/* =========================================================
   Interakční animace — tlačítka, pole, chipy.
   Port z animations.css (design systém).
   ========================================================= */

.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 0;
  cursor: pointer;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 14px;
  text-decoration: none;
  letter-spacing: 0.01em;
  transition:
    transform 200ms var(--ease-out),
    background-color 200ms var(--ease-out),
    color 200ms var(--ease-out),
    box-shadow 250ms var(--ease-out),
    border-color 200ms ease;
  overflow: hidden;
  isolation: isolate;
  will-change: transform;
}
.btn:active { transform: translateY(1px) scale(0.985); }

.btn::before {
  content: "";
  position: absolute;
  top: 0; left: -120%;
  width: 60%; height: 100%;
  background: linear-gradient(120deg, transparent 0%, hsl(0 0% 100% / 0.18) 50%, transparent 100%);
  transform: skewX(-20deg);
  transition: left 700ms var(--ease-out);
  pointer-events: none;
  z-index: 0;
}
.btn:hover::before { left: 130%; }
.btn--dark::before { background: linear-gradient(120deg, transparent 0%, hsl(152 30% 25% / 0.12) 50%, transparent 100%); }

.btn .arrow,
.btn-link .arrow {
  display: inline-flex;
  transition: transform 250ms var(--ease-out);
}
.btn:hover .arrow,
.btn-link:hover .arrow { transform: translateX(4px); }

.btn--primary { background: var(--warm); color: var(--sage-dark); padding: 16px 32px; border-radius: 12px; }
.btn--primary:hover { background: var(--warm-dark); transform: translateY(-2px); box-shadow: 0 14px 28px -10px hsl(160 20% 5% / 0.45); }

.btn--ghost { background: transparent; color: var(--warm); padding: 14px 30px; border: 2px solid hsl(40 33% 96% / 0.4); border-radius: 12px; }
.btn--ghost:hover { border-color: var(--warm); transform: translateY(-2px); background: hsl(40 33% 96% / 0.06); }

.btn--sage { background: var(--sage); color: var(--warm); padding: 14px 24px; border-radius: 12px; }
.btn--sage:hover { background: var(--sage-dark); transform: translateY(-2px); box-shadow: 0 14px 28px -10px hsl(160 20% 5% / 0.4); }

.btn--pill { border-radius: 999px; padding: 16px 28px; }

.btn--submit { width: 100%; background: var(--warm); color: var(--sage-dark); padding: 18px 24px; border-radius: 999px; }
.btn--submit:hover { background: #fff; transform: translateY(-2px); box-shadow: 0 18px 36px -12px hsl(160 20% 5% / 0.55); }
.btn--submit:disabled { opacity: 0.7; cursor: default; transform: none; }

@keyframes btn-pop {
  0% { transform: scale(0.95); }
  60% { transform: scale(1.04); }
  100% { transform: scale(1); }
}
.btn--success {
  background: var(--sage) !important;
  color: var(--warm) !important;
  animation: btn-pop 380ms var(--ease-out);
}
.btn--success::before { display: none; }

.btn-link {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: inherit;
  text-decoration: none;
  font-family: var(--font-sans);
  font-weight: 500;
  cursor: pointer;
}
.btn-link::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -3px;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 320ms var(--ease-out);
}
.btn-link:hover::after { transform: scaleX(1); }

/* === Form fields === */
.field { position: relative; }
.field label.field-label {
  display: block;
  font-size: 12px;
  font-family: var(--font-sans);
  color: hsl(40 33% 96% / 0.6);
  margin-bottom: 6px;
  letter-spacing: 0.05em;
  transition: color 220ms ease;
}
.field:focus-within label.field-label { color: hsl(40 33% 96% / 0.95); }

.field-input,
.field-textarea {
  width: 100%;
  background: hsl(152 28% 38% / 0.18);
  border: 1px solid hsl(152 28% 38% / 0.3);
  border-radius: 12px;
  padding: 14px 16px;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--warm);
  box-sizing: border-box;
  outline: none;
  transition:
    background-color 220ms ease,
    border-color 220ms ease,
    box-shadow 280ms var(--ease-out);
}
.field-input::placeholder, .field-textarea::placeholder { color: hsl(40 33% 96% / 0.3); transition: color 220ms ease; }
.field-input:hover, .field-textarea:hover { border-color: hsl(152 20% 92% / 0.4); }
.field-input:focus, .field-textarea:focus {
  border-color: hsl(40 33% 96% / 0.6);
  background: hsl(152 28% 38% / 0.28);
  box-shadow: 0 0 0 4px hsl(40 33% 96% / 0.08);
}
.field-input:focus::placeholder, .field-textarea:focus::placeholder { color: hsl(40 33% 96% / 0.5); }
.field-input.has-error, .field-textarea.has-error { border-color: hsl(0 70% 60% / 0.8); }
.field-textarea { resize: none; line-height: 1.55; }

/* === Topic chips === */
.chip-group { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 16px;
  border-radius: 999px;
  border: 1px solid hsl(40 33% 96% / 0.25);
  font-family: var(--font-sans);
  font-size: 12px;
  color: hsl(40 33% 96% / 0.85);
  background: transparent;
  cursor: pointer;
  transition:
    transform 200ms var(--ease-out),
    background-color 220ms ease,
    color 220ms ease,
    border-color 220ms ease,
    box-shadow 240ms ease;
  user-select: none;
}
.chip:hover { transform: translateY(-1px); border-color: hsl(40 33% 96% / 0.55); color: var(--warm); }
.chip-input { position: absolute; opacity: 0; pointer-events: none; }
.chip-input:checked + .chip {
  background: var(--warm);
  color: var(--sage-dark);
  border-color: var(--warm);
  box-shadow: 0 6px 18px -6px hsl(160 20% 5% / 0.45);
  animation: chip-pulse 360ms var(--ease-out);
}
@keyframes chip-pulse {
  0% { transform: scale(0.92); }
  60% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

.lift { transition: transform 250ms var(--ease-out), box-shadow 280ms var(--ease-out); }
.lift:hover { transform: translateY(-3px); }

@media (prefers-reduced-motion: reduce) {
  .btn::before, .chip-input:checked + .chip { animation: none; }
  .btn, .chip, .lift, .field-input, .field-textarea, .btn-link::after { transition: none; }
}