HTML

  <button id="btn1" class="btn-1"><span>zornet.ru</span></button>
    <button id="btn2" class="btn-2"><span>zornet.ru</span></button>
    <button id="btn3" class="btn-3"><span>zornet.ru</span></button>
    <button id="btn4" class="btn-4"><span>zornet.ru</span></button>
    <button id="btn5" class="btn-5"><span>zornet.ru</span></button>
    <button id="btn6" class="btn-6"><span>zornet.ru</span></button>
    <button id="btn7" class="btn-7"><span>zornet.ru</span></button>
    <button id="btn8" class="btn-8"><span>zornet.ru</span></button>
    <button id="btn9" class="btn-9"><span>zornet.ru</span></button>
    <button id="btn10" class="btn-10"><span>zornet.ru</span></button>
    <button id="btn11" class="btn-11"><span>zornet.ru</span></button>
    <button id="btn12" class="btn-12"><span>zornet.ru</span></button>
    <button id="btn13" class="btn-13"><span>zornet.ru</span></button>
    <button id="btn14" class="btn-14"><span>zornet.ru</span></button>
    <button id="btn15" class="btn-15"><span>zornet.ru</span></button>
    <button id="btn16" class="btn-16"><span>zornet.ru</span></button>
    <button id="btn17" class="btn-17"><span>zornet.ru</span></button>
    <button id="btn18" class="btn-18"><span>zornet.ru</span></button>
    <button id="btn19" class="btn-19"><span>zornet.ru</span></button>
    <button id="btn20" class="btn-20"><span>zornet.ru</span></button>
    <button id="btn21" class="btn-21"><span>zornet.ru</span></button>
    <button id="btn22" class="btn-22"><span>zornet.ru</span></button>
    <button id="btn23" class="btn-23"><span>zornet.ru</span></button>
    <button id="btn24" class="btn-24"><span>zornet.ru</span></button>
    <button id="btn25" class="btn-25"><span>zornet.ru</span></button>
    <button id="btn26" class="btn-26"><span>zornet.ru</span></button>
    <button id="btn27" class="btn-27"><span>zornet.ru</span></button>
    <button id="btn28" class="btn-28"><span>zornet.ru</span></button>
  </div>

CSS

button {
  cursor: pointer;
  letter-spacing: 2px;
  text-transform: uppercase;
  font-family: Marvel;
  font-size: 20pt;
  width: 200px;
  height: 45px;
  position: relative;
  border: solid #bbb 2px;
  color: #bbb;
  z-index: 1;
  transition: all 0.5s ease-in-out;
  border-radius: 5px;
  margin: 5px;
}
button:focus {
  outline: none;
}
.button-container {
  width: 852px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 0px;
}
h4 {
  padding: 0px;
  line-height: .1;
  margin: 13px;
}
a {
  color: red;
  text-decoration: none;
  background: #f1f1f1;
  padding-left: 5px;
  padding-right: 5px;
  border-radius: 15px;
  transition: all 0.3s ease-in-out;
}
a:hover {
  color: #f1f1f1;
  background-color: red
}
#footer {
  position: relative;
  top: 4px;
  padding-bottom: 0px;
  text-align: center;
  font-family: Marvel;
  font-size: 13pt;
  color: #f1f1f1;
  line-height: 1;
  width: 99%;
}
@media screen and (max-width: 880px) {
  .button-container {
    width: 424px;
  }
}
@media screen and (max-width: 445px) {
  .button-container {
    width: 200px;
  }
}

