:root {
    --primary-color: #6c5ce7;
    --secondary-color: #8e44ad;
    --background-color: #f8f9fa;
    --card-background: #ffffff;
    --text-color: #2d3436;
    --border-color: #dfe6e9;
    --success-color: #00b894;
    --warning-color: #fdcb6e;
    --danger-color: #d63031;
    --gradient-primary: linear-gradient(135deg, #6c5ce7 0%, #8e44ad 100%);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 40px 0;
    background: var(--gradient-primary);
    border-radius: 10px;
    color: white;
    box-shadow: 0 4px 15px rgba(108,92,231,0.3);
}

h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    font-weight: 600;
}


.tabs {
    display: flex;
    border-bottom: 2px solid var(--border-color);
    margin-bottom: 20px;
}

.tab {
    padding: 10px 20px;
    cursor: pointer;
    background-color: var(--card-background);
    border: 1px solid var(--border-color);
    border-bottom: none;
    border-radius: 5px 5px 0 0;
    margin-right: 5px;
    transition: background-color 0.3s;
}

.tab.active {
    background-color: var(--primary-color);
    color: white;
}

.tab:hover:not(.active) {
    background-color: #e9e9e9;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.card {
    background-color: var(--card-background);
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 20px;
    margin-bottom: 20px;
}

.form-group {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
}

input, select {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 16px;
}

select {
    cursor: pointer;
}

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

.btn:hover {
    background-color: var(--secondary-color);
}

.btn-danger {
    background-color: var(--danger-color);
}

.btn-danger:hover {
    background-color: #c0392b;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

th, td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background-color: #f2f2f2;
    font-weight: 600;
}

.action-cell {
    text-align: center;
}

.delete-btn {
    background-color: var(--danger-color);
    color: white;
    border: none;
    padding: 5px 10px;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.delete-btn:hover {
    background-color: #c0392b;
}

.result-container {
    background-color: var(--card-background);
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 20px;
    margin-top: 30px;
    text-align: center;
}

.result {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
    margin: 10px 0;
}

.semester-container {
    margin-bottom: 30px;
}

.semester-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}

.semester-title {
    font-size: 18px;
    font-weight: 600;
}

.semester-gpa {
    font-weight: bold;
    color: var(--primary-color);
}

.info-text {
    font-size: 14px;
    color: #666;
    margin-bottom: 15px;
}

.grade-info-table {
    width: 100%;
    margin-top: 20px;
    margin-bottom: 30px;
    border-collapse: collapse;
}

.grade-info-table th, .grade-info-table td {
    padding: 10px 12px;
    text-align: center;
    border: 1px solid var(--border-color);
}



.grade-info-table th {
    background-color: #f2f2f2;
}

/* Responsive adjustments */
@media screen and (max-width: 768px) {
    .tabs {
        flex-wrap: wrap;
    }
    
    .tab {
        flex-grow: 1;
        text-align: center;
        margin-bottom: 10px;
    }
    
    table {
        font-size: 14px;
    }
    
    th, td {
        padding: 8px;
    }
    
    .btn {
        padding: 8px 16px;
        font-size: 14px;
    }
}

@media screen and (max-width: 480px) {
    table {
        display: block;
        overflow-x: auto;
    }
    
    .semester-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .semester-gpa {
        margin-top: 5px;
    }
}