/* Custom CSS Variables */
:root {
    /* Colors */
    --primary-green: #11998e;
    --primary-green-light: #38ef7d;
    --primary-purple: #6a11cb;
    --primary-purple-light: #2575fc;
    --primary-orange: #f46b45;
    --primary-orange-light: #eea849;
    --text-dark: #2c3e50;
    --text-light: #666;
    --white: #ffffff;
    --gray-100: #f8f9fa;
    --gray-200: #e9ecef;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 2.5rem;
    
    /* Shadows */
    --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 8px 15px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 12px 20px rgba(0, 0, 0, 0.15);
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 15px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

body {
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.5;
    color: var(--text-dark);
    background-color: var(--gray-100);
}

/* Custom Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Custom Grid System */
.grid {
    display: grid;
    gap: var(--spacing-md);
}

.grid-auto-fit {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

/* Custom Utilities */
.text-center { text-align: center; }
.py-5 { padding-top: var(--spacing-xl); padding-bottom: var(--spacing-xl); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-lg); }

/* Section Title */
.section-title {
    text-align: center;
    color: var(--text-dark);
    font-size: 2.2rem;
    margin-bottom: var(--spacing-xl);
    font-weight: 600;
    position: relative;
    padding-bottom: var(--spacing-sm);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 120px;
    height: 4px;
    background: linear-gradient(135deg, var(--primary-purple) 0%, var(--primary-purple-light) 100%);
    border-radius: 2px;
}

/* Grade Container */
.grade-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
    padding: var(--spacing-sm);
}

/* Grade Button */
.grade-button {
    background: var(--white);
    border: none;
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    position: relative;
    overflow: hidden;
}

.grade-button:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.grade-button .grade-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-xs);
    transition: transform var(--transition-normal);
}

.grade-button:hover .grade-icon {
    transform: scale(1.1);
}

.grade-button h3 {
    color: var(--text-dark);
    font-size: 1.5rem;
    margin: 0;
    font-weight: 600;
}

.grade-button p {
    color: var(--text-light);
    font-size: 1rem;
    margin: 0;
}

.grade-description {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    padding: var(--spacing-sm);
    opacity: 0;
    transform: translateY(100%);
    transition: all var(--transition-normal);
    border-top: 1px solid var(--gray-200);
}

.grade-button:hover .grade-description {
    opacity: 1;
    transform: translateY(0);
}

/* Grade-specific styles */
.grade-button:nth-child(1) {
    border-top: 5px solid var(--primary-green);
    background: linear-gradient(to bottom, rgba(17, 153, 142, 0.05), var(--white));
}

.grade-button:nth-child(2) {
    border-top: 5px solid var(--primary-purple);
    background: linear-gradient(to bottom, rgba(106, 17, 203, 0.05), var(--white));
}

.grade-button:nth-child(3) {
    border-top: 5px solid var(--primary-orange);
    background: linear-gradient(to bottom, rgba(244, 107, 69, 0.05), var(--white));
}

/* Term Grid */
.term-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
}

/* Term Card */
.term-card {
    background: var(--white);
    border: none;
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    text-align: center;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
    cursor: pointer;
    width: 100%;
    text-decoration: none;
    color: inherit;
}

.term-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.term-card .card-icon {
    font-size: 2.2rem;
    margin-bottom: var(--spacing-sm);
}

.term-card h6 {
    color: var(--text-dark);
    font-size: 1.2rem;
    margin: 0.8rem 0 0.4rem;
    font-weight: 600;
}

.term-card p {
    color: var(--text-light);
    font-size: 0.9rem;
    margin: 0;
}

/* Grade-specific card styles */
.grade1-card {
    border-top: 4px solid var(--primary-green);
    background: linear-gradient(to bottom, rgba(17, 153, 142, 0.05), var(--white));
}

.grade2-card {
    border-top: 4px solid var(--primary-purple);
    background: linear-gradient(to bottom, rgba(106, 17, 203, 0.05), var(--white));
}

.grade3-card {
    border-top: 4px solid var(--primary-orange);
    background: linear-gradient(to bottom, rgba(244, 107, 69, 0.05), var(--white));
}

/* Responsive Design */
@media (max-width: 768px) {
    .grade-container {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .grade-button {
        padding: var(--spacing-md);
    }

    .grade-button .grade-icon {
        font-size: 2rem;
    }

    .grade-button h3 {
        font-size: 1.3rem;
    }

    .term-grid {
        grid-template-columns: 1fr;
    }
    
    .term-card {
        padding: var(--spacing-sm);
    }
    
    .section-title {
        font-size: 1.8rem;
    }

    .grade-description {
        position: relative;
        opacity: 1;
        transform: none;
        background: none;
        padding: var(--spacing-xs) 0 0;
        border-top: none;
    }
}