.btn-1 {
  background: #333;
  padding: 0;
}
.btn-1 span {
  position: relative;
  display: block;
  width: 100%;
  height: 100%;
  padding-top: 5px;
  transition: 0.5s ease-in-out;
}
.btn-1:before,
.btn-1:after {
  position: absolute;
  content: "";
  right: 0;
  bottom: 0;
  background: red;
  transition: all 0.5s ease-in-out;
}
.btn-1:before {
  height: 0%;
  width: 2px;
  top: 50%;
}
.btn-1:after {
  width: 0%;
  height: 2px;
  left: 50%;
}
.btn-1:hover:before {
  height: 100%;
  top: 0%;
  background: red;
}
.btn-1:hover:after {
  width: 100%;
  left: 0%;
  background: red;
}
.btn-1:hover {
  background: transparent;
  border-color: #333;
}
.btn-1 span:hover {
  color: red;
}
.btn-1 span:before,
.btn-1 span:after {
  position: absolute;
  content: "";
  left: 0;
  top: 0;
  background: #333;
  transition: all 0.5s ease-in-out;
}
.btn-1 span:before {
  width: 2px;
  height: 0%;
  top: 50%;
}
.btn-1 span:after {
  height: 2px;
  width: 0%;
  left: 50%;
}
.btn-1 span:hover:before {
  height: 41px;
  top: 0%;
  background: red;
}
.btn-1 span:hover:after {
  width: 100%;
  left: 0%;
  background: red;
}
.btn-1:active {
  background-color: #00a7fc;
  border-color: #00a7fc;
}
.btn-1:active:before,
.btn-1:active:after {
  background-color: #00a7fc;
}
.btn-1 span:active {
  color: #333;
}
.btn-1 span:active:before,
.btn-1 span:active:after {
  background-color: #00a7fc;
}


.btn-2 {
  background-image: -webkit-linear-gradient(30deg, transparent 50%, red 50%);
  background-image: linear-gradient(30deg, transparent 50%, red 50%);
  background-size: 298%;
  background-color: transparent;
  background-repeat: no-repeat;
  background-position: 0%;
}
.btn-2:hover {
  background-position: 100%;
  color: #f1f1f1;
  border-color: red;
}
.btn-2:active {
  background-color: #00a7fc;
  color: #333;
  background-position: 0%;
  border-color: #00a7fc;
}


.btn-3 {
  background: #333;
}
.btn-3:before {
  content: "";
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  background: red;
  transform: scale(0);
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-3:hover:before {
  transform: scale(1);
}
.btn-3:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-3:active:before {
  background-color: #00a7fc;
}
.btn-3:active {
  border-color: #00a7fc;
  color: #333;
  background-color: #00a7fc;
}


.btn-4 {
  background: red;
}
.btn-4:before {
  content: "";
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  background-color: #333;
  transform: scale(1);
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-4:hover:before {
  transform: scale(0);
}
.btn-4:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-4:active {
  border-color: #00a7fc;
  color: #333;
  background-color: #00a7fc;
}
.btn-4:active:before {
  background-color: #00a7fc;
}


.btn-5 {
  background: #333;
}
.btn-5:before {
  content: "";
  width: 0%;
  height: 100%;
  position: absolute;
  top: 0;
  right: 0;
  background-color: red;
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-5:hover:before {
  width: 100%;
}
.btn-5:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-5:active:before {
  background-color: #00a7fc;
}
.btn-5:active {
  border-color: #00a7fc;
  background-color: #00a7fc;
  color: #333;
}


.btn-6 {
  background: #333;
}
.btn-6:before {
  content: "";
  width: 0%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  background-color: red;
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-6:hover:before {
  width: 100%;
}
.btn-6:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-6:active:before {
  background-color: #00a7fc;
}
.btn-6:active {
  border-color: #00a7fc;
  background-color: #00a7fc;
  color: #333;
}


.btn-7 {
  background: #333;
}
.btn-7:before {
  content: "";
  width: 100%;
  height: 0%;
  position: absolute;
  top: 0;
  right: 0;
  background-color: red;
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-7:hover:before {
  height: 100%;
}
.btn-7:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-7:active:before {
  background-color: #00a7fc;
}
.btn-7:active {
  border-color: #00a7fc;
  background-color: #00a7fc;
  color: #333;
}


