:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --text-color: #1f2937;
    --bg-color: #ffffff;
    --light-gray: #f3f4f6;
    --border-color: #e5e7eb;
    --max-width: 1200px;
}

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

html {
    scroll-behavior: smooth;
}

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background-color: var(--bg-color);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

nav {
    padding: 1rem 0;
}

nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand a {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

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

.nav-menu a {
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 8rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.25rem;
    opacity: 0.9;
}

.section {
    padding: 4rem 0;
}

.section:nth-child(even) {
    background-color: var(--light-gray);
}

.section h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

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

.app-card {
    background: white;
    padding: 2rem;
    border-radius: 0.75rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.app-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.app-card h3 {
    color: var(--primary-color);
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.app-card p {
    color: var(--text-color);
    margin-bottom: 1.5rem;
    opacity: 0.8;
}

.app-link {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    border-radius: 0.5rem;
    font-weight: 500;
    transition: background-color 0.3s ease;
}

.app-link:hover {
    background-color: var(--secondary-color);
    color: white;
}

footer {
    background-color: var(--text-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

.auth-button {
    background-color: var(--primary-color);
    color: white !important;
    padding: 0.5rem 1rem;
    border-radius: 0.375rem;
    transition: background-color 0.3s ease;
}

.auth-button:hover {
    background-color: var(--secondary-color);
    color: white !important;
}

.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    animation: fadeIn 0.3s;
}

.modal.show {
    display: flex;
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: var(--bg-color);
    padding: 2rem;
    border-radius: 0.5rem;
    width: 90%;
    max-width: 400px;
    position: relative;
    animation: slideIn 0.3s;
}

.close {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
    opacity: 0.5;
    transition: opacity 0.3s;
}

.close:hover {
    opacity: 1;
}

.modal h2 {
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

#auth-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

#auth-form input {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.375rem;
    font-size: 1rem;
}

#auth-form input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

#auth-form button {
    padding: 0.75rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 0.375rem;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s;
}

#auth-form button:hover {
    background-color: var(--secondary-color);
}

.divider {
    text-align: center;
    margin: 1.5rem 0;
    position: relative;
    color: var(--text-color);
    opacity: 0.5;
}

.divider::before,
.divider::after {
    content: '';
    position: absolute;
    top: 50%;
    width: 45%;
    height: 1px;
    background-color: var(--border-color);
}

.divider::before {
    left: 0;
}

.divider::after {
    right: 0;
}

.oauth-btn {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    background-color: white;
    border-radius: 0.375rem;
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: background-color 0.3s;
}

.oauth-btn:hover {
    background-color: var(--light-gray);
}

.auth-switch {
    text-align: center;
    margin-top: 1.5rem;
    color: var(--text-color);
}

.auth-switch a {
    color: var(--primary-color);
    text-decoration: none;
}

.auth-switch a:hover {
    text-decoration: underline;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-color);
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        gap: 1rem;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero {
        padding: 4rem 0;
    }
    
    .modal-content {
        width: 95%;
        padding: 1.5rem;
    }
}