:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #64748b;
    --bg: #f1f5f9;
    --white: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --danger: #ef4444;
    --success: #22c55e;
    --sidebar-width: 260px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--bg);
    color: var(--text);
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--white);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    height: 100vh;
}

.sidebar-header {
    padding: 24px;
    border-bottom: 1px solid var(--border);
    text-align: center;
}

.sidebar-header h2 {
    color: var(--primary);
    font-size: 1.25rem;
}

.nav-menu {
    padding: 20px 0;
    flex: 1;
}

.nav-item {
    padding: 12px 24px;
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--text-light);
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s;
}

.nav-item:hover, .nav-item.active {
    background: #f8fafc;
    color: var(--primary);
    border-right: 3px solid var(--primary);
}

.nav-item i {
    width: 20px;
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    height: 100vh;
}

.topbar {
    height: 64px;
    background: var(--white);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    flex-shrink: 0;
}

.content-area {
    padding: 24px;
    flex: 1;
    overflow-y: auto;
}

/* Common Elements */
.form-group { margin-bottom: 16px; }
.form-group label { display: block; margin-bottom: 6px; font-weight: 500; font-size: 0.9rem; }
.form-control { width: 100%; padding: 10px 12px; border: 1px solid var(--border); border-radius: 6px; font-size: 1rem; outline: none; transition: border 0.2s; }
.form-control:focus { border-color: var(--primary); }

.btn { padding: 10px 16px; border: none; border-radius: 6px; font-weight: 600; cursor: pointer; display: inline-flex; align-items: center; gap: 8px; font-size: 0.9rem; transition: background 0.2s; }
.btn-primary { background: var(--primary); color: var(--white); }
.btn-primary:hover { background: var(--primary-dark); }
.btn-secondary { background: var(--bg); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover { background: #e2e8f0; }
.btn-danger { background: var(--danger); color: var(--white); }

.card { background: var(--white); border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.1); padding: 24px; margin-bottom: 24px; }
.card-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; border-bottom: 1px solid var(--border); padding-bottom: 16px; }
.card-title { font-size: 1.1rem; font-weight: 600; }

/* Grid */
.grid { display: grid; gap: 20px; }
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }

.project-card { border: 1px solid var(--border); border-radius: 8px; padding: 16px; transition: transform 0.2s, box-shadow 0.2s; background: var(--bg); }
.project-card:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,0.05); }
.project-title { font-size: 1.1rem; font-weight: bold; margin-bottom: 8px; color: var(--primary); }
.project-meta { font-size: 0.85rem; color: var(--text-light); margin-bottom: 16px; }

/* Alert */
#alert-box { position: fixed; top: 20px; right: 20px; padding: 12px 24px; border-radius: 6px; color: white; font-weight: bold; z-index: 2000; display: none; box-shadow: 0 4px 6px rgba(0,0,0,0.1); }
.alert-error { background: var(--danger); }
.alert-success { background: var(--success); }

/* Auth Form */
.auth-wrapper { width: 100%; height: 100vh; display: flex; align-items: center; justify-content: center; background: linear-gradient(135deg, #1e3a8a 0%, #3b82f6 100%); }
.auth-card { background: var(--white); padding: 40px; border-radius: 12px; box-shadow: 0 10px 25px rgba(0,0,0,0.1); width: 100%; max-width: 400px; }
.auth-card h2 { text-align: center; margin-bottom: 24px; color: var(--primary); }
.auth-tabs { display: flex; margin-bottom: 20px; border-bottom: 2px solid var(--border); }
.auth-tab { flex: 1; text-align: center; padding: 10px; cursor: pointer; font-weight: 600; color: var(--text-light); }
.auth-tab.active { color: var(--primary); border-bottom: 2px solid var(--primary); margin-bottom: -2px; }