/**
 * Modern Community Platform - Main Stylesheet
 * Mobile-First, PWA-ready Design System
 */

:root {
    /* Colors */
    --color-primary: #007bff;
    --color-primary-dark: #0056b3;
    --color-primary-light: #66b3ff;
    --color-secondary: #6c757d;
    --color-success: #28a745;
    --color-danger: #dc3545;
    --color-warning: #ffc107;
    --color-info: #17a2b8;
    
    /* Grays */
    --color-gray-50: #f8f9fa;
    --color-gray-100: #e9ecef;
    --color-gray-200: #dee2e6;
    --color-gray-300: #ced4da;
    --color-gray-400: #adb5bd;
    --color-gray-500: #6c757d;
    --color-gray-600: #495057;
    --color-gray-700: #343a40;
    --color-gray-800: #212529;
    --color-gray-900: #0d1117;
    
    /* Backgrounds */
    --bg-primary: #ffffff;
    --bg-secondary: var(--color-gray-50);
    --bg-dark: var(--color-gray-800);
    
    /* Text */
    --text-primary: var(--color-gray-900);
    --text-secondary: var(--color-gray-600);
    --text-muted: var(--color-gray-500);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    
    /* Borders */
    --border-radius-sm: 0.25rem;
    --border-radius-md: 0.5rem;
    --border-radius-lg: 0.75rem;
    --border-radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --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);
    
    /* Layout */
    --nav-height: 64px;
    --container-max-width: 1200px;
    --content-padding: var(--spacing-md);
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;
    
    /* Z-index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

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

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Navigation */
.main-nav {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    background: var(--bg-primary);
    border-bottom: 1px solid var(--color-gray-200);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--nav-height);
    gap: var(--spacing-lg);
}

.nav-brand {
    display: flex;
    align-items: center;
    flex-shrink: 0;
}

.brand-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 600;
    font-size: var(--font-size-lg);
    transition: opacity var(--transition-fast);
}

.brand-link:hover {
    opacity: 0.8;
}

.brand-icon {
    width: 32px;
    height: 32px;
    color: var(--color-primary);
}

.brand-logo {
    height: 40px;
    width: auto;
    max-width: 200px;
    object-fit: contain;
    flex-shrink: 0;
}

.brand-text {
    display: none;
}

@media (min-width: 640px) {
    .brand-text {
        display: inline;
    }
}

.nav-menu {
    display: none;
    align-items: center;
    gap: var(--spacing-sm);
    flex: 1;
    justify-content: center;
}

@media (min-width: 768px) {
    .nav-menu {
        display: flex;
    }
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    font-weight: 500;
    border-radius: var(--border-radius-md);
    transition: all var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    color: var(--color-primary);
    background-color: var(--color-gray-50);
}

.nav-link.active {
    color: var(--color-primary);
    background-color: rgba(0, 123, 255, 0.1);
}

.nav-icon {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}

.nav-text {
    display: none;
}

@media (min-width: 1024px) {
    .nav-text {
        display: inline;
    }
}

/* Navigation Dropdown (Untermenü) */
.nav-item-dropdown {
    position: relative;
}

.nav-link-dropdown {
    position: relative;
}

.nav-link-dropdown .chevron-icon {
    width: 14px;
    height: 14px;
    margin-left: auto;
    transition: transform var(--transition-fast);
}

.nav-item-dropdown:hover .nav-link-dropdown .chevron-icon,
.nav-item-dropdown.active .nav-link-dropdown .chevron-icon {
    transform: rotate(180deg);
}

.nav-submenu {
    position: absolute;
    top: calc(100% + var(--spacing-xs));
    left: 0;
    min-width: 220px;
    background: var(--bg-primary);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-xs);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-base);
    z-index: var(--z-dropdown);
    max-height: 80vh;
    overflow-y: auto;
}

.nav-item-dropdown:hover .nav-submenu,
.nav-item-dropdown.active .nav-submenu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.nav-submenu-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    border-radius: var(--border-radius-sm);
    transition: background-color var(--transition-fast);
}

.nav-submenu-link:hover {
    background-color: var(--color-gray-50);
    color: var(--color-primary);
}

.nav-submenu-link.active {
    background-color: rgba(0, 123, 255, 0.1);
    color: var(--color-primary);
}

.nav-submenu-icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    color: var(--text-secondary);
}

.nav-submenu-link:hover .nav-submenu-icon,
.nav-submenu-link.active .nav-submenu-icon {
    color: var(--color-primary);
}

.nav-user {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-shrink: 0;
}

.user-menu-wrapper {
    position: relative;
}

.user-menu-trigger {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-xs);
    background: none;
    border: none;
    cursor: pointer;
    border-radius: var(--border-radius-full);
    transition: background-color var(--transition-fast);
}

.user-menu-trigger:hover {
    background-color: var(--color-gray-100);
}

.user-avatar {
    width: 36px;
    height: 36px;
    border-radius: var(--border-radius-full);
    background: var(--color-primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: var(--font-size-sm);
}

.chevron-icon {
    width: 16px;
    height: 16px;
    color: var(--text-secondary);
    display: none;
}

@media (min-width: 768px) {
    .chevron-icon {
        display: block;
    }
}

.user-menu-dropdown {
    position: absolute;
    top: calc(100% + var(--spacing-xs));
    right: 0;
    min-width: 200px;
    background: var(--bg-primary);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-xs);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-base);
    z-index: var(--z-dropdown);
}