.btn-8 {
  background: #333;
}
.btn-8:before {
  content: "";
  width: 100%;
  height: 0%;
  position: absolute;
  bottom: 0;
  right: 0;
  background-color: red;
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-8:hover:before {
  height: 100%;
}
.btn-8:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-8:active:before {
  background-color: #00a7fc;
}
.btn-8:active {
  border-color: #00a7fc;
  background-color: #00a7fc;
  color: #333;
}


.btn-9 {
  background: #333;
}
.btn-9:before {
  content: "";
  width: 0%;
  height: 100%;
  position: absolute;
  top: 0;
  right: 50%;
  background-color: red;
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-9:hover:before {
  width: 100%;
  right: 0%;
}
.btn-9:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-9:active {
  color: #333;
  border-color: #00a7fc;
  background-color: #00a7fc;
}
.btn-9:active:before {
  background-color: #00a7fc;
}


.btn-10 {
  background: red;
}
.btn-10:before {
  content: "";
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  right: 0%;
  background-color: #333;
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-10:hover:before {
  width: 0%;
  right: 50%;
}
.btn-10:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-10:active {
  color: #333;
  border-color: #00a7fc;
  background-color: #00a7fc;
}
.btn-10:active:before {
  background-color: #00a7fc;
}


.btn-11 {
  background: #333;
}
.btn-11:before {
  content: "";
  width: 100%;
  height: 0%;
  position: absolute;
  top: 50%;
  right: 0%;
  background-color: red;
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-11:hover:before {
  height: 100%;
  top: 0%;
}
.btn-11:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-11:active {
  color: #333;
  border-color: #00a7fc;
  background-color: #00a7fc;
}
.btn-11:active:before {
  background-color: #00a7fc;
}


.btn-12 {
  background: red;
}
.btn-12:before {
  content: "";
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0%;
  right: 0%;
  background-color: #333;
  transition: 0.5s ease-in-out;
  z-index: -1;
}
.btn-12:hover:before {
  height: 0%;
  top: 50%;
}
.btn-12:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-12:active {
  color: #333;
  border-color: #00a7fc;
  background-color: #00a7fc;
}
.btn-12:active:before {
  background-color: #00a7fc;
}


.btn-13 {
  background-color: #333;
}
.btn-13:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-13:hover:before {
  left: 0%;
  right: auto;
  width: 100%;
}
.btn-13:before {
  position: absolute;
  top: 0px;
  right: 0px;
  width: 0%;
  height: 100%;
  z-index: -1;
  content: "";
  color: #f1f1f1;
  background: red;
  transition: all 500ms ease-in-out;
}
.btn-13:active:before {
  background-color: #00a7fc;
}
.btn-13:active {
  color: #333;
  background-color: #00a7fc;
  border-color: #00a7fc;
}


.btn-14 {
  background-color: #333;
}
.btn-14:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-14:hover:before {
  right: 0%;
  left: auto;
  width: 100%;
}
.btn-14:before {
  position: absolute;
  top: 0px;
  left: 0px;
  width: 0%;
  height: 100%;
  z-index: -1;
  content: "";
  color: #f1f1f1;
  background: red;
  transition: all 500ms ease-in-out;
}
.btn-14:active:before {
  background-color: #00a7fc;
}
.btn-14:active {
  color: #333;
  background-color: #00a7fc;
  border-color: #00a7fc;
}


.btn-15 {
  background-color: #333;
}
.btn-15:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-15:hover:before {
  bottom: 0%;
  top: auto;
  height: 100%;
}
.btn-15:before {
  position: absolute;
  top: 0px;
  left: 0px;
  height: 0%;
  width: 100%;
  z-index: -1;
  content: "";
  color: #f1f1f1;
  background: red;
  transition: all 500ms ease-in-out;
}
.btn-15:active:before {
  background-color: #00a7fc;
}
.btn-15:active {
  color: #333;
  background-color: #00a7fc;
  border-color: #00a7fc;
}


