/* CSS Variables */
:root {
    --burgundy-dark: #8B0000;
    --burgundy-primary: #A52A2A;
    --burgundy-light: #CD5C5C;
    --burgundy-lighter: #F5E6E6;
    --white: #FFFFFF;
    --gray-light: #F8F9FA;
    --gray-medium: #E9ECEF;
    --gray-dark: #495057;
    --text-primary: #212529;
    --text-secondary: #6C757D;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.16);
    --border-radius: 12px;
    --border-radius-sm: 8px;
}

/* Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: linear-gradient(135deg, var(--burgundy-lighter) 0%, var(--gray-light) 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
}

/* Header */
header {
    background: linear-gradient(135deg, var(--burgundy-dark) 0%, var(--burgundy-primary) 100%);
    color: var(--white);
    padding: 1.5rem 2rem;
    display: flex;
    align-items: center;
    gap: 1.5rem;
    box-shadow: var(--shadow-md);
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 700;
    font-size: 1.25rem;
}

.logo-circle {
    width: 32px;
    height: 32px;
    background: var(--white);
    border-radius: 50%;
    position: relative;
}

.logo-circle::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 12px;
    height: 12px;
    background: var(--burgundy-dark);
    border-radius: 50%;
}

header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

/* Main */
main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* Controls Section */
.controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1.5rem;
    margin-bottom: 2rem;
    background: var(--white);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
}

.semester-selector {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.semester-selector label {
    font-weight: 500;
    color: var(--text-secondary);
}

.semester-selector select {
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--gray-medium);
    border-radius: var(--border-radius-sm);
    background: var(--white);
    cursor: pointer;
    font-family: inherit;
    transition: all 0.2s ease;
}

.semester-selector select:hover {
    border-color: var(--burgundy-light);
}

.semester-selector select:focus {
    outline: none;
    border-color: var(--burgundy-primary);
    box-shadow: 0 0 0 3px rgba(165, 42, 42, 0.15);
}

/* Selector Group */
.selector-group {
    display: flex;
    gap: 2rem;
    align-items: center;
    flex-wrap: wrap;
}

.surname-selector {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.surname-selector label {
    font-weight: 500;
    color: var(--text-secondary);
}

.toggle-group {
    display: flex;
    border-radius: var(--border-radius-sm);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.toggle-btn {
    padding: 0.75rem 1.25rem;
    font-size: 0.875rem;
    font-weight: 600;
    font-family: inherit;
    border: 2px solid var(--gray-medium);
    background: var(--white);
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--text-secondary);
}

.toggle-btn:first-child {
    border-radius: var(--border-radius-sm) 0 0 var(--border-radius-sm);
    border-right: 1px solid var(--gray-medium);
}

.toggle-btn:last-child {
    border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
    border-left: 1px solid var(--gray-medium);
}

.toggle-btn:hover {
    background: var(--burgundy-lighter);
    border-color: var(--burgundy-light);
    color: var(--burgundy-dark);
}

.toggle-btn.active {
    background: linear-gradient(135deg, var(--burgundy-dark) 0%, var(--burgundy-primary) 100%);
    border-color: var(--burgundy-dark);
    color: var(--white);
}

/* GPA Summary Cards */
.gpa-summary {
    display: flex;
    gap: 1rem;
}

.gpa-card {
    background: linear-gradient(135deg, var(--burgundy-dark) 0%, var(--burgundy-primary) 100%);
    color: var(--white);
    padding: 1rem 2rem;
    border-radius: var(--border-radius-sm);
    text-align: center;
    box-shadow: var(--shadow-md);
    min-width: 150px;
}

.gpa-label {
    display: block;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    opacity: 0.9;
    margin-bottom: 0.25rem;
}

.gpa-value {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
}

/* Semester Cards */
.semester-card {
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    margin-bottom: 1.5rem;
    overflow: hidden;
    transition: box-shadow 0.2s ease;
}