.user-menu-wrapper.active .user-menu-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.user-menu-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    border-radius: var(--border-radius-sm);
    transition: background-color var(--transition-fast);
}

.user-menu-item:hover {
    background-color: var(--color-gray-50);
}

.user-menu-icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

.mobile-menu-toggle {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: var(--spacing-sm);
    background: none;
    border: none;
    cursor: pointer;
    width: 40px;
    height: 40px;
    justify-content: center;
}

@media (min-width: 768px) {
    .mobile-menu-toggle {
        display: none;
    }
}

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

.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

.mobile-nav {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-primary);
    transform: translateX(-100%);
    transition: transform var(--transition-base);
    z-index: var(--z-fixed);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
}

.mobile-nav.active {
    transform: translateX(0);
}

.mobile-nav-content {
    padding: var(--spacing-md);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.mobile-nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    text-decoration: none;
    color: var(--text-primary);
    font-size: var(--font-size-base);
    font-weight: 500;
    border-radius: var(--border-radius-md);
    transition: background-color var(--transition-fast);
}

.mobile-nav-link:hover,
.mobile-nav-link:active {
    background-color: var(--color-gray-50);
}

.mobile-nav-icon {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
}

.mobile-nav-divider {
    height: 1px;
    background: var(--color-gray-200);
    margin: var(--spacing-md) 0;
}

/* Mobile Navigation Dropdown */
.mobile-nav-dropdown {
    display: flex;
    flex-direction: column;
}

.mobile-nav-link-dropdown {
    position: relative;
}

.mobile-nav-link-dropdown .chevron-icon {
    width: 16px;
    height: 16px;
    margin-left: auto;
    transition: transform var(--transition-fast);
}

.mobile-nav-dropdown.active .mobile-nav-link-dropdown .chevron-icon {
    transform: rotate(180deg);
}

.mobile-nav-submenu {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
    padding-left: var(--spacing-lg);
}

.mobile-nav-dropdown.active .mobile-nav-submenu {
    max-height: 1000px;
}

.mobile-nav-submenu-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    border-radius: var(--border-radius-md);
    transition: background-color var(--transition-fast);
}

.mobile-nav-submenu-link:hover,
.mobile-nav-submenu-link:active {
    background-color: var(--color-gray-50);
    color: var(--color-primary);
}

.mobile-nav-submenu-link.active {
    background-color: rgba(0, 123, 255, 0.1);
    color: var(--color-primary);
}

/* Main Content */
.main-content {
    flex: 1;
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: var(--spacing-lg) var(--content-padding);
    min-height: calc(100vh - var(--nav-height) - 80px);
}

@media (min-width: 768px) {
    .main-content {
        padding: var(--spacing-xl) var(--content-padding);
    }
}

/* Footer */
.main-footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--color-gray-200);
    padding: var(--spacing-lg) var(--spacing-md);
    margin-top: auto;
}

.footer-container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    text-align: center;
}

.footer-container p {
    color: var(--text-muted);
    font-size: var(--font-size-sm);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-base);
    font-weight: 500;
    text-decoration: none;
    border: 1px solid transparent;
    border-radius: var(--border-radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

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

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

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

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

.btn-sm {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--font-size-sm);
}

/* Cards */
.card {
    background: var(--bg-primary);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

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

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

.form-input {
    width: 100%;
    padding: var(--spacing-md);
    border: 1px solid var(--color-gray-300);
    border-radius: var(--border-radius-md);
    font-size: var(--font-size-base);
    font-family: inherit;
    transition: all var(--transition-fast);
    background: var(--bg-primary);
    color: var(--text-primary);
}

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

.form-input::placeholder {
    color: var(--text-muted);
}

.form-input:invalid:not(:focus):not(:placeholder-shown) {
    border-color: var(--color-danger);
}

.form-input:valid:not(:focus):not(:placeholder-shown) {
    border-color: var(--color-success);
}

.form-textarea {
    min-height: 100px;
    resize: vertical;
}

/* Alerts */
.alert {
    padding: var(--spacing-md);
    border-radius: var(--border-radius-md);
    margin-bottom: var(--spacing-lg);
    font-size: var(--font-size-sm);
    border: 1px solid transparent;
}

.alert-error {
    background-color: #f8d7da;
    color: #721c24;
    border-color: #f5c6cb;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
    border-color: #c3e6cb;
}

.alert-info {
    background-color: #d1ecf1;
    color: #0c5460;
    border-color: #bee5eb;
}

.alert-warning {
    background-color: #fff3cd;
    color: #856404;
    border-color: #ffeaa7;
}

/* Utilities */
.text-center {
    text-align: center;
}

.text-muted {
    color: var(--text-muted);
}

.text-danger {
    color: var(--color-danger);
}

.text-success {
    color: var(--color-success);
}

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }

/* Safe Area Insets für iOS */
@supports (padding: max(0px)) {
    body {
        padding-left: max(0px, env(safe-area-inset-left));
        padding-right: max(0px, env(safe-area-inset-right));
    }
    
    .main-nav {
        padding-left: max(var(--spacing-md), env(safe-area-inset-left));
        padding-right: max(var(--spacing-md), env(safe-area-inset-right));
    }
}