:root {
    --color-primary: #0b3b60;
    --color-primary-hover: #072740;
    --color-accent: #0284c7;
    --color-accent-light: #e0f2fe;
    --color-accent-hover: #0369a1;
    
    --color-bg-body: #f8fafc;
    --color-bg-surface: #ffffff;
    --color-bg-sidebar: #0b3b60;
    --color-bg-sidebar-hover: rgba(255, 255, 255, 0.08);
    --color-bg-sidebar-active: #0284c7;
    
    --color-border: #e2e8f0;
    --color-border-focus: #0284c7;
    
    --color-text-main: #0f172a;
    --color-text-muted: #64748b;
    --color-text-inverse: #ffffff;
    
    --color-risk-green: #16a34a;
    --color-risk-green-bg: #f0fdf4;
    --color-risk-green-border: #bbf7d0;
    
    --color-risk-yellow: #d97706;
    --color-risk-yellow-bg: #fffbeb;
    --color-risk-yellow-border: #fde68a;
    
    --color-risk-red: #dc2626;
    --color-risk-red-bg: #fef2f2;
    --color-risk-red-border: #fecaca;
    
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-mono: "JetBrains Mono", "Fira Code", Consolas, monospace;
    
    --sidebar-width: 260px;
    --header-height: 64px;
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --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);
}

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

body {
    font-family: var(--font-sans);
    font-size: 14px;
    line-height: 1.5;
    color: var(--color-text-main);
    background-color: var(--color-bg-body);
    -webkit-font-smoothing: antialiased;
}

.app-layout {
    display: flex;
    min-height: 100vh;
}

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

.sidebar-brand {
    height: var(--header-height);
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 0 20px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    font-weight: 700;
    font-size: 1.15rem;
    letter-spacing: 0.3px;
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    padding: 16px 12px;
    gap: 6px;
    flex: 1;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 14px;
    border-radius: var(--radius-md);
    color: rgba(255, 255, 255, 0.78);
    text-decoration: none;
    font-weight: 500;
    transition: background-color 0.15s ease, color 0.15s ease;
}

.nav-link:hover {
    background-color: var(--color-bg-sidebar-hover);
    color: var(--color-text-inverse);
}

.nav-link.active {
    background-color: var(--color-bg-sidebar-active);
    color: var(--color-text-inverse);
}

.nav-icon {
    font-size: 1.2rem;
    width: 22px;
    text-align: center;
}

.sidebar-footer {
    padding: 16px 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    font-size: 0.78rem;
    color: rgba(255, 255, 255, 0.55);
}

.main-viewport {
    margin-left: var(--sidebar-width);
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.top-header {
    height: var(--header-height);
    background-color: var(--color-bg-surface);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 28px;
    position: sticky;
    top: 0;
    z-index: 90;
}

.page-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-primary);
}

.header-status {
    display: flex;
    align-items: center;
    gap: 14px;
}

.page-content {
    padding: 24px 28px;
    flex: 1;
}

/* ==========================================================================
   THEME: ENTERPRISE DARK MODE (ТОКЕНЫ СИТУАЦИОННОГО ЦЕНТРА ПОЧТАТЕХ) */
body.theme-dark {
    --color-primary: #38bdf8;
    --color-primary-hover: #0284c7;
    --color-accent: #0284c7;
    --color-accent-light: rgba(2, 132, 199, 0.15);
    --color-accent-hover: #38bdf8;

    --color-bg-body: #050811;
    --color-bg-surface: #0a0f1d;
    --color-bg-surface-elevated: #0f172a;
    --color-bg-sidebar: #03060d;
    --color-bg-sidebar-hover: rgba(255, 255, 255, 0.05);
    --color-bg-sidebar-active: #0284c7;

    --color-border: #172033;
    --color-border-subtle: #1e293b;
    --color-border-focus: #38bdf8;

    --color-text-main: #f1f5f9;
    --color-text-muted: #94a3b8;
    --color-text-inverse: #ffffff;

    --color-risk-green: #10b981;
    --color-risk-green-bg: rgba(16, 185, 129, 0.12);
    --color-risk-green-border: rgba(16, 185, 129, 0.35);

    --color-risk-yellow: #f59e0b;
    --color-risk-yellow-bg: rgba(245, 158, 11, 0.12);
    --color-risk-yellow-border: rgba(245, 158, 11, 0.35);

    --color-risk-red: #f43f5e;
    --color-risk-red-bg: rgba(244, 63, 94, 0.12);
    --color-risk-red-border: rgba(244, 63, 94, 0.35);

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 14px -1px rgba(0, 0, 0, 0.5), 0 2px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-glow-cyan: 0 0 20px rgba(56, 189, 248, 0.15);
    --shadow-glow-amber: 0 0 20px rgba(245, 158, 11, 0.15);
    --shadow-glow-red: 0 0 20px rgba(244, 63, 94, 0.18);
}

body.theme-dark .top-header {
    background-color: #070b16;
    border-bottom-color: #172033;
}

body.theme-dark .sidebar {
    background-color: #03060d;
    border-right: 1px solid #172033;
}

body.theme-dark .sidebar-brand {
    border-bottom-color: #172033;
}

body.theme-dark .sidebar-footer {
    border-top-color: #172033;
}