* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #1a1a2e, #16213e);
  color: #fff;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
.center { text-align: center; padding: 40px 20px; }
h1 { font-size: 2.2rem; margin-bottom: 8px; }
p { color: #9ca3af; margin-bottom: 50px; }
.btns { display: flex; gap: 30px; flex-wrap: wrap; justify-content: center; }

.btn {
  position: relative;
  background: transparent;
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  padding: 15px 40px;
  border: none;
  cursor: pointer;
  letter-spacing: 1px;
}
.btn::before,
.btn::after {
  content: "";
  position: absolute;
  width: 10px;
  height: 10px;
  transition: all 0.4s ease;
}
/* top-left pair */
.btn::before {
  top: 0; left: 0;
  border-top: 2px solid currentColor;
  border-left: 2px solid currentColor;
}
.btn::after {
  top: 0; left: 0;
  border-top: 4px solid currentColor;
  border-left: 4px solid currentColor;
  width: 0; height: 0;
}
/* slide effect via span layers */
.btn span, .btn b {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.btn b::before,
.btn b::after {
  content: "";
  position: absolute;
  width: 10px;
  height: 10px;
  transition: all 0.4s ease;
}

/* Colors */
.btn.purple { color: #a78bfa; }
.btn.cyan { color: #22d3ee; }
.btn.green { color: #4ade80; }
.btn.coral { color: #fb7185; }

/* Using 4 corner brackets approach with pseudo elements on the button itself */
.btn.purple::before,
.btn.purple::after,
.btn.cyan::before,
.btn.cyan::after,
.btn.green::before,
.btn.green::after,
.btn.coral::before,
.btn.coral::after {
  position: absolute;
  width: 14px;
  height: 14px;
  transition: all 0.4s ease;
  opacity: 0;
}

.btn:hover::before {
  top: -2px; left: -2px;
  border-top: 2px solid currentColor;
  border-left: 2px solid currentColor;
  opacity: 1;
}
.btn:hover::after {
  bottom: -2px; right: -2px;
  border-bottom: 2px solid currentColor;
  border-right: 2px solid currentColor;
  opacity: 1;
}

/* Move the corners apart on hover to create the "double line" feel */
.btn::before { top: 0; left: 0; border-top: 2px solid currentColor; border-left: 2px solid currentColor; width: 12px; height: 12px; opacity: 0.6; transition: all 0.4s ease; }
.btn:hover::before { top: -8px; left: -8px; width: 18px; height: 18px; opacity: 1; }
.btn::after { bottom: 0; right: 0; border-bottom: 2px solid currentColor; border-right: 2px solid currentColor; width: 12px; height: 12px; opacity: 0.6; transition: all 0.4s ease; }
.btn:hover::after { bottom: -8px; right: -8px; width: 18px; height: 18px; opacity: 1; }

/* Inner second line */
.btn i {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.btn i::before {
  content: "";
  position: absolute;
  top: 4px; left: 4px; right: 4px; bottom: 4px;
  border: 1px solid currentColor;
  opacity: 0;
  transform: scale(0.6);
  transition: all 0.35s ease;
}
.btn:hover i::before { opacity: 0.8; transform: scale(1); }
@media (max-width: 600px) {
  h1 { font-size: 1.8rem; }
  .btns { gap: 20px; }
}