* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
    display: flex;
}

header {
    position: fixed;
    left: 0;
    top: 0;
    width: 250px;
    height: 100vh;
    background: linear-gradient(180deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 2rem 0;
    box-shadow: 4px 0 12px rgba(0, 0, 0, 0.15);
    display: flex;
    flex-direction: column;
}

h1 {
    padding: 0 2rem;
    margin-bottom: 3rem;
    font-size: 1.8rem;
    border-bottom: 2px solid rgba(255, 255, 255, 0.2);
    padding-bottom: 1.5rem;
}

nav {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    flex: 1;
}

nav a {
    color: white;
    text-decoration: none;
    padding: 1rem 2rem;
    background-color: transparent;
    border-left: 4px solid transparent;
    transition: all 0.3s ease;
    font-weight: 500;
    font-size: 1rem;
}

nav a:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-left-color: #fff;
    padding-left: 2.5rem;
}

nav a.active {
    background-color: rgba(255, 255, 255, 0.2);
    border-left-color: #fff;
}

main {
    margin-left: 250px;
    flex: 1;
    max-width: calc(100% - 250px);
    padding: 2rem;
}

main > div {
    background: white;
    border-radius: 12px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
    padding: 2rem;
}

h2 {
    color: #667eea;
    margin-bottom: 1.5rem;
    font-size: 2rem;
}

h3 {
    color: #667eea;
    margin-top: 1.5rem;
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

p {
    line-height: 1.6;
    margin-bottom: 1rem;
    color: #555;
}

ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

li {
    line-height: 1.8;
    margin-bottom: 0.5rem;
    color: #555;
}

form {
    background: #f8f9fa;
    padding: 2rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    border: 1px solid #e9ecef;
}

label {
    display: block;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #333;
}

input {
    width: 100%;
    padding: 0.75rem;
    margin-top: 0.5rem;
    border: 2px solid #e9ecef;
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

input:focus {
    outline: none;
    border-color: #667eea;
    background-color: #f0f4ff;
}

input[type="checkbox"] {
    width: auto;
    margin-right: 0.5rem;
}

button {
    padding: 0.75rem 2rem;
    margin-top: 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px rgba(102, 126, 234, 0.3);
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(102, 126, 234, 0.4);
}

button:active {
    transform: translateY(0);
}

#results {
    background: #f0f4ff;
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid #667eea;
    margin-top: 2rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 2rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    border-radius: 8px;
    overflow: hidden;
}

th {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1rem;
    text-align: left;
    font-weight: 600;
}

td {
    padding: 1rem;
    border-bottom: 1px solid #e9ecef;
}

tr:hover {
    background-color: #f8f9fa;
}

tr:last-child td {
    border-bottom: none;
}