/* CSS Variables */
:root {
    --primary: #2ECC71;
    --primary-dark: #27ae60;
    --secondary: #34495e;
    --accent: #3498db;
    --text-dark: #2c3e50;
    --text-light: #7f8c8d;
    --bg-light: #ecf0f1;
    --white: #ffffff;
    --success: #27ae60;
    --warning: #f39c12;
    --danger: #e74c3c;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
}

/* Navigation */
nav {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    cursor: pointer;
    text-decoration: none;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: 8px;
    margin-right: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 20px;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: color 0.3s;
    position: relative;
    cursor: pointer;
}

.nav-links a:hover {
    color: var(--primary);
}

/* Main Content Container */
.main-content {
    margin-top: 80px;
    min-height: calc(100vh - 80px);
}

/* Page Sections */
.page-section {
    display: none;
    animation: fadeIn 0.5s ease;
}

.page-section.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Hero Section */
.hero {
    padding: 4rem 2rem;
    background: linear-gradient(135deg, rgba(46, 204, 113, 0.1) 0%, rgba(52, 152, 219, 0.1) 100%);
    position: relative;
    overflow: hidden;
}

.hero-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-text h1 {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 1rem;
}

.hero-text p {
    font-size: 1.25rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
}

/* Buttons */
.btn {
    padding: 12px 28px;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(46, 204, 113, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(46, 204, 113, 0.4);
}

.btn-secondary {
    background: white;
    color: var(--primary);
    border: 2px solid var(--primary);
}

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

/* Progress Section */
.progress-section {
    padding: 4rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 3rem;
    font-size: 1.1rem;
}

.progress-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.progress-card {
    background: white;
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
}

.progress-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.12);
}

.progress-card.completed {
    border-top: 4px solid var(--success);
}

.progress-card.in-progress {
    border-top: 4px solid var(--warning);
}

.progress-card.pending {
    border-top: 4px solid var(--bg-light);
}

.worksheet-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 1rem;
}

.worksheet-number {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
}

.worksheet-status {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.status-completed {
    background: rgba(39, 174, 96, 0.1);
    color: var(--success);
}

.status-in-progress {
    background: rgba(243, 156, 18, 0.1);
    color: var(--warning);
}

.status-pending {
    background: var(--bg-light);
    color: var(--text-light);
}

.worksheet-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-dark);
    margin: 1rem 0 0.5rem;
}

.worksheet-description {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 1rem;
}

.worksheet-deadline {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-light);
    font-size: 0.9rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--bg-light);
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--bg-light);
    border-radius: 4px;
    overflow: hidden;
    margin-top: 1rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: 4px;
    transition: width 0.5s ease;
}

/* Worksheet Detail Pages */
.worksheet-detail {
    padding: 3rem 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.back-button {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--primary);
    text-decoration: none;
    margin-bottom: 2rem;
    font-weight: 600;
    transition: transform 0.3s;
}

.back-button:hover {
    transform: translateX(-5px);
}

.detail-header {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
}

.detail-content {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
}

.detail-content h3 {
    color: var(--primary);
    margin-top: 2rem;
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.detail-content h4 {
    color: var(--text-dark);
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

.detail-content p {
    color: var(--text-light);
    line-height: 1.8;
    margin-bottom: 1rem;
}

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

.detail-content li {
    color: var(--text-light);
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.highlight-box {
    background: linear-gradient(135deg, rgba(46, 204, 113, 0.1) 0%, rgba(52, 152, 219, 0.1) 100%);
    border-left: 4px solid var(--primary);
    padding: 1.5rem;
    margin: 1.5rem 0;
    border-radius: 8px;
}

.metric-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.metric-box {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: 12px;
    text-align: center;
}

.metric-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary);
    display: block;
}

.metric-label {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-top: 0.5rem;
}

/* Team Section */
.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.team-member {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
    transition: transform 0.3s ease;
}

.team-member:hover {
    transform: translateY(-5px);
}

.team-avatar {
    width: 120px;
    height: 120px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: 50%;
    margin: 0 auto 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    color: white;
    font-weight: 700;
}

.team-member h3 {
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.team-member .role {
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.team-member .education {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.team-member .bio {
    color: var(--text-light);
    line-height: 1.6;
}

/* Contact Form */
.contact-form {
    max-width: 600px;
    margin: 2rem auto;
    padding: 2rem;
    background: white;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--bg-light);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.submit-btn {
    width: 100%;
    padding: 15px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s ease;
}

.submit-btn:hover {
    background: var(--primary-dark);
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    z-index: 3000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: white;
    width: 95%;
    max-width: 1200px;
    height: 90vh;
    border-radius: 20px;
    overflow: hidden;
    position: relative;
}

.modal-close {
    position: absolute;
    top: 15px;
    right: 15px;
    background: var(--danger);
    color: white;
    border: none;
    width: 35px;
    height: 35px;
    border-radius: 50%;
    font-size: 18px;
    cursor: pointer;
    z-index: 10;
    transition: background 0.3s ease;
}

.modal-close:hover {
    background: #c0392b;
}

/* Footer */
footer {
    background: var(--secondary);
    color: white;
    padding: 3rem 2rem;
    text-align: center;
    margin-top: 4rem;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
}

table th {
    padding: 12px;
    text-align: left;
    font-weight: 600;
}

table td {
    padding: 10px 12px;
    border-bottom: 1px solid var(--bg-light);
}

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

table tbody tr:nth-child(even) {
    background: #f8f9fa;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-text h1 {
        font-size: 2rem;
    }
    
    .nav-links {
        display: none;
    }
    
    .cta-buttons {
        justify-content: center;
    }
    
    .metric-grid {
        grid-template-columns: 1fr;
    }
    
    .team-grid {
        grid-template-columns: 1fr;
    }
    
    .progress-grid {
        grid-template-columns: 1fr;
    }
    
    .worksheet-detail {
        padding: 2rem 1rem;
    }
    
    .nav-container {
        padding: 1rem;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 2rem 1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .progress-section {
        padding: 2rem 1rem;
    }
}