.semester-card:hover {
    box-shadow: var(--shadow-md);
}

.semester-header {
    background: linear-gradient(135deg, var(--burgundy-primary) 0%, var(--burgundy-light) 100%);
    color: var(--white);
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.semester-header h2 {
    font-size: 1.125rem;
    font-weight: 600;
}

.semester-stats {
    display: flex;
    gap: 1.5rem;
    font-size: 0.875rem;
}

.semester-stats span {
    background: rgba(255, 255, 255, 0.2);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
}

/* Course Table */
.course-table {
    width: 100%;
    border-collapse: collapse;
}

.course-table th,
.course-table td {
    padding: 0.875rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--gray-medium);
}

.course-table th {
    background: var(--gray-light);
    font-weight: 600;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
}

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

.course-table tr:hover td {
    background: var(--burgundy-lighter);
}

.course-code {
    font-weight: 600;
    color: var(--burgundy-dark);
    font-family: 'Menlo', 'Monaco', monospace;
    font-size: 0.875rem;
}

.course-name {
    color: var(--text-primary);
}

.course-credits {
    text-align: center;
    font-weight: 500;
}

/* Grade Select */
.grade-select {
    padding: 0.5rem 0.75rem;
    font-size: 0.875rem;
    border: 2px solid var(--gray-medium);
    border-radius: var(--border-radius-sm);
    background: var(--white);
    cursor: pointer;
    font-family: inherit;
    font-weight: 500;
    min-width: 80px;
    transition: all 0.2s ease;
}

.grade-select:hover {
    border-color: var(--burgundy-light);
}

.grade-select:focus {
    outline: none;
    border-color: var(--burgundy-primary);
    box-shadow: 0 0 0 3px rgba(165, 42, 42, 0.15);
}

.grade-select.grade-aa {
    background: #D4EDDA;
    border-color: #28A745;
}

.grade-select.grade-ba {
    background: #D4EDDA;
    border-color: #5CB85C;
}

.grade-select.grade-bb {
    background: #CCE5FF;
    border-color: #0D6EFD;
}

.grade-select.grade-cb {
    background: #CCE5FF;
    border-color: #5BC0DE;
}

.grade-select.grade-cc {
    background: #FFF3CD;
    border-color: #FFC107;
}

.grade-select.grade-dc {
    background: #FFE5D0;
    border-color: #FD7E14;
}

.grade-select.grade-dd {
    background: #F8D7DA;
    border-color: #DC3545;
}

.grade-select.grade-fd {
    background: #F8D7DA;
    border-color: #C82333;
}

.grade-select.grade-ff {
    background: #E9ECEF;
    border-color: #6C757D;
}

.grade-select.grade-na {
    background: var(--white);
    border-color: var(--gray-medium);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.grading-info {
    margin-top: 0.5rem;
    font-size: 0.75rem;
    color: var(--burgundy-primary);
    font-weight: 500;
}

/* Responsive */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        text-align: center;
    }

    header h1 {
        font-size: 1.25rem;
    }

    .controls {
        flex-direction: column;
        align-items: stretch;
    }

    .semester-selector {
        flex-direction: column;
        align-items: stretch;
    }

    .gpa-summary {
        justify-content: center;
    }

    .semester-stats {
        flex-direction: column;
        gap: 0.5rem;
    }

    .course-table {
        font-size: 0.875rem;
    }

    .course-table th:nth-child(3),
    .course-table td:nth-child(3) {
        display: none;
    }
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.semester-card {
    animation: fadeIn 0.3s ease forwards;
}

.semester-card:nth-child(1) {
    animation-delay: 0.05s;
}

.semester-card:nth-child(2) {
    animation-delay: 0.1s;
}

.semester-card:nth-child(3) {
    animation-delay: 0.15s;
}

.semester-card:nth-child(4) {
    animation-delay: 0.2s;
}

.semester-card:nth-child(5) {
    animation-delay: 0.25s;
}

.semester-card:nth-child(6) {
    animation-delay: 0.3s;
}

.semester-card:nth-child(7) {
    animation-delay: 0.35s;
}

.semester-card:nth-child(8) {
    animation-delay: 0.4s;
}