:root { 
    /* --- 1. GENEL RENKLER --- */
    --brand-yellow: #F5C300; 
    --brand-bg: #000000; 
    --panel-bg: #161616; 
    --text-main: #ffffff;
    --text-muted: #888888;
    --border-color: #333333;
    
    /* --- 2. GİRİŞ EKRANI (LOGIN) --- */
    --login-bg: #000000;
    --keypad-btn-bg: rgba(255,255,255,0.1);
    --keypad-text: #ffffff;
    
    /* --- 3. MENÜ (SIDEBAR) --- */
    --sidebar-bg: #111111;
    --sidebar-text: #888888;
    --sidebar-active-bg: #F5C300;
    --sidebar-active-text: #000000;

    /* --- 4. BUTONLAR & DURUMLAR --- */
    --btn-primary: #F5C300;
    --btn-primary-text: #000000;
    --btn-danger: #e74c3c;
    --btn-success: #2ecc71;
    
    /* Sabit Yardımcılar */
    --brand-dark: #2D2D2D; 
    --gray-light: #e0e0e0; 
}

/* Genel Reset */
* { box-sizing: border-box; } 

body { 
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; 
    margin: 0; padding: 0; 
    background-color: var(--brand-bg);
    color: var(--text-main);
    height: 100vh; 
    overflow: hidden; 
    transition: background-color 0.3s ease, color 0.3s ease;
}