:root {
    --primary: #4361ee;
    --secondary: #3f37c9;
    --accent: #4cc9f0;
    --light: #f8f9fa;
    --dark: #212529;
    --success: #4ade80;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    
    color: var(--dark);
    background-color: var(--light);
    margin: 0;
    padding: 0;
    overflow-x: hidden;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    background: linear-gradient(to right, var(--primary), var(--secondary));
    color: white;
    padding: 20px 0;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

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

.logo {
    font-size: 24px;
    font-weight: bold;
    color: white;
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 20px;
}

.nav-links a {
    color: white;
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 4px;
    transition: background-color 0.3s, transform 0.2s;
}

.nav-links a:hover {
    background-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.nav-links a.active {
    background-color: rgba(255, 255, 255, 0.3);
    font-weight: bold;
}

.hero {
    padding: 60px 0;
    text-align: center;
    animation: fadeIn 1s ease-in-out;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: var(--primary);
}

.hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 30px;
    color: var(--dark);
}

.course-inputs {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    animation: slideUp 0.8s ease-out;
}

.input-group {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 20px;
}

.input-item {
    flex: 1;
    min-width: 200px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}

input, select {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 16px;
}

.btn {
    display: inline-block;
    background-color: var(--primary);
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
    margin-right: 10px;
    margin-bottom: 10px;
}

.btn:hover {
    background-color: var(--secondary);
    transform: translateY(-2px);
}

.table-container {
    margin-bottom: 30px;
    overflow-x: auto;
    animation: slideUp 1s ease-out;
}

table {
    width: 100%;
    border-collapse: collapse;
    background-color: white;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    border-radius: 8px;
    overflow: hidden;
}

th, td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

th {
    background-color: var(--primary);
    color: white;
}

tr:nth-child(even) {
    background-color: #f9f9f9;
}

tr:hover {
    background-color: #f1f1f1;
}

tfoot tr {
    background-color: #e9ecef;
    font-weight: bold;
}

.edit-btn, .delete-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    margin: 0 5px;
}

.edit-btn {
    color: var(--primary);
}

.delete-btn {
    color: #e63946;
}

.calculation-display {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    animation: slideUp 1.1s ease-out;
}

.calculation-box {
    background-color: #f8f9fa;
    padding: 15px;
    border-radius: 4px;
    border-left: 4px solid var(--primary);
    font-size: 1.1rem;
}

.calculation-box p {
    margin: 10px 0;
}

.calculation-box span {
    font-weight: bold;
    color: var(--primary);
}

.results {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    text-align: center;
    animation: slideUp 1.2s ease-out;
}

.gpa-display {
    font-size: 3rem;
    font-weight: bold;
    color: var(--primary);
    margin: 20px 0;
    animation: pulseScale 1.5s infinite alternate;
}

.download-btn {
    background-color: var(--success);
    color: white;
    padding: 12px 24px;
    border: none;
    border-radius: 4px;
    font-size: 18px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
    margin-top: 20px;
}

.download-btn:hover {
    background-color: #3cb371;
    transform: translateY(-2px);
}

.motivation-box {
    background: linear-gradient(to right, var(--primary), var(--accent));
    border-radius: 8px;
    padding: 20px;
    color: white;
    margin-bottom: 30px;
    text-align: center;
    animation: fadeIn 1.5s ease-in-out;
}

.motivation-box h3 {
    margin-top: 0;
}

.how-to-calculate {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.how-to-calculate h2 {
    color: var(--primary);
    margin-top: 0;
}

.grade-conversion {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 20px 0;
}

.grade-item {
    background-color: #f8f9fa;
    border-radius: 4px;
    padding: 8px 16px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

footer {
    background-color: var(--dark);
    color: white;
    text-align: center;
    padding: 20px 0;
    margin-top: 30px;
}

/* Tooltip for motivation */
.tooltip {
    position: relative;
    display: inline-block;
    cursor: pointer;
}

.tooltip .tooltiptext {
    visibility: hidden;
    width: 300px;
    background-color: var(--dark);
    color: white;
    text-align: center;
    border-radius: 6px;
    padding: 10px;
    position: absolute;
    z-index: 1;
    bottom: 125%;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    transition: opacity 0.3s;
}

.tooltip:hover .tooltiptext {
    visibility: visible;
    opacity: 1;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { transform: translateY(50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

@keyframes pulseScale {
    from { transform: scale(1); }
    to { transform: scale(1.05); }
}

/* Responsive Design */
@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 15px;
    }
    
    .nav-links {
        width: 100%;
        justify-content: center;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .input-item {
        min-width: 100%;
    }
}