.btn-16 {
  background-color: #333;
}
.btn-16:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-16:hover:before {
  top: 0%;
  bottom: auto;
  height: 100%;
}
.btn-16:before {
  position: absolute;
  bottom: 0px;
  left: 0px;
  height: 0%;
  width: 100%;
  z-index: -1;
  content: "";
  color: #f1f1f1;
  background: red;
  transition: all 500ms ease-in-out;
}
.btn-16:active:before {
  background-color: #00a7fc;
}
.btn-16:active {
  color: #333;
  background-color: #00a7fc;
  border-color: #00a7fc;
}


.btn-17 {
  background: #333;
  overflow: hidden;
  transition: all 0.3s ease-in-out 0s;
}
.btn-17:before {
  content: "";
  height: 0%;
  width: 0%;
  background: red;
  position: absolute;
  top: 50%;
  right: 50%;
  border-radius: 20px;
  z-index: -1;
  -webkit-transition: all 0.5s ease;
  -moz-transition: all 0.5s ease;
  -ms-transition: all 0.5s ease;
  transform: translateX(50%) translateY(-50%) rotate(-45deg);
}
.btn-17:hover:before {
  animation: btn-17 2s;
  background-color: red;
}
.btn-17:hover {
  color: #f1f1f1;
  border-color: red;
  background-color: red;
  transition: background-color 0.5s ease-in-out 0.8s;
}
@keyframes btn-17 {
  0% {
    height: 0%;
    width: 0%;
  }
  25% {
    height: 250%;
    width: 600%;
  }
  50% {
    height: 600%;
    width: 600%;
  }
  75% {
    height: 100%;
    width: 600%;
  }
  100% {
    height: 0%;
    width: 0%;
  }
}


.btn-18 {
  background: #333;
  overflow: hidden;
  transition: all 0.3s ease-in-out 0s;
}
.btn-18:before {
  content: "";
  height: 0%;
  width: 0%;
  background: red;
  position: absolute;
  top: 50%;
  right: 50%;
  border-radius: 20px;
  z-index: -1;
  -webkit-transition: all 0.5s ease;
  -moz-transition: all 0.5s ease;
  -ms-transition: all 0.5s ease;
  transform: translateX(50%) translateY(-50%) rotate(45deg);
}
.btn-18:hover:before {
  animation: btn-18 2s;
  background-color: red;
}
.btn-18:hover {
  color: #f1f1f1;
  border-color: red;
  background-color: red;
  transition: background-color 0.5s ease-in-out 0.8s;
}
@keyframes btn-18 {
  0% {
    height: 0%;
    width: 0%;
  }
  25% {
    height: 250%;
    width: 600%;
  }
  50% {
    height: 600%;
    width: 600%;
  }
  75% {
    height: 100%;
    width: 600%;
  }
  100% {
    height: 0%;
    width: 0%;
  }
}


.btn-19 {
  overflow: hidden;
  background: #333;
}
.btn-19:before {
  content: "";
  position: absolute;
  background: red;
  width: 0%;
  height: 0%;
  border-radius: 50%;
  z-index: -1;
  top: 50%;
  left: 50%;
  transform: translateX(-50%) translateY(-50%);
  -webkit-transition: all 0.5s ease;
  -moz-transition: all 1s ease;
  -ms-transition: all 1s ease;
}
.btn-19:hover:before {
  width: 110%;
  height: 300px;
}
.btn-19:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-19:active:before {
  background-color: #00a7fc;
}
.btn-19:active {
  color: #333;
  background-color: #00a7fc;
  border-color: #00a7fc;
}


