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

:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --white: #ffffff;
    --border-radius: 4px;
    --transition: all 0.3s ease;
    --shadow: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-lg: 0 4px 8px rgba(0,0,0,0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-color);
}

/* Navigation */
.navbar {
    background-color: var(--dark-color);
    color: var(--white);
    padding: 0;
    box-shadow: var(--shadow-lg);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--white);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-item {
    position: relative;
}

.nav-link {
    color: var(--white);
    text-decoration: none;
    padding: 0.5rem 1rem;
    display: block;
    transition: var(--transition);
}

.nav-link:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
}

.dropdown {
    position: relative;
}

.dropdown-content {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background-color: var(--white);
    min-width: 200px;
    box-shadow: var(--shadow-lg);
    border-radius: var(--border-radius);
    margin-top: 0.5rem;
    z-index: 1001;
}

.dropdown:hover .dropdown-content {
    display: block;
}

.dropdown-content a {
    color: var(--dark-color);
    padding: 0.75rem 1rem;
    text-decoration: none;
    display: block;
    transition: var(--transition);
}

.dropdown-content a:hover {
    background-color: var(--light-color);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    flex-direction: column;
    gap: 4px;
}

.nav-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--white);
    transition: var(--transition);
}

.auth-section {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.user-email {
    color: var(--white);
    margin-right: 1rem;
}

/* Main Content */
.main-content {
    min-height: calc(100vh - 80px);
    padding: 2rem 1rem;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

.page {
    display: none;
    animation: fadeIn 0.3s ease;
}

.page.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--dark-color);
}

.lead {
    font-size: 1.25rem;
    color: var(--secondary-color);
    margin-bottom: 2rem;
}

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

.card {
    background-color: var(--white);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

/* Buttons */
.btn {
    padding: 0.5rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    transition: var(--transition);
    text-decoration: none;
    display: inline-block;
}

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

.btn-primary:hover {
    background-color: #0056b3;
}

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

.btn-secondary:hover {
    background-color: #545b62;
}

.btn-block {
    display: block;
    width: 100%;
}

/* Content Section */
.content-section {
    background-color: var(--white);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.result-section {
    background-color: var(--white);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    min-height: 200px;
}

.result-section pre {
    background-color: var(--light-color);
    padding: 1rem;
    border-radius: var(--border-radius);
    overflow-x: auto;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background-color: var(--white);
    margin: 5% auto;
    padding: 2rem;
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 500px;
    position: relative;
    animation: slideDown 0.3s ease;
}

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

.close {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 2rem;
    font-weight: bold;
    color: var(--secondary-color);
    cursor: pointer;
    transition: var(--transition);
}

.close:hover {
    color: var(--dark-color);
}

/* Forms */
.auth-form h2 {
    margin-bottom: 1.5rem;
    color: var(--dark-color);
}

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

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

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.form-group small {
    display: block;
    margin-top: 0.25rem;
    color: var(--secondary-color);
    font-size: 0.875rem;
}

.form-links {
    margin-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-links a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 0.9rem;
}

.form-links a:hover {
    text-decoration: underline;
}

.message {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: var(--border-radius);
    display: none;
}

.message.success {
    display: block;
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    display: block;
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 3000;
}

.spinner {
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top: 4px solid var(--white);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--dark-color);
        flex-direction: column;
        padding: 1rem;
        gap: 0;
    }

    .nav-menu.active {
        display: flex;
    }

    .dropdown-content {
        position: static;
        display: none;
        box-shadow: none;
        background-color: rgba(255, 255, 255, 0.1);
        margin-top: 0;
    }

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

    .dropdown-content a {
        color: var(--white);
        padding-left: 2rem;
    }

    .auth-section {
        width: 100%;
        flex-direction: column;
        padding-top: 1rem;
        border-top: 1px solid rgba(255, 255, 255, 0.1);
    }

    h1 {
        font-size: 2rem;
    }

    .card-grid {
        grid-template-columns: 1fr;
    }

    .modal-content {
        margin: 10% auto;
        width: 95%;
    }
}

@media (max-width: 480px) {
    .nav-container {
        padding: 1rem;
    }

    .nav-brand {
        font-size: 1.25rem;
    }

    h1 {
        font-size: 1.75rem;
    }

    .lead {
        font-size: 1.1rem;
    }

    .content-section,
    .result-section {
        padding: 1rem;
    }
}