* {
  box-sizing: border-box;
}

body {
  font-family: 'Mulish', sans-serif;
  background-color: #f7f7f7;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 600px;
  margin: 50px auto;
  background-color: #fff;
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

h1 {
  color: #333;
  text-align: center;
  font-size: 36px;
  margin-bottom: 20px;
  font-weight: 700;
}

p {
  text-align: center;
  color: #666;
  font-size: 18px;
  margin-bottom: 30px;
}

.input-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  margin-bottom: 30px;
}

.input-group {
  flex-basis: 48%;
  margin-bottom: 20px;
}

label {
  display: block;
  font-weight: 700;
  margin-bottom: 10px;
  color: #333;
}

.flatpickr {
  width: 100%;
  padding: 12px;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 16px;
  transition: border-color 0.3s ease;
  font-family: 'Mulish', sans-serif;
  margin-bottom: 10px;
}

.flatpickr:focus {
  outline: none;
  border-color: #4CAF50;
}

.calculate-button {
  display: block;
  width: 100%;
  padding: 15px;
  background-color: #1a73e8;
  color: #ffffff;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-size: 18px;
  transition: background-color 0.3s ease;
  font-family: 'Mulish', sans-serif;
  font-weight: 700;
}

.calculate-button:hover {
  background-color: #1558d6;
}

#result {
  margin-top: 30px;
  text-align: center;
  font-size: 24px;
  font-weight: 700;
  color: #333;
  padding: 20px;
  background-color: #f2f2f2;
  border-radius: 6px;
}

.about {
  margin-top: 10px;
  text-align: left;
}

.about h2 {
  font-size: 28px;
  margin-bottom: 20px;
}

.about h3 {
  font-size: 22px;
  margin-top: 30px;
  margin-bottom: 15px;
}

.about p {
  text-align: left;
  margin-bottom: 15px;
}

.about ul {
  padding-left: 20px;
  margin-bottom: 20px;
}

.about li {
  margin-bottom: 10px;
}

footer {
  background-color: #f7f7f7;
  color: #333;
  padding: 15px 0;
  margin-top: 30px;
  font-size: 14px;
}

footer .container {
  text-align: center;
}

footer p {
  margin: 0;
}

footer a {
  color: #333;
  text-decoration: underline;
}

footer a:hover {
  text-decoration: none;
}

@media screen and (max-width: 600px) {
  .container {
    margin: 20px;
    padding: 20px;
  }

  .input-container {
    flex-direction: column;
  }

  .input-group {
    flex-basis: 100%;
  }
}

#result-container {
  margin-top: 30px;
}