/* Global */
body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  background-color: #f7f7f9;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  font-size: 1rem;
}
/*  */

/* Light mode */
#container {
  text-align: center;
  align-items: center;
  background-color: #f9fafb;
  position: relative;
  margin: 0 auto;
  border: 1px solid #e5e7eb;
  padding: 50px;
  border-radius: 15px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1), 0 8px 20px rgba(0, 0, 0, 0.15);
  animation: fadeInUp 0.5s ease;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

#container > * {
  margin: 0.5rem 0;
}

#header {
  color: #2563eb;
  font-size: 2.5rem;
}

#result {
  font-size: 1.2rem;
  font-weight: bold;
}

#clear-input {
  padding: 0.4rem 0.8rem;
  border: none;
  border-radius: 8px;
  background: #f9fafb;
  cursor: pointer;
  font-size: 1rem;
  opacity: 0;
  visibility: hidden;
}

#clear-input.show {
  opacity: 1;
  visibility: visible;
}

#dark-mode {
  position: absolute;
  top: 1rem;
  right: 1rem;
  border-radius: 50%;
  border: none;
  background-color: #f9fafb;
  cursor: pointer;
}

#swap {
  background: linear-gradient(135deg, #2563eb, #1e40af);
  padding: 0.8rem 2rem;
  border-radius: 12px;
  border: none;
  margin-top: 1.5rem;
  color: white;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, background 0.3s ease;
  box-shadow: 0 6px 12px rgba(37, 99, 235, 0.3);
}

#swap:hover {
  transform: translateY(-2px);
  background: linear-gradient(135deg, #1e40af, #1e3a8a);
  box-shadow: 0 8px 16px rgba(30, 64, 175, 0.4);
}

#swap img {
  width: 20px;
  transition: transform 0.5s ease-in-out;
}

#swap:hover img {
  transform: rotate(180deg);
}

input {
  padding: 0.5rem 1rem;
  border-radius: 10px;
}

select {
  padding: 0.5rem 1rem;
  border-radius: 10px;
  border: 1px solid #ddd;
  background-color: white;
}

option {
  padding: 0.5rem 1rem;
  border-radius: 10px;
  border: 1px solid #ddd;
}

input:focus,
select:focus {
  outline: none;
  border: 1px solid #2563eb;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.3);
}

input:hover,
select:hover {
  border-color: #2563eb;
}

/*  */

/* Dark Mode */
.dark-mode-body {
  background-color: #111827;
  color: #f9fafb;
}

#container.dark-mode-container {
  background-color: #273449;
  border: 1px solid #374151;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.6);
}

.dark-mode-button {
  background: linear-gradient(135deg, #3b82f6, #1d4ed8);
  color: white;
}

.dark-mode-input {
  background-color: #374151;
  border: 1px solid #4b5563;
  color: #f9fafb;
}

.dark-mode-input:focus {
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.3);
}

.dark-mode-select {
  background-color: #374151;
  color: #f9fafb;
  border: 1px solid #4b5563;
}

#dark-mode.dark-mode-light {
  background-color: #273449;
}

#clear-input.dark-mode-clear {
  background-color: #273449;
}

@media (max-width: 620px) {
  #container {
    padding: 30px 20px;
    width: 90%;
  }

  #header {
    font-size: 2rem;
  }
}

@media (max-width: 480px) {
  #container {
    position: relative;
    padding: 20px 10px;
    width: 80%;
  }
  #header {
    font-size: 1.8rem;
  }
  #dark-mode {
    position: absolute !important;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    top: auto !important;
    right: auto !important;
  }
}