:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --shadow: 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);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

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

/* Sidebar */
.sidebar {
    width: 260px;
    background-color: var(--bg-card);
    border-right: 1px solid var(--border);
    padding: 2rem 1.5rem;
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
    margin-bottom: 2.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-links {
    list-style: none;
}

.nav-item {
    margin-bottom: 0.5rem;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    text-decoration: none;
    color: var(--text-muted);
    border-radius: 0.5rem;
    transition: all 0.2s;
    font-weight: 500;
}

.nav-link:hover, .nav-link.active {
    background-color: #eff6ff;
    color: var(--primary);
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: 260px;
    padding: 2.5rem;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2.5rem;
}

.welcome-msg h1 {
    font-size: 1.875rem;
    font-weight: 700;
}

.welcome-msg p {
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* Dashboard Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2.5rem;
}

.stat-card {
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    margin-top: 0.5rem;
}

/* Tables / Recent Activity */
.section-card {
    background: var(--bg-card);
    border-radius: 1rem;
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
    padding: 1.5rem;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.btn-primary {
    background-color: var(--primary);
    color: white;
    padding: 0.625rem 1.25rem;
    border-radius: 0.5rem;
    border: none;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
}

table {
    width: 100%;
    border-collapse: collapse;
}

th {
    text-align: left;
    padding: 1rem;
    color: var(--text-muted);
    font-weight: 600;
    border-bottom: 1px solid var(--border);
}

.status-badge {
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
}

.status-badge.draft { background: #f1f5f9; color: #475569; }
.status-badge.sent { background: #fff7ed; color: #c2410c; }
.status-badge.accepted { background: #f0fdf4; color: #15803d; }
.status-badge.rejected { background: #fef2f2; color: #b91c1c; }
.status-badge.near-expiry { background: #fffbeb; color: #9a3412; border: 1px solid #fed7aa; }

td {
    padding: 1rem;
    border-bottom: 1px solid var(--border);
}

/* Modals */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.4);
    backdrop-filter: blur(4px);
}

.modal-content {
    background-color: var(--bg-card);
    margin: 2% auto;
    padding: 2rem;
    border-radius: 1rem;
    width: 500px;
    max-height: 95vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.close {
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    color: var(--text-muted);
}

/* Forms */
.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.form-group input, .form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    font-size: 1rem;
    transition: border-color 0.2s;
    background-color: white;
}

.form-group input:focus, .form-group select:focus {
    outline: none;
    border-color: var(--primary);
}