.btn-20 {
  overflow: hidden;
  background-color: red;
}
.btn-20:before {
  content: "";
  position: absolute;
  background: #333;
  width: 110%;
  height: 300px;
  border-radius: 50%;
  z-index: -1;
  top: 50%;
  left: 50%;
  transform: translateX(-50%) translateY(-50%);
  -webkit-transition: all 0.5s ease;
  -moz-transition: all 1s ease;
  -ms-transition: all 1s ease;
}
.btn-20:hover:before {
  width: 0%;
  height: 0%;
}
.btn-20:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-20:active:before {
  background-color: #00a7fc;
}
.btn-20:active {
  color: #333;
  background-color: #00a7fc;
  border-color: #00a7fc;
}


.btn-21 {
  cursor: pointer;
  letter-spacing: 2px;
  text-transform: uppercase;
  font-family: Marvel;
  font-size: 20pt;
  width: 200px;
  height: 45px;
  position: relative;
  color: #bbb;
  z-index: 1;
  transition: all 0.5s ease-in-out;
  border-radius: 0px;
  margin: 5px;
  background: transparent;
  padding: 0;
  overflow: hidden;
  border: none;
}
.btn-21:before {
  content: "";
  position: absolute;
  bottom: 0;
  right: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(to left, transparent, #bbb);
  animation: btn-21-left 2s linear infinite;
  transition: 0.5s ease-in-out;
}
.btn-21:after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 2px;
  height: 100%;
  background: linear-gradient(to top, transparent, #bbb);
  animation: btn-21-top 2s linear infinite;
  animation-delay: 1s;
  transform: translateY(-100%);
}
.btn-21 span {
  position: relative;
  display: block;
  width: 100%;
  height: 100%;
  padding: 6px;
}
.btn-21 span:after {
  content: "";
  position: absolute;
  top: 0px;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(to right, transparent, #bbb);
  animation: btn-21-right 2s linear infinite;
}
.btn-21 span:before {
  content: "";
  position: absolute;
  top: 0px;
  right: 12px;
  width: 2px;
  height: 100%;
  background: linear-gradient(to bottom, transparent, #bbb);
  animation: btn-22-bottom 2s linear infinite;
  animation-delay: 1s;
  transform: translateY(-100%)
}
.btn-21:hover:before {
  background: linear-gradient(to left, transparent, red);
}
.btn-21:hover:after {
  background: linear-gradient(to top, transparent, red);
}
.btn-21 span:hover:before {
  background: linear-gradient(to bottom, transparent, red);
}
.btn-21 span:hover:after {
  background: linear-gradient(to right, transparent, red);
}
.btn-21:hover {
  color: red;
}
.btn-21:active:before {
  background: linear-gradient(to left, transparent, #00a7fc);
}
.btn-21:active:after {
  background: linear-gradient(to top, transparent, #00a7fc);
}
.btn-21 span:active:before {
  background: linear-gradient(to bottom, transparent, #00a7fc);
}
.btn-21 span:active:after {
  background: linear-gradient(to right, transparent, #00a7fc);
}
.btn-21:active {
  color: #00a7fc;
}
@keyframes btn-21-top {
  0% {
    transform: translateY(100%);
  }
  100% {
    transform: translateY(-100%);
  }
}
@keyframes btn-21-left {
  0% {
    transform: translateX(100%);
  }
  100% {
    transform: translateX(-100%);
  }
}
@keyframes btn-21-bottom {
  0% {
    transform: translateY(-100%);
  }
  100% {
    transform: translateY(100%);
  }
}
@keyframes btn-21-right {
  0% {
    transform: translateX(-100%);
  }
  100% {
    transform: translateX(100%);
  }
}


