:root {
  --color-dark: #2a2a2a;
  --color-light: #dadada;
}

body {
  margin: 0;
  font-family: "Noto Sans", sans-serif;
  background-color: var(--color-dark);
  color: var(--color-light);
}

a {
  text-decoration: none;
}

.link {
  text-decoration: none;
  color: var(--color-light);
  font-weight: 500;
}
.link:hover {
  text-decoration: underline;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem;
}

.main {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.heading {
  font-size: 3em;
  font-family: "Carter One", system-ui;
  text-shadow: 2px 2px 15px rgba(var(--color-light), 0.9);
}

.btn {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  font-family: "Noto Sans", sans-serif;
  font-size: 1em;
  font-weight: 500;
  color: var(--color-light);
  background-color: transparent;
  border: 1px solid var(--color-light);
  border-radius: 50rem;
  padding: 0.4rem 0.8rem;
  cursor: pointer;
  transition: 0.1s background-color linear, 0.1s color linear;
}
.btn:hover {
  background-color: var(--color-light);
  color: var(--color-dark);
}

.click-btn {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  font-family: "Noto Sans", sans-serif;
  font-size: 1.4em;
  font-weight: 500;
  color: var(--color-dark);
  border: 2px solid var(--color-dark);
  background-color: var(--color-light);
  border-radius: 50rem;
  padding: 0.4rem 0.8rem;
  cursor: pointer;
  transition: 0.1s transform linear;
  margin-bottom: 2rem;
}
.click-btn:hover {
  transform: scale(1.05);
}
.click-btn:active {
  transform: scale(0.95);
}

.mood-counter {
  font-weight: 500;
  font-size: 1.6em;
  margin-bottom: 1rem;
}

#upgrades {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin-bottom: 1rem;
}

.upgrade {
  padding: 0;
  width: 3.6rem;
  height: 3.6rem;
  border: none;
  border-radius: 8px;
  overflow: hidden;
  cursor: pointer;
  transition: 0.1s transform linear;
}
.upgrade > img {
  width: 100%;
  height: 100%;
}
.upgrade:hover {
  transform: scale(1.08);
}
.upgrade:active {
  transform: scale(0.95);
}

#upgrade-info {
  visibility: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  background-color: var(--color-light);
  color: var(--color-dark);
  padding: 1rem;
  border-radius: 8px;
}