:root {
    --bg-main: #f0f2f5;
    --sidebar-bg: #1a252f;
    --sidebar-text: #bdc3c7;
    --text-dark: #2c3e50;
    --text-light: #7f8c8d;
    --white: #ffffff;
    --primary: #3498db;
    --success: #27ae60;
    --warning: #f1c40f;
    --danger: #e74c3c;
    --border-color: #e1e8ed;
}

body { font-family: 'Segoe UI', system-ui, sans-serif; margin: 0; display: flex; background: var(--bg-main); color: var(--text-dark); }
a { text-decoration: none; transition: 0.2s; }

/* Sidebar */
.sidebar { width: 240px; background: var(--sidebar-bg); color: var(--sidebar-text); height: 100vh; position: fixed; display: flex; flex-direction: column; box-shadow: 2px 0 10px rgba(0,0,0,0.1); }
.sidebar-header { padding: 25px; text-align: center; border-bottom: 1px solid #2c3e50; }
.sidebar-logo { color: var(--white); font-size: 1.4em; font-weight: bold; }
.sidebar-logo span { color: var(--primary); }
.nav-links { padding: 20px 0; flex-grow: 1; }
.nav-item { display: flex; align-items: center; padding: 12px 25px; color: var(--sidebar-text); font-size: 0.95em; border-left: 4px solid transparent; }
.nav-item:hover { background: rgba(255,255,255,0.05); color: var(--white); }
.nav-item.active { background: #2c3e50; color: var(--white); border-left-color: var(--primary); font-weight: bold; }

/* Layout & Cards */
.main { margin-left: 240px; padding: 30px; width: calc(100% - 240px); box-sizing: border-box; }
.card { background: var(--white); padding: 25px; border-radius: 10px; box-shadow: 0 2px 5px rgba(0,0,0,0.05); margin-bottom: 25px; }

/* Tables */
table { width: 100%; border-collapse: collapse; background: var(--white); border-radius: 8px; overflow: hidden; }
th { text-align: left; padding: 15px; color: var(--text-light); font-size: 0.8em; text-transform: uppercase; border-bottom: 1px solid var(--border-color); }
td { padding: 15px; border-bottom: 1px solid var(--border-color); }

/* Buttons & Badges */
.btn { padding: 10px 20px; border: none; border-radius: 6px; cursor: pointer; font-weight: bold; display: inline-flex; align-items: center; gap: 8px; }
.btn-primary { background: var(--primary); color: white; }
.status-badge { padding: 5px 12px; border-radius: 20px; font-size: 0.8em; font-weight: bold; }