.btn-22 {
  cursor: pointer;
  letter-spacing: 2px;
  text-transform: uppercase;
  font-family: Marvel;
  font-size: 20pt;
  width: 200px;
  height: 45px;
  position: relative;
  color: #bbb;
  z-index: 1;
  transition: all 0.5s ease-in-out;
  border-radius: 0px;
  margin: 5px;
  background: transparent;
  padding: 0;
  overflow: hidden;
  border: none;
}
.btn-22:before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(to left, transparent, #bbb);
  animation: btn-22-left 2s linear infinite;
  transition: 0.5s ease-in-out;
}
.btn-22:after {
  content: "";
  position: absolute;
  bottom: 0;
  right: 0;
  width: 2px;
  height: 100%;
  background: linear-gradient(to top, transparent, #bbb);
  animation: btn-22-top 2s linear infinite;
  animation-delay: 1s;
  transform: translateY(-100%);
}
.btn-22 span {
  position: relative;
  display: block;
  width: 100%;
  height: 100%;
  padding: 6px;
}
.btn-22 span:after {
  content: "";
  position: absolute;
  bottom: 12px;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(to right, transparent, #bbb);
  animation: btn-22-right 2s linear infinite;
}
.btn-22 span:before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 2px;
  height: 100%;
  background: linear-gradient(to bottom, transparent, #bbb);
  animation: btn-22-bottom 2s linear infinite;
  animation-delay: 1s;
  transform: translateY(-100%)
}
.btn-22:hover:before {
  background: linear-gradient(to left, transparent, red);
}
.btn-22:hover:after {
  background: linear-gradient(to top, transparent, red);
}
.btn-22 span:hover:before {
  background: linear-gradient(to bottom, transparent, red);
}
.btn-22 span:hover:after {
  background: linear-gradient(to right, transparent, red);
}
.btn-22:hover {
  color: red;
}
.btn-22:active:before {
  background: linear-gradient(to left, transparent, #00a7fc);
}
.btn-22:active:after {
  background: linear-gradient(to top, transparent, #00a7fc);
}
.btn-22 span:active:before {
  background: linear-gradient(to bottom, transparent, #00a7fc);
}
.btn-22 span:active:after {
  background: linear-gradient(to right, transparent, #00a7fc);
}
.btn-22:active {
  color: #00a7fc;
}
@keyframes btn-22-top {
  0% {
    transform: translateY(100%);
  }
  100% {
    transform: translateY(-100%);
  }
}
@keyframes btn-22-left {
  0% {
    transform: translateX(100%);
  }
  100% {
    transform: translateX(-100%);
  }
}
@keyframes btn-22-bottom {
  0% {
    transform: translateY(-100%);
  }
  100% {
    transform: translateY(100%);
  }
}
@keyframes btn-22-right {
  0% {
    transform: translateX(-100%);
  }
  100% {
    transform: translateX(100%);
  }
}


.btn-23 {
  overflow: hidden;
  background-color: #333;
}
.btn-23:before {
  content: "";
  position: absolute;
  left: 50%;
  top: 0;
  height: 100%;
  width: 0%;
  background: red;
  border-radius: 23px;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-23:hover:before {
  width: 120%;
  left: -10%;
}
.btn-23:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-23:active {
  border-color: #00a7fc;
  color: #333;
  background-color: #00a7fc;
}
.btn-23:active:before {
  background-color: #00a7fc;
}
.btn-23:active {
  background-color: #00a7fc;
  border-color: #00a7fc;
  color: #333;
}
.btn-23:active:before {
  background-color: #00a7fc;
}


.btn-24 {
  background: #f1f1f1;
  overflow: hidden;
  background-color: red;
}
.btn-24:before {
  content: "";
  position: absolute;
  height: 100%;
  top: 0;
  width: 120%;
  left: -10%;
  background-color: #333;
  transition: all 0.5s ease-in-out;
  border-radius: 23px;
  z-index: -1;
}
.btn-24:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-24:hover:before {
  width: 0%;
  left: 50%;
}
.btn-24:active {
  background-color: #00a7fc;
  border-color: #00a7fc;
  color: #333;
}
.btn-24:active:before {
  background-color: #00a7fc;
}


