/* ===== CSS Variables ===== */
:root {
    /* Colors */
    --color-primary: #3b82f6;
    --color-primary-hover: #2563eb;
    --color-primary-light: #dbeafe;
    --color-secondary: #64748b;
    --color-success: #10b981;
    --color-success-light: #d1fae5;
    --color-warning: #f59e0b;
    --color-warning-light: #fef3c7;
    --color-danger: #ef4444;
    --color-danger-light: #fee2e2;
    
    /* Backgrounds */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-dark: #1e293b;
    --bg-sidebar: #0f172a;
    
    /* Text */
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;
    --text-inverse: #ffffff;
    
    /* Borders */
    --border-color: #e2e8f0;
    --border-color-dark: #cbd5e1;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    /* Spacing */
    --sidebar-width: 260px;
    --sidebar-collapsed: 70px;
    --header-height: 64px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;
}

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

html {
    font-size: 14px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: inherit;
    text-decoration: none;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

input, select, textarea {
    font-family: inherit;
    font-size: inherit;
}

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

.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-between {
    justify-content: space-between;
}

.gap-1 { gap: 0.25rem; }
.gap-2 { gap: 0.5rem; }
.gap-3 { gap: 0.75rem; }
.gap-4 { gap: 1rem; }

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

/* ===== Login Screen ===== */
.login-screen {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--bg-sidebar) 0%, #1a365d 100%);
    padding: 1rem;
}

.login-container {
    width: 100%;
    max-width: 400px;
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    padding: 2.5rem;
}

.login-header {
    text-align: center;
    margin-bottom: 2rem;
}

.login-header .logo {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
}

.login-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.login-header p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

/* ===== App Layout ===== */
.app {
    display: flex;
    min-height: 100vh;
}

/* ===== Sidebar ===== */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-sidebar);
    color: var(--text-inverse);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: 100;
    transition: width var(--transition-normal);
}

.sidebar-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    padding: 0 1.25rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

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

.sidebar-header .logo-text {
    font-size: 1rem;
    font-weight: 500;
    margin-left: 0.75rem;
    color: var(--text-inverse);
    opacity: 0.9;
}

.sidebar-nav {
    flex: 1;
    padding: 1rem 0.75rem;
    overflow-y: auto;
}

.nav-item {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    border-radius: var(--radius-md);
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 0.25rem;
    transition: all var(--transition-fast);
}

.nav-item:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-inverse);
}

.nav-item.active {
    background: var(--color-primary);
    color: var(--text-inverse);
}

.nav-icon {
    width: 20px;
    height: 20px;
    margin-right: 0.75rem;
    flex-shrink: 0;
}

.sidebar-footer {
    padding: 1rem 1.25rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.user-info {
    display: flex;
    align-items: center;
    margin-bottom: 0.75rem;
}

.user-avatar {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-full);
    background: var(--color-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    margin-right: 0.75rem;
}

.user-details {
    display: flex;
    flex-direction: column;
}

.user-name {
    font-weight: 500;
    font-size: 0.875rem;
}

.user-role {
    font-size: 0.75rem;
    color: rgba(255, 255, 255, 0.6);
}

/* ===== Main Content ===== */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: margin-left var(--transition-normal);
}

.main-header {
    height: var(--header-height);
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1.5rem;
    position: sticky;
    top: 0;
    z-index: 50;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.sidebar-toggle {
    display: none;
    width: 40px;
    height: 40px;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.sidebar-toggle:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.sidebar-toggle svg {
    width: 24px;
    height: 24px;
}

.page-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.search-box {
    position: relative;
    width: 280px;
}

.search-box .search-icon {
    position: absolute;
    left: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    color: var(--text-tertiary);
}

.search-box input {
    width: 100%;
    padding: 0.625rem 1rem 0.625rem 2.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: all var(--transition-fast);
}

.search-box input:focus {
    outline: none;
    border-color: var(--color-primary);
    background: var(--bg-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

.content-area {
    flex: 1;
    padding: 1.5rem;
    overflow-y: auto;
}

/* ===== Responsive ===== */

/* Tablet (bis 1024px) */
@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-100%);
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .sidebar-toggle {
        display: flex;
    }
    
    .search-box {
        width: 200px;
    }
}

/* Mobile Landscape (bis 768px) */
@media (max-width: 768px) {
    :root {
        --sidebar-width: 280px;
        --header-height: 56px;
    }
    
    .login-container {
        padding: 1.5rem;
        margin: 1rem;
    }
    
    .login-header .logo {
        font-size: 1.75rem;
    }
    
    .login-header h1 {
        font-size: 1.25rem;
    }
    
    .main-header {
        padding: 0 1rem;
    }
    
    .page-title {
        font-size: 1.125rem;
    }
    
    .search-box {
        width: 160px;
    }
    
    .content-area {
        padding: 1rem;
    }
}

/* Mobile Portrait (bis 640px) */
@media (max-width: 640px) {
    html {
        font-size: 13px;
    }
    
    .search-box {
        display: none;
    }
    
    .content-area {
        padding: 0.75rem;
    }
    
    .header-left {
        gap: 0.5rem;
    }
    
    .page-title {
        font-size: 1rem;
        max-width: 150px;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }
    
    /* Sidebar overlay */
    .sidebar {
        width: 85vw;
        max-width: 300px;
    }
    
    .sidebar-header {
        padding: 0 1rem;
    }
    
    .sidebar-nav {
        padding: 0.75rem 0.5rem;
    }
    
    .nav-item {
        padding: 0.875rem 1rem;
    }
    
    .sidebar-footer {
        padding: 0.75rem 1rem;
    }
}

/* Sidebar Backdrop für Mobile */
.sidebar-backdrop {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 99;
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.sidebar-backdrop.visible {
    display: block;
    opacity: 1;
}

/* Touch-optimierte Scrollbars auf Mobile */
@media (max-width: 768px) {
    * {
        -webkit-tap-highlight-color: transparent;
    }
    
    ::-webkit-scrollbar {
        width: 4px;
        height: 4px;
    }
    
    ::-webkit-scrollbar-track {
        background: transparent;
    }
    
    ::-webkit-scrollbar-thumb {
        background: var(--border-color);
        border-radius: 4px;
    }
}