:root {
  color-scheme: light;
  --barva-pozadi: #c0e0f0;
  --barva-text: #0f172a;
  --barva-spravne: #22c55e;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  background: var(--barva-pozadi);
  color: var(--barva-text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
}

[hidden] {
  display: none !important;
}

main {
  width: 100%;
  max-width: 1100px;
  padding: 1rem;
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: flex-start;
}

#menu-screen,
#game-screen {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.menu-wrapper,
.mapa-wrapper {
  position: relative;
  width: 100%;
  margin: 0 auto;
  line-height: 0;
}

#menu-obrazek {
  display: block;
  width: 100%;
  height: auto;
  pointer-events: none;
  user-select: none;
}

#menu-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

#menu-kruh {
  position: absolute;
  top: 12%;
  left: 12%;
  width: clamp(144px, 33%, 390px);
  height: auto;
  transform: translate(-50%, -50%);
  pointer-events: none;
  user-select: none;
  z-index: 3;
  animation:
    menu-kruh-x 23s ease-in-out infinite alternate,
    menu-kruh-y 17s ease-in-out infinite alternate;
}

@keyframes menu-kruh-x {
  from { left: 14%; }
  to   { left: 82%; }
}

@keyframes menu-kruh-y {
  from { top: 10%; }
  to   { top: 80%; }
}

.menu-tlacitko {
  fill: rgba(255, 255, 255, 0);
  cursor: pointer;
  transform-box: fill-box;
  transform-origin: center;
  transition: fill 0.2s ease, transform 0.2s ease;
}

.menu-tlacitko:hover {
  fill: rgba(255, 255, 255, 0.25);
  transform: scale(1.04);
}

#mapa-obrazek {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 8px;
  pointer-events: none;
  user-select: none;
}

#mapa-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

#nazev-reky {
  position: absolute;
  top: 4%;
  left: 50%;
  transform: translateX(-50%);
  width: 90%;
  margin: 0;
  text-align: center;
  pointer-events: none;
  color: #ffffff;
  font-size: clamp(1.5rem, 5vw, 2.75rem);
  font-weight: 800;
  letter-spacing: 0.02em;
  -webkit-text-stroke: 1.5px rgba(15, 23, 42, 0.85);
  text-shadow:
    0 0 6px rgba(15, 23, 42, 0.75),
    0 0 14px rgba(15, 23, 42, 0.55),
    0 2px 4px rgba(15, 23, 42, 0.6);
  z-index: 5;
}

.reka-viditelna {
  fill: transparent;
  pointer-events: none;
  transition: fill 0.15s ease, stroke 0.15s ease;
}

.reka-viditelna.spravne {
  fill: #2ecc40;
  stroke: #2ecc40;
  stroke-width: 2;
}

.reka-klik {
  fill: transparent;
  stroke: transparent;
  stroke-linejoin: round;
  stroke-linecap: round;
  pointer-events: stroke;
  cursor: pointer;
}