.btn-25 {
  background: #333;
}
.btn-25:before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 50%;
  height: 0%;
  background-color: red;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-25:after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 0;
  width: 50%;
  height: 0%;
  background-color: red;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-25:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-25:hover:before,
.btn-25:hover:after {
  height: 100%;
}
.btn-25:active {
  color: #333;
  border-color: #00a7fc;
  background-color: #00a7fc;
}
.btn-25:active:before,
.btn-25:active:after {
  background-color: #00a7fc;
}


.btn-26 {
  background: #333;
}
.btn-26:before {
  content: "";
  position: absolute;
  right: 0;
  top: 0;
  width: 50%;
  height: 0%;
  background-color: red;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-26:after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 50%;
  height: 0%;
  background-color: red;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-26:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-26:hover:before,
.btn-26:hover:after {
  height: 100%;
}
.btn-26:active {
  color: #333;
  border-color: #00a7fc;
  background-color: #00a7fc;
}
.btn-26:active:before,
.btn-26:active:after {
  background-color: #00a7fc;
}


.btn-27 {
  background: #333;
}
.btn-27:before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 0%;
  height: 50%;
  background-color: red;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-27:after {
  content: "";
  position: absolute;
  bottom: 0%;
  right: 0%;
  width: 0%;
  height: 50%;
  background-color: red;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-27:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-27:hover:before,
.btn-27:hover:after {
  width: 100%;
}
.btn-27:active {
  color: #333;
  border-color: #00a7fc;
  background-color: #00a7fc;
}
.btn-27:active:before,
.btn-27:active:after {
  background-color: #00a7fc;
}


.btn-28 {
  background: #333;
}
.btn-28:before {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 50%;
  background-color: red;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-28:after {
  content: "";
  position: absolute;
  top: 0%;
  right: 0%;
  width: 0%;
  height: 50%;
  background-color: red;
  transition: all 0.5s ease-in-out;
  z-index: -1;
}
.btn-28:hover {
  color: #f1f1f1;
  border-color: red;
}
.btn-28:hover:before,
.btn-28:hover:after {
  width: 100%;
}
.btn-28:active {
  color: #333;
  border-color: #00a7fc;
  background-color: #00a7fc;
}
.btn-28:active:before,
.btn-28:active:after {
  background-color: #00a7fc;
}
JS

document.getElementById("btn1").onclick = function() { openModal(1) };
document.getElementById("btn2").onclick = function() { openModal(2) };
document.getElementById("btn3").onclick = function() { openModal(3) };
document.getElementById("btn4").onclick = function() { openModal(4) };
document.getElementById("btn5").onclick = function() { openModal(5) };
document.getElementById("btn6").onclick = function() { openModal(6) };
document.getElementById("btn7").onclick = function() { openModal(7) };
document.getElementById("btn8").onclick = function() { openModal(8) };
document.getElementById("btn9").onclick = function() { openModal(9) };
document.getElementById("btn10").onclick = function() { openModal(10) };
document.getElementById("btn11").onclick = function() { openModal(11) };
document.getElementById("btn12").onclick = function() { openModal(12) };
document.getElementById("btn13").onclick = function() { openModal(13) };
document.getElementById("btn14").onclick = function() { openModal(14) };
document.getElementById("btn15").onclick = function() { openModal(15) };
document.getElementById("btn16").onclick = function() { openModal(16) };
document.getElementById("btn17").onclick = function() { openModal(17) };
document.getElementById("btn18").onclick = function() { openModal(18) };
document.getElementById("btn19").onclick = function() { openModal(19) };
document.getElementById("btn20").onclick = function() { openModal(20) };
document.getElementById("btn21").onclick = function() { openModal(21) };
document.getElementById("btn22").onclick = function() { openModal(22) };
document.getElementById("btn23").onclick = function() { openModal(23) };
document.getElementById("btn24").onclick = function() { openModal(24) };
document.getElementById("btn25").onclick = function() { openModal(25) };
document.getElementById("btn26").onclick = function() { openModal(26) };
document.getElementById("btn27").onclick = function() { openModal(27) };
document.getElementById("btn28").onclick = function() { openModal(28) 
};