html {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(to right, #434343, #000000);
}

.copyleft {
  display: inline-block;
  transform: scaleX(-1);
}

body {
  display: flex;
  max-width: 60vw;
  min-width: 600px;
  margin: 0 auto;
  flex-direction: column;
  align-items: center;
  margin-top: 50px;
  border: 4px solid black;
  background-color: #121212;
  color: rgba(255, 255, 255, 0.87);
}

p {
  margin: 16px 10px;
}

hr {
  margin: 0 auto;
}

#navbar {
  background-color: #2c2c2c;
  padding: 20px;
  box-sizing: border-box;
  width: 100%;
  border-bottom: 2px solid #555;
}

header {
  width: 100%;
  text-align: center;
  box-sizing: border-box;
}

ul {
  display: flex;
  flex-direction: row;
  list-style: none;
  gap: 20px;
  padding: 0;
  margin: 0;
  justify-content: space-evenly;
}

main {
  text-align: center;
}

a {
  color: #38bdf8;
  text-decoration: none;
  transition: color 0.2s ease;
}

a:visited {
  color: #c084fc;
}

a:hover {
  color: #7dd3fc;
  text-decoration: underline;
}

a:visited:hover {
  color: #e9d5ff;
}
a:active {
  color: #0284c7;
}

a:visited:active {
  color: #a855f7;
}

footer {
  text-align: center;
  margin: 0 auto;
}

#homework-table > table {
  border-collapse: collapse;
  width: 50%;
  margin: 0 auto;
  margin-bottom: 20px;
}

th {
  border: 1px solid #ddd;
  padding: 8px;
}

footer {
  margin: 10px;
}

#result-text {
  margin-top: 0;
}

#select-btn {
  width: 100px;
  height: 40px;
  font-size: 1.2em;
  font-weight: 600;
  border: 0;
  margin-top: 10px;
  margin-bottom: 16px;
}

form {
  width: 80%;
  margin: 20px auto;
  text-align: left;
}
.form-group {
  margin-bottom: 20px;
}
label {
  display: block;
  margin-bottom: 8px;
  font-weight: bold;
}
input[type="text"],
input[type="email"],
select {
  width: 100%;
  padding: 10px;
  box-sizing: border-box;
  background-color: #2c2c2c;
  color: white;
  border: 1px solid #555;
  border-radius: 4px;
}
.checkbox-group {
  display: flex;
  align-items: center;
  gap: 10px;
}
.checkbox-group label {
  margin-bottom: 0;
  font-weight: normal;
}
.error-message {
  color: #ff6b6b;
  font-size: 0.9em;
  display: none;
  margin-top: 5px;
}
#submit-btn {
  width: 150px;
  height: 40px;
  font-size: 1.1em;
  font-weight: 600;
  border: 0;
  margin-top: 10px;
  background-color: #38bdf8;
  color: #121212;
  cursor: pointer;
  border-radius: 4px;
}
#submit-btn:hover {
  background-color: #7dd3fc;
}
#success-message {
  color: #4ade80;
  font-weight: bold;
  display: none;
  text-align: center;
  margin-top: 20px;
}