.base-btn-1 {
    position: relative;
    padding: 0.75rem 2.4rem;
    font-size: 0.8rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: #111;
    background: transparent;
    border: 1.5px solid #111;
    cursor: pointer;
    overflow: hidden;
    transition: color 0.35s ease;
  }
  .base-btn-1::before {
    content: '';
    position: absolute;
    inset: 0;
    background: #111;
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.35s cubic-bezier(0.77, 0, 0.175, 1);
    z-index: 0;
  }
  .btn-1 span { position: relative; z-index: 1; }
  .btn-1:hover { color: #f5f5f0; }
  .btn-1:hover::before { transform: scaleX(1); }

  /* ─── BUTTON 2 — Double border pulse ─── */
  .base-btn-2 {
    margin: 10px;
    position: relative;
    padding: 0.75rem 2.4rem;
    font-size: 0.9rem;
    font-style: italic;
    letter-spacing: 0.04em;
    color: #111;
    background: transparent;
    border: 1.5px solid #111;
    cursor: pointer;
    outline: none;
    box-shadow: 3px 3px 0 #111;
    transition: box-shadow 0.1s ease, transform 0.1s ease;
  }
  .base-btn-2:hover {
    transform: translate(-3px, -3px);
    box-shadow: 6px 6px 0 #111;
  }
  .base-btn-2:active {
    transform: translate(0, 0);
    box-shadow: 0 0 0 #111;
  }

  /* ─── BUTTON 3 — Corner tick crawl ─── */
  .base-btn-3 {
    position: relative;
    padding: 0.75rem 2.4rem;
    font-size: 0.8rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: #111;
    background: transparent;
    border: none;
    cursor: pointer;
  }
  .base-btn-3::before,
  .base-btn-3::after {
    content: '';
    position: absolute;
    width: 12px;
    height: 12px;
    transition: width 0.3s ease, height 0.3s ease;
  }
  .base-btn-3::before {
    top: 0; left: 0;
    border-top: 1.5px solid #111;
    border-left: 1.5px solid #111;
  }
  .base-btn-3::after {
    bottom: 0; right: 0;
    border-bottom: 1.5px solid #111;
    border-right: 1.5px solid #111;
  }
  /* Extra corners via inner spans */
  .base-btn-3 .c-tr, .base-btn-3 .c-bl {
    position: absolute;
    width: 12px;
    height: 12px;
    transition: width 0.3s ease, height 0.3s ease;
  }
  .base-btn-3 .c-tr { top: 0; right: 0; border-top: 1.5px solid #111; border-right: 1.5px solid #111; }
  .base-btn-3 .c-bl { bottom: 0; left: 0; border-bottom: 1.5px solid #111; border-left: 1.5px solid #111; }
  .base-btn-3:hover::before,
  .base-btn-3:hover::after,
  .base-btn-3:hover .c-tr,
  .base-btn-3:hover .c-bl {
    width: 100%; height: 100%;
  }

  /* ─── BUTTON 4 — Glitch flicker ─── */
  .base-btn-4 {
    position: relative;
    padding: 0.75rem 2.4rem;
    font-size: 0.8rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: #111;
    background: #111;
    color: #f5f5f0;
    border: 1.5px solid #111;
    cursor: pointer;
  }
  .base-btn-4::before {
    content: attr(data-label);
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f5f5f0;
    color: #111;
    clip-path: inset(100% 0 0 0);
    transition: none;
  }
  .base-btn-4:hover::before {
    animation: glitch-reveal 0.4s steps(1) forwards;
  }
  @keyframes glitch-reveal {
    0%   { clip-path: inset(80% 0 0 0); }
    20%  { clip-path: inset(20% 0 60% 0); }
    40%  { clip-path: inset(55% 0 10% 0); }
    60%  { clip-path: inset(10% 0 45% 0); }
    80%  { clip-path: inset(40% 0 20% 0); }
    100% { clip-path: inset(0% 0 0 0); }
  }

  /* ─── BUTTON 5 — Underline scan ─── */
  .base-btn-5 {
    position: relative;
    padding: 0.75rem 2.4rem;
    font-size: 1rem;
    letter-spacing: 0.06em;
    color: #111;
    background: transparent;
    border: 1.5px solid #111;
    cursor: pointer;
    overflow: hidden;
  }
  .base-btn-5::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 100%;
    height: 1.5px;
    background: #111;
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s cubic-bezier(0.77, 0, 0.175, 1);
  }
  .base-btn-5 .scan {
    position: absolute;
    top: 0; left: -100%;
    width: 100%; height: 100%;
    background: repeating-linear-gradient(
      0deg,
      transparent,
      transparent 3px,
      rgba(0,0,0,0.04) 3px,
      rgba(0,0,0,0.04) 4px
    );
    transition: left 0.4s ease;
  }
  .base-btn-5:hover .scan { left: 0; }
  .base-btn-5:hover::after { transform: scaleX(1); }