body {
  margin: 0;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: Arial;
  transition: 0.4s;
}

/* THEMES */
body.dark {
  background: linear-gradient(135deg, #0f172a, #1e3a8a);
  color: white;
}

body.light {
  background: linear-gradient(135deg, #e0f2fe, #ffffff);
  color: #111;
}

/* CARD */
.container {
  position: relative;
  padding: 30px;
  border-radius: 20px;
  width: 320px;
  text-align: center;
  transition: all 0.4s ease;
  backdrop-filter: blur(20px);
}

.container:hover {
  transform: translateY(-5px) scale(1.01);
}

body.dark .container {
  background: rgba(255, 255, 255, 0.1);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

body.light .container {
  background: rgba(255, 255, 255, 0.8);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
  border: 1px solid rgba(0, 0, 0, 0.1);
}

.container.expanded {
  width: 420px;
}

/* TOGGLE */
.toggle {
  position: absolute;
  top: 15px;
  right: 15px;
  cursor: pointer;
}

/* INPUTS */
.input-group {
  display: flex;
  gap: 10px;
  margin: 20px 0;
}

input,
select {
  padding: 12px;
  border-radius: 10px;
  border: none;
  flex: 1;
  outline: none;
  transition: 0.3s;
}

input:focus,
select:focus {
  box-shadow: 0 0 10px #38bdf8;
}

/* BUTTONS */
.btn-group {
  display: flex;
  gap: 10px;
  justify-content: center;
}

button {
  padding: 10px;
  border-radius: 10px;
  border: none;
  cursor: pointer;
  background: #38bdf8;
  color: white;
  transition: 0.3s;
}

button:hover {
  transform: scale(1.05);
}

/* RESULT */
.result-section {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: all 0.4s ease;
}

.result-section.show {
  max-height: 200px;
  opacity: 1;
}

.result-box {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.result-box p {
  padding: 10px;
  border-radius: 10px;
}

body.dark .result-box p {
  background: rgba(0, 0, 0, 0.4);
}

body.light .result-box p {
  background: rgba(255, 255, 255, 0.9);
}

/* HISTORY */
.history {
  margin-top: 20px;
  max-height: 120px;
  overflow-y: auto;
}

/* TOAST */
.toast {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: black;
  color: white;
  padding: 10px;
  border-radius: 10px;
  opacity: 0;
  transition: 0.3s;
}

.toast.show {
  opacity: 1;
}