width: 100%; }
}

.active:first-child {
  color: var(--link-active-1);
  
  &:before { background-color: var(--link-active-1); }
  
  svg {
    transition: all .2s ease-in;
    transform: scale(1.1);
  }
}

.active:nth-child(2){
  color: #fbb046;
  
  &:before { background-color: #fbb046; }
  
  svg circle {
    animation: headbang .3s ease-in both;
  }
}

@keyframes headbang {
  0% { transform: translate3d(0, 0, 0); }
  25% { transform: translate3d(2px, 0 , 0); }
  50% { transform: translate3d(0, 0 , 0); }
  75% { transform: translate3d(-2px, 0, 0);}
  100% { transform: translate3d(0 , 0, 0); }
}

.active:nth-child(3){
  color: #47caa4;
  
  &:before { background-color: #47caa4; }
  
  svg path {
    animation: shake .6s cubic-bezier(.36,.07,.19,.97) both;
  }
  
  svg path:nth-child(2) {
    animation-delay: .1s;
  }
}

@keyframes shake {
  10%, 90% {
    transform: translate3d(-1px, 0, 0);
  }
  20%, 80% {
    transform: translate3d(2px, 0, 0);
  }

  30%, 50%, 70% {
    transform: translate3d(-4px, 0, 0);
  }

  40%, 60% {
    transform: translate3d(4px, 0, 0);
  }
}

.active:nth-child(4){
  color: #495fcc;
  
  &:before { background-color: #495fcc; }
  
  svg {
    transition: .3s ease-in-out;
    transform: rotate(360deg);
  }
}

.link-icon {
  width: 20px;
  height: 18px;
  margin-right: 4px;
  flex-grow: 0;
}

.switch-mode {
  position: absolute;
  top: 20px;
  right: 20px;
  background-color: transparent;
  border: none;
  color: #ddd;
  outline: none;
  cursor: pointer;
  
  svg {
    width:0;
    height: 24px;
    transition: all .3s ease-in;
    transform-origin: center;
  }
  
  .moon { opacity: 0; }
  .sun { width: 24px; }
}

.dark .moon {
  opacity: 1;
  width: 24px;
}

.dark .sun {
  opacity: 0;
  width: 0;
}

@media screen and (max-width: 580px) {
  .wrapper {
    transform: scale(.8);
  }
  
  .switch-mode {
    right: 8px;
  }
}

@media screen and (max-width: 520px) {
  .wrapper {
    transform: scale(.6);
  }
}