:root {
    --primary: #2563eb;
    --primary-light: #eff6ff;
    --sidebar-w: 240px;
    --border: #e5e7eb;
    --bg: #f3f4f6;
    --panel: #ffffff;
    --text: #111827;
    --muted: #6b7280;
}

* { box-sizing: border-box; }

body {
    font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    margin: 0;
}

/* Shell */
.app-shell { display: flex; min-height: 100vh; }

.app-sidebar {
    width: var(--sidebar-w);
    background: var(--panel);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0; left: 0;
    height: 100vh;
    z-index: 200;
    transition: transform 0.25s;
}

.sidebar-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1.25rem 1rem;
    border-bottom: 1px solid var(--border);
}

.sidebar-brand i { font-size: 1.5rem; color: var(--primary); }
.sidebar-brand strong { display: block; font-size: 0.95rem; }
.sidebar-brand small { color: var(--muted); font-size: 0.75rem; }

.sidebar-menu { flex: 1; padding: 0.75rem 0.5rem; }

.menu-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--muted);
    padding: 0.75rem 0.75rem 0.25rem;
    font-weight: 600;
}

.menu-item {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.6rem 0.75rem;
    border-radius: 8px;
    color: var(--muted);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 2px;
    transition: all 0.15s;
}

.menu-item:hover { background: var(--bg); color: var(--text); }
.menu-item.active { background: var(--primary-light); color: var(--primary); font-weight: 600; }
.menu-item i { font-size: 1.1rem; width: 22px; }

.sidebar-footer { padding: 0.5rem; border-top: 1px solid var(--border); }

.app-main {
    flex: 1;
    margin-left: var(--sidebar-w);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.app-topbar {
    background: var(--panel);
    border-bottom: 1px solid var(--border);
    padding: 0.75rem 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

.topbar-title { font-size: 1.15rem; font-weight: 700; margin: 0; flex: 1; }

.topbar-actions { display: flex; align-items: center; gap: 0.75rem; }

.user-pill {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--muted);
}

.user-avatar {
    width: 32px; height: 32px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.85rem;
}

.app-content { padding: 1.5rem; flex: 1; max-width: 1200px; width: 100%; }

.sidebar-backdrop {
    position: fixed; inset: 0;
    background: rgba(0,0,0,0.4);
    z-index: 150;
    display: none;
}
.sidebar-backdrop.show { display: block; }

/* Stats */
.stat-box {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1rem 1.15rem;
    height: 100%;
    border-left: 4px solid var(--primary);
}

.stat-box.stat-blue { border-left-color: #2563eb; }
.stat-box.stat-green { border-left-color: #059669; }
.stat-box.stat-purple { border-left-color: #7c3aed; }
.stat-box.stat-orange { border-left-color: #d97706; }

.stat-label { display: block; font-size: 0.8rem; color: var(--muted); margin-bottom: 0.25rem; }
.stat-value { display: block; font-size: 1.35rem; font-weight: 700; }
.stat-unit { font-size: 0.85rem; font-weight: 500; color: var(--muted); }

.mini-stat span { display: block; font-size: 0.75rem; color: var(--muted); }
.mini-stat strong { font-size: 1rem; }

/* Panels */
.panel {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 12px;
    overflow: hidden;
}

.panel-head {
    padding: 0.85rem 1.15rem;
    border-bottom: 1px solid var(--border);
    font-weight: 600;
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.5rem;
}

.panel-head i { color: var(--primary); margin-right: 0.35rem; }
.panel-body { padding: 1rem 1.15rem; }

/* Month toolbar */
.month-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.month-nav { display: flex; align-items: center; gap: 0.5rem; }
.month-title { font-size: 1.2rem; font-weight: 700; min-width: 160px; text-align: center; }

/* Partner cards */
.partner-card {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 0.85rem;
    text-decoration: none;
    color: var(--text);
    height: 100%;
    transition: all 0.15s;
}

.partner-card:hover { border-color: var(--primary); box-shadow: 0 2px 8px rgba(37,99,235,0.1); color: var(--text); }
.partner-card.active { border-color: var(--primary); background: var(--primary-light); }

.partner-avatar {
    width: 40px; height: 40px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.partner-name { display: block; font-weight: 600; font-size: 0.9rem; }
.partner-amount { display: block; font-weight: 700; color: var(--primary); font-size: 1.05rem; }
.partner-meta { display: block; font-size: 0.75rem; color: var(--muted); }

/* Tables */
.expense-table thead th {
    background: var(--bg);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--muted);
    font-weight: 600;
    padding: 0.65rem 1rem;
    border-bottom: 1px solid var(--border);
}

.expense-table tbody td {
    padding: 0.75rem 1rem;
    vertical-align: middle;
    border-bottom: 1px solid #f3f4f6;
}

.expense-table tfoot td {
    padding: 0.75rem 1rem;
    background: var(--bg);
    border-top: 2px solid var(--border);
}

.amount-cell { font-weight: 600; white-space: nowrap; }

.person-tag {
    display: inline-flex;
    width: 26px; height: 26px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 6px;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 700;
    margin-right: 0.35rem;
}

/* Forms */
.simple-form {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    max-width: 520px;
}

.page-heading { font-size: 1.2rem; font-weight: 700; margin-bottom: 1.25rem; }

.admin-table-wrap {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 12px;
    overflow: hidden;
}
.admin-table { margin: 0; }
.admin-table th { background: var(--bg); }

/* Login */
.login-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #eff6ff 0%, #f3f4f6 100%);
}

.login-box {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 2.5rem;
    width: 100%;
    max-width: 400px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.06);
}

.login-box h1 { font-size: 1.5rem; font-weight: 700; }

.loading-overlay {
    position: fixed; inset: 0;
    background: rgba(255,255,255,0.85);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

[data-bs-theme="dark"] {
    --bg: #111827;
    --panel: #1f2937;
    --border: #374151;
    --text: #f9fafb;
    --muted: #9ca3af;
    --primary-light: rgba(37,99,235,0.15);
}

[data-bs-theme="dark"] .loading-overlay { background: rgba(0,0,0,0.7); }

/* Mobile */
@media (max-width: 991px) {
    .app-sidebar { transform: translateX(-100%); }
    .app-sidebar.show { transform: translateX(0); }
    .app-main { margin-left: 0; }
}

@media (max-width: 576px) {
    .app-content { padding: 1rem; }
    .stat-value { font-size: 1.15rem; }
}