:root, [data-theme="dark"] {
    --bg-base: #0b0f19;
    --bg-surface: #111827;
    --bg-card: #1f2937;
    --bg-card-hover: #283548;
    --border-color: #374151;
    --text-main: #f9fafb;
    --text-muted: #9ca3af;
    --text-dim: #6b7280;
    --accent-primary: #0284c7;
    --accent-primary-hover: #0369a1;
    --accent-success: #10b981;
    --accent-warning: #f59e0b;
    --accent-danger: #ef4444;
    --accent-info: #38bdf8;
    --code-bg: #030712;
    --sidebar-width: 260px;
    --header-height: 64px;
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.3), 0 2px 4px -1px rgba(0,0,0,0.2);
}

[data-theme="light"] {
    --bg-base: #f3f4f6;
    --bg-surface: #ffffff;
    --bg-card: #ffffff;
    --bg-card-hover: #f9fafb;
    --border-color: #e5e7eb;
    --text-main: #111827;
    --text-muted: #4b5563;
    --text-dim: #9ca3af;
    --accent-primary: #0284c7;
    --accent-primary-hover: #0369a1;
    --accent-success: #059669;
    --accent-warning: #d97706;
    --accent-danger: #dc2626;
    --accent-info: #0284c7;
    --code-bg: #1f2937;
    --shadow: 0 1px 3px 0 rgba(0,0,0,0.1), 0 1px 2px 0 rgba(0,0,0,0.06);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-base);
    color: var(--text-main);
    line-height: 1.5;
    font-size: 14px;
}

a {
    color: var(--accent-info);
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}

/* App Wrapper & Layout */
.app-wrapper {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.top-header {
    height: var(--header-height);
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1.5rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-left, .header-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.header-brand {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
}

.brand-badge {
    background: linear-gradient(135deg, #0284c7, #06b6d4);
    color: #fff;
    font-weight: 800;
    font-size: 1.1rem;
    letter-spacing: 1px;
    padding: 2px 8px;
    border-radius: var(--radius-sm);
}

.brand-sub {
    color: var(--text-muted);
    font-size: 0.85rem;
    font-weight: 500;
}

.system-status-indicator {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin: 0 0.5rem;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    display: inline-block;
}
.status-dot.status-online { background-color: var(--accent-success); box-shadow: 0 0 6px var(--accent-success); }
.status-dot.status-delayed { background-color: var(--accent-warning); }
.status-dot.status-offline { background-color: var(--accent-danger); }

.user-profile {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    border-left: 1px solid var(--border-color);
    padding-left: 1rem;
}

.user-name {
    font-weight: 600;
}

.user-role-tag {
    background-color: rgba(2, 132, 199, 0.2);
    color: var(--accent-info);
    font-size: 0.7rem;
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-weight: 700;
}

.btn-icon {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 6px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
}
.btn-icon:hover {
    color: var(--text-main);
    background-color: var(--bg-card);
}

.btn-logout {
    color: var(--accent-danger);
    display: flex;
    align-items: center;
    padding: 4px;
}

.app-body {
    display: flex;
    flex: 1;
}

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-surface);
    border-right: 1px solid var(--border-color);
    flex-shrink: 0;
}

.sidebar-nav {
    padding: 1rem 0;
}

.nav-section-title {
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-dim);
    padding: 0.75rem 1.25rem 0.25rem;
    font-weight: 700;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.5rem 1.25rem;
    color: var(--text-muted);
    font-weight: 500;
    transition: all 0.15s ease;
}
.nav-item:hover {
    color: var(--text-main);
    background-color: var(--bg-card-hover);
    text-decoration: none;
}
.nav-item.active {
    color: #fff;
    background-color: rgba(2, 132, 199, 0.2);
    border-left: 3px solid var(--accent-primary);
}

.nav-icon {
    display: flex;
    align-items: center;
}

.main-content {
    flex: 1;
    padding: 1.75rem;
    overflow-x: hidden;
}

.app-footer {
    background-color: var(--bg-surface);
    border-top: 1px solid var(--border-color);
    padding: 0.75rem 1.5rem;
    font-size: 0.75rem;
    color: var(--text-dim);
    display: flex;
    justify-content: space-between;
}

/* Typography & Headings */
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.page-title {
    font-size: 1.5rem;
    font-weight: 700;
}

.page-subtitle {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-top: 2px;
}

.section-subtitle {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-muted);
}

/* Cards & Layout Grids */
.card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.card-header {
    padding: 1rem 1.25rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-title {
    font-size: 1.05rem;
    font-weight: 600;
}

.card-body {
    padding: 1.25rem;
}

.grid-2-col {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.25rem;
}

.grid-3-col {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.25rem;
}

.grid-4-col {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.25rem;
}

@media (max-width: 1024px) {
    .grid-2-col, .grid-3-col, .grid-4-col {
        grid-template-columns: 1fr;
    }
}

/* KPI Cards */
.kpi-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.25rem;
    margin-bottom: 1.5rem;
}

.kpi-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    box-shadow: var(--shadow);
}

.kpi-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}
.kpi-devices { background-color: rgba(2, 132, 199, 0.15); color: var(--accent-info); }
.kpi-mqtt { background-color: rgba(16, 185, 129, 0.15); color: var(--accent-success); }
.kpi-inverters { background-color: rgba(245, 158, 11, 0.15); color: var(--accent-warning); }
.kpi-api { background-color: rgba(139, 92, 246, 0.15); color: #a78bfa; }

.kpi-value {
    font-size: 1.75rem;
    font-weight: 800;
    line-height: 1.2;
}

.kpi-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 500;
}

.kpi-subtext {
    font-size: 0.75rem;
    color: var(--text-dim);
    margin-top: 4px;
}

/* Stats List */
.stats-list {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.stat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px dashed var(--border-color);
    padding-bottom: 0.4rem;
}

.stat-name {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.stat-val {
    font-weight: 600;
}

/* Metrics Row */
.metric-box {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.75rem;
    text-align: center;
}
.metric-label { font-size: 0.75rem; color: var(--text-muted); }
.metric-value { font-size: 1.3rem; font-weight: 700; margin-top: 4px; }

/* Register Grid */
.register-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 0.75rem;
}
.register-item {
    background: var(--code-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.5rem 0.75rem;
}
.reg-name {
    display: block;
    color: var(--accent-info);
    font-size: 0.75rem;
    margin-bottom: 2px;
}
.reg-val {
    margin: 0;
    white-space: pre-wrap;
    word-break: break-all;
    color: var(--text-main);
}

/* Tables */
.table-responