/* ===== Modern German Learning Platform - Global Styles ===== */

/* CSS Variables */
:root {
    /* Light Theme Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #212529;
    --text-secondary: #495057;
    --text-tertiary: #6c757d;
    --border-color: #dee2e6;

    /* Brand Colors */
    --brand-primary: #4361ee;
    --brand-secondary: #3f37c9;
    --brand-accent: #7209b7;
    --success: #06ffa5;
    --warning: #ffbe0b;
    --danger: #f72585;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #4361ee 0%, #7209b7 100%);
    --gradient-success: linear-gradient(135deg, #06ffa5 0%, #00d084 100%);
    --gradient-card: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
    --shadow-md: 0 3px 6px rgba(0,0,0,0.15), 0 2px 4px rgba(0,0,0,0.12);
    --shadow-lg: 0 10px 20px rgba(0,0,0,0.15), 0 3px 6px rgba(0,0,0,0.10);
    --shadow-xl: 0 15px 25px rgba(0,0,0,0.15), 0 5px 10px rgba(0,0,0,0.05);
    --shadow-glow: 0 0 20px rgba(67, 97, 238, 0.3);

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-2xl: 2rem;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

    /* 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;

    /* Z-Index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* Dark Theme */
[data-theme="dark"] {
    --bg-primary: #0f0f0f;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #2a2a2a;
    --text-primary: #ffffff;
    --text-secondary: #e0e0e0;
    --text-tertiary: #a0a0a0;
    --border-color: #333333;
    --gradient-card: linear-gradient(135deg, #1a1a1a 0%, #2a2a2a 100%);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.5), 0 1px 2px rgba(0,0,0,0.4);
    --shadow-md: 0 3px 6px rgba(0,0,0,0.5), 0 2px 4px rgba(0,0,0,0.4);
    --shadow-lg: 0 10px 20px rgba(0,0,0,0.5), 0 3px 6px rgba(0,0,0,0.4);
    --shadow-xl: 0 15px 25px rgba(0,0,0,0.5), 0 5px 10px rgba(0,0,0,0.3);
    --shadow-glow: 0 0 20px rgba(67, 97, 238, 0.5);
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition-base), color var(--transition-base);
    min-height: 100vh;
    overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-4xl); }
h3 { font-size: var(--text-3xl); }
h4 { font-size: var(--text-2xl); }
h5 { font-size: var(--text-xl); }
h6 { font-size: var(--text-lg); }

p {
    margin-bottom: var(--spacing-md);
}

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

a:hover {
    color: var(--brand-secondary);
}

/* Header Styles */
.header {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    background: var(--bg-primary);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.9);
    border-bottom: 1px solid var(--border-color);
    transition: all var(--transition-base);
}

[data-theme="dark"] .header {
    background: rgba(15, 15, 15, 0.9);
}

.header-container {
    max-width: 1440px;
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.header-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--text-primary);
}

.header-logo img {
    width: 40px;
    height: 40px;
}

.header-nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.nav-link {
    padding: var(--spacing-sm) var(--spacing-lg);
    color: var(--text-secondary);
    font-weight: 500;
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    background: var(--bg-secondary);
    color: var(--brand-primary);
}

.nav-link.active {
    background: var(--gradient-secondary);
    color: white;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.header-progress {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
}

.progress-circle {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: var(--text-xs);
    font-weight: 700;
}

.theme-toggle {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    background: var(--bg-secondary);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    color: var(--text-primary);
}

.theme-toggle:hover {
    background: var(--gradient-secondary);
    color: white;
    transform: scale(1.05);
}

.menu-toggle {
    display: none;
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    border: none;
    cursor: pointer;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all var(--transition-fast);
}

/* Container */
.container {
    max-width: 1440px;
    margin: 0 auto;
    padding: var(--spacing-xl);
}

/* Cards */
.card {
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    border: 1px solid var(--border-color);
}

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

.glass-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

[data-theme="dark"] .glass-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

/* Buttons */
.btn {
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-lg);
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    font-size: var(--text-base);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(45deg, transparent, rgba(255,255,255,0.1), transparent);
    transform: translateX(-100%);
    transition: transform 0.6s;
}

.btn:hover::before {
    transform: translateX(100%);
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: var(--bg-tertiary);
}

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

.btn-outline {
    background: transparent;
    border: 2px solid var(--brand-primary);
    color: var(--brand-primary);
}

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

/* Input & Form Elements */
.input-group {
    margin-bottom: var(--spacing-lg);
}

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

.input {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-secondary);
    border: 2px solid transparent;
    border-radius: var(--radius-lg);
    font-size: var(--text-base);
    transition: all var(--transition-fast);
    color: var(--text-primary);
}

.input:focus {
    outline: none;
    border-color: var(--brand-primary);
    box-shadow: 0 0 0 4px rgba(67, 97, 238, 0.1);
}

/* Badge */
.badge {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    font-weight: 600;
}

.badge-primary {
    background: var(--gradient-secondary);
    color: white;
}

.badge-success {
    background: var(--gradient-success);
    color: white;
}

/* Progress Bar */
.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    overflow: hidden;
    position: relative;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
    position: relative;
    overflow: hidden;
}

.progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: linear-gradient(
        90deg,
        transparent,
        rgba(255, 255, 255, 0.3),
        transparent
    );
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

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

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

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

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

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

@keyframes bounce {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

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

.animate-slideIn {
    animation: slideIn 0.5s ease-out;
}

.animate-pulse {
    animation: pulse 2s infinite;
}

.animate-bounce {
    animation: bounce 2s infinite;
}

/* Loading Spinner */
.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--bg-tertiary);
    border-top: 4px solid var(--brand-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Toast Notifications */
.toast {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    z-index: var(--z-popover);
    animation: slideIn 0.3s ease-out;
}

.toast-success {
    background: var(--gradient-success);
    color: white;
}

.toast-error {
    background: var(--danger);
    color: white;
}

/* Modal */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    z-index: var(--z-modal-backdrop);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.modal-backdrop.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    max-width: 600px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    transform: scale(0.9);
    transition: all var(--transition-base);
}

.modal-backdrop.active .modal {
    transform: scale(1);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .grid-cols-4 {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 768px) {
    .header-nav {
        display: none;
    }

    .menu-toggle {
        display: flex;
    }

    .grid-cols-3,
    .grid-cols-4 {
        grid-template-columns: repeat(2, 1fr);
    }

    h1 { font-size: var(--text-3xl); }
    h2 { font-size: var(--text-2xl); }
    h3 { font-size: var(--text-xl); }
}

@media (max-width: 480px) {
    .container {
        padding: var(--spacing-md);
    }

    .header-container {
        padding: var(--spacing-md);
    }

    .grid-cols-2,
    .grid-cols-3,
    .grid-cols-4 {
        grid-template-columns: repeat(1, 1fr);
    }

    .header-progress {
        display: none;
    }
}

/* Mobile Navigation */
.mobile-nav {
    position: fixed;
    top: 0;
    right: -300px;
    width: 300px;
    height: 100vh;
    background: var(--bg-primary);
    box-shadow: var(--shadow-xl);
    z-index: var(--z-fixed);
    transition: right var(--transition-base);
    padding: var(--spacing-xl);
}

.mobile-nav.active {
    right: 0;
}

.mobile-nav-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-top: var(--spacing-2xl);
}

.mobile-nav-link {
    padding: var(--spacing-md);
    color: var(--text-primary);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.mobile-nav-link:hover {
    background: var(--bg-secondary);
}

/* Scrollbar Styles */
::-webkit-scrollbar {
    width: 12px;
    height: 12px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--brand-primary);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--brand-secondary);
}

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

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }
.mt-5 { margin-top: var(--spacing-2xl); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }
.mb-5 { margin-bottom: var(--spacing-2xl); }

.hidden { display: none !important; }
.block { display: block !important; }
.flex { display: flex !important; }
.inline-flex { display: inline-flex !important; }

.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }

.gap-1 { gap: var(--spacing-sm); }
.gap-2 { gap: var(--spacing-md); }
.gap-3 { gap: var(--spacing-lg); }
.gap-4 { gap: var(--spacing-xl); }

.w-full { width: 100%; }
.h-full { height: 100%; }

.relative { position: relative; }
.absolute { position: absolute; }
.fixed { position: fixed; }

.top-0 { top: 0; }
.right-0 { right: 0; }
.bottom-0 { bottom: 0; }
.left-0 { left: 0; }

.z-10 { z-index: 10; }
.z-20 { z-index: 20; }
.z-30 { z-index: 30; }

/* Success States */
.success-bg {
    background: var(--gradient-success);
    color: white;
}

.error-bg {
    background: var(--danger);
    color: white;
}