/* Global Styles for Grammar Guru Frontend */

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

/* Root Variables */
:root {
    /* Colors */
    --primary-color: #3b82f6;
    --primary-dark: #2563eb;
    --primary-light: #60a5fa;
    --secondary-color: #6b7280;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --info-color: #06b6d4;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-card: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
    
    /* Font Sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Transitions */
    --transition: all 0.2s ease-in-out;
    --transition-slow: all 0.3s ease-in-out;
    
    /* Z-index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal: 1040;
    --z-popover: 1050;
    --z-tooltip: 1060;
}

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

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: #1f2937;
    background-color: #ffffff;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

@media (min-width: 640px) {
    .container {
        padding: 0 var(--space-6);
    }
}

@media (min-width: 1024px) {
    .container {
        padding: 0 var(--space-8);
    }
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: var(--space-4);
    color: #111827;
}

h1 {
    font-size: var(--text-4xl);
}

h2 {
    font-size: var(--text-3xl);
}

h3 {
    font-size: var(--text-2xl);
}

h4 {
    font-size: var(--text-xl);
}

h5 {
    font-size: var(--text-lg);
}

h6 {
    font-size: var(--text-base);
}

p {
    margin-bottom: var(--space-4);
    color: #4b5563;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-size: var(--text-sm);
    font-weight: 500;
    text-decoration: none;
    border-radius: var(--radius);
    border: 1px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    background: none;
    font-family: inherit;
    line-height: 1.5;
    min-height: 40px;
}

.btn:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Button Variants */
.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-dark);
    border-color: var(--primary-dark);
    color: white;
    text-decoration: none;
}

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

.btn-secondary:hover:not(:disabled) {
    background-color: #4b5563;
    border-color: #4b5563;
    color: white;
    text-decoration: none;
}

.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-outline:hover:not(:disabled) {
    background-color: var(--primary-color);
    color: white;
    text-decoration: none;
}

.btn-ghost {
    background-color: transparent;
    color: var(--primary-color);
    border-color: transparent;
}

.btn-ghost:hover:not(:disabled) {
    background-color: #f3f4f6;
    color: var(--primary-dark);
    text-decoration: none;
}

/* Button Sizes */
.btn-small {
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-xs);
    min-height: 32px;
}

.btn-large {
    padding: var(--space-4) var(--space-8);
    font-size: var(--text-base);
    min-height: 48px;
}

.btn-full {
    width: 100%;
}

/* Button Icons */
.btn-icon {
    font-size: var(--text-sm);
}

/* Loading Spinner */
.spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid transparent;
    border-top: 2px solid currentColor;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Navigation */
.navbar {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid #e5e7eb;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: var(--z-fixed);
    transition: var(--transition);
}

.navbar:hover {
    background-color: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-md);
}

.nav-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) 0;
    min-height: 64px;
}

.nav-brand {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: var(--space-2);
    text-decoration: none;
    color: inherit;
    min-height: 40px;
    transition: var(--transition);
    padding: var(--space-2) 0;
}

.nav-brand:hover {
    transform: translateX(2px);
}

.nav-brand:hover .brand-text {
    color: var(--primary-color);
}

.logo {
    width: 32px;
    height: 32px;
    flex-shrink: 0;
    transition: var(--transition);
}

.nav-brand:hover .logo {
    transform: scale(1.05);
}

.brand-text {
    font-size: var(--text-xl);
    font-weight: 600;
    color: #111827;
    line-height: 1;
    transition: var(--transition);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    min-height: 40px;
}

/* Navigation specific button adjustments */
.nav-links .btn {
    min-height: 36px;
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-sm);
    transition: var(--transition);
}

.nav-links .btn:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.nav-links #logoutBtn {
    background-color: transparent;
    border: 1px solid #ef4444;
    color: #ef4444;
}

.nav-links #logoutBtn:hover {
    background-color: #ef4444;
    color: white;
    border-color: #dc2626;
}

.nav-link {
    font-size: var(--text-sm);
    font-weight: 500;
    color: #4b5563;
    text-decoration: none;
    transition: var(--transition);
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    min-height: 36px;
    position: relative;
    overflow: hidden;
}

.nav-link::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s ease;
}

.nav-link:hover {
    color: var(--primary-color);
    text-decoration: none;
    background-color: rgba(59, 130, 246, 0.05);
    transform: translateY(-1px);
}

