/* CSS Reset */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* CSS Variables */
:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-background: #ffffff;
    --color-background-alt: #f9fafb;
    --color-border: #e5e7eb;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --max-width: 1200px;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 2rem;
    --spacing-xl: 4rem;
}

/* Base Styles */
html {
    font-size: 16px;
    line-height: 1.5;
}

body {
    font-family: var(--font-family);
    color: var(--color-text);
    background-color: var(--color-background);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md) var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
}

nav ul {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

nav a {
    text-decoration: none;
    color: var(--color-text-light);
    font-weight: 500;
    transition: color 0.2s ease;
}

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

/* Main Content */
main {
    flex: 1;
    padding: var(--spacing-xl) var(--spacing-lg);
    max-width: var(--max-width);
    margin: 0 auto;
    width: 100%;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: var(--spacing-xl) 0;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
}

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

/* Footer */
footer {
    background-color: var(--color-background-alt);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-lg);
    text-align: center;
}

footer p {
    color: var(--color-text-light);
    font-size: 0.875rem;
}

/* Login Section */
.login-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-background-alt);
    padding: var(--spacing-lg);
}

.login-card {
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: var(--spacing-xl);
    width: 100%;
    max-width: 400px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.login-logo {
    display: block;
    max-width: 200px;
    height: auto;
    margin: 0 auto var(--spacing-lg);
}

.login-card h2 {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

/* Form Styles */
.form-group {
    margin-bottom: var(--spacing-md);
}

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

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

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

/* Button Styles */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    font-family: inherit;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.btn-primary {
    width: 100%;
    background-color: var(--color-primary);
    color: white;
}

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

/* Error Message */
.error-message {
    color: #dc2626;
    font-size: 0.875rem;
    margin-bottom: var(--spacing-md);
    min-height: 1.25rem;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* App Content Wrapper */
.app-content {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Social Login Buttons */
.social-login {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.btn-social {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    font-weight: 500;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn-social:active {
    transform: scale(0.98);
}

.btn-google {
    background-color: #ffffff;
    color: #757575;
    border: 1px solid var(--color-border);
}

.btn-google:hover {
    background-color: #f8f9fa;
    border-color: #dadce0;
}

.btn-apple {
    background-color: #000000;
    color: #ffffff;
    border: 1px solid #000000;
}

.btn-apple:hover {
    background-color: #1a1a1a;
}

.btn-github {
    background-color: #24292e;
    color: #ffffff;
    border: 1px solid #24292e;
}

.btn-github:hover {
    background-color: #2f363d;
}

.btn-microsoft {
    background-color: #ffffff;
    color: #5e5e5e;
    border: 1px solid var(--color-border);
}

.btn-microsoft:hover {
    background-color: #f8f9fa;
    border-color: #dadce0;
}

.social-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

/* Login Divider */
.login-divider {
    display: flex;
    align-items: center;
    margin: var(--spacing-lg) 0;
}

.login-divider::before,
.login-divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background-color: var(--color-border);
}

.login-divider span {
    padding: 0 var(--spacing-md);
    color: var(--color-text-light);
    font-size: 0.875rem;
}

/* User Email Display */
.user-email {
    color: var(--color-text-light);
    font-size: 0.875rem;
    margin-top: var(--spacing-sm);
}

/* Dev Login (hidden by default) */
.dev-login {
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px dashed var(--color-border);
}

.dev-login .login-divider span {
    color: #f59e0b;
    font-weight: 500;
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
}

/* Responsive Design */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    nav ul {
        gap: var(--spacing-md);
    }

    .hero h2 {
        font-size: 2rem;
    }

    .login-card {
        padding: var(--spacing-lg);
    }
}