.nav-link:hover::before {
    width: 100%;
}

.nav-link.active {
    color: var(--primary-color);
    background-color: rgba(59, 130, 246, 0.1);
    font-weight: 600;
}

.nav-link.active::before {
    width: 100%;
}

/* Mobile Menu */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    cursor: pointer;
    padding: var(--space-2);
    border-radius: var(--radius);
    transition: var(--transition);
    background: transparent;
    border: none;
}

.mobile-menu-toggle:hover {
    background-color: rgba(59, 130, 246, 0.05);
    transform: scale(1.05);
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: #4b5563;
    transition: var(--transition);
}

@media (max-width: 768px) {
    .nav-content {
        min-height: 56px;
        padding: var(--space-3) 0;
        position: relative;
    }
    
    .nav-brand {
        min-height: 32px;
    }
    
    .brand-text {
        font-size: var(--text-lg);
    }
    
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        border: 1px solid #e5e7eb;
        border-top: none;
        box-shadow: var(--shadow-lg);
        flex-direction: column;
        padding: var(--space-4);
        gap: var(--space-2);
        z-index: var(--z-dropdown);
    }
    
    .nav-links.mobile-open {
        display: flex;
    }
    
    .nav-links .nav-link {
        width: 100%;
        justify-content: center;
        padding: var(--space-3) var(--space-4);
        border-radius: var(--radius);
    }
    
    .nav-links .btn {
        width: 100%;
        justify-content: center;
        margin-top: var(--space-2);
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .mobile-menu-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .mobile-menu-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .mobile-menu-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }
}

/* Forms */
.form-group {
    margin-bottom: var(--space-6);
}

.form-label {
    display: block;
    font-size: var(--text-sm);
    font-weight: 500;
    color: #374151;
    margin-bottom: var(--space-2);
}

.form-input {
    width: 100%;
    padding: var(--space-3);
    font-size: var(--text-sm);
    border: 1px solid #d1d5db;
    border-radius: var(--radius);
    background-color: white;
    transition: var(--transition);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-input::placeholder {
    color: #9ca3af;
}

.form-error {
    font-size: var(--text-xs);
    color: var(--error-color);
    margin-top: var(--space-1);
    display: block;
}

.form-help {
    font-size: var(--text-xs);
    color: var(--secondary-color);
    margin-top: var(--space-1);
}

/* Alerts */
.alert {
    padding: var(--space-4);
    border-radius: var(--radius);
    margin-bottom: var(--space-4);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.alert-content {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.alert-close {
    background: none;
    border: none;
    font-size: var(--text-lg);
    cursor: pointer;
    padding: 0;
    color: inherit;
    opacity: 0.7;
}

.alert-close:hover {
    opacity: 1;
}

.alert-success {
    background-color: #ecfdf5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}

.alert-error {
    background-color: #fef2f2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.alert-warning {
    background-color: #fffbeb;
    color: #92400e;
    border: 1px solid #fed7aa;
}

.alert-info {
    background-color: #f0f9ff;
    color: #1e40af;
    border: 1px solid #bae6fd;
}

/* Cards */
.card {
    background-color: white;
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    box-shadow: var(--shadow);
    border: 1px solid #e5e7eb;
}

/* Grid System */
.grid {
    display: grid;
    gap: var(--space-6);
}

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

.grid-cols-2 {
    grid-template-columns: repeat(2, 1fr);
}

.grid-cols-3 {
    grid-template-columns: repeat(3, 1fr);
}

.grid-cols-4 {
    grid-template-columns: repeat(4, 1fr);
}

@media (max-width: 768px) {
    .grid-cols-2,
    .grid-cols-3,
    .grid-cols-4 {
        grid-template-columns: 1fr;
    }
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.text-left {
    text-align: left;
}

.text-right {
    text-align: right;
}

.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Gradient Text */
.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Loading States */
.loading-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-16);
    text-align: center;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f4f6;
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: var(--space-4);
}

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

.fade-in {
    animation: fadeIn 0.5s ease-out;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.slide-up {
    animation: slideUp 0.6s ease-out;
}

/* Print Styles */
@media print {
    .navbar,
    .mobile-menu-toggle,
    .btn,
    .alert {
        display: none !important;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
    
    .container {
        max-width: none;
        padding: 0;
    }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #0066cc;
        --primary-dark: #004499;
    }
    
    .btn-outline {
        border-width: 2px;
    }
    
    .form-input {
        border-width: 2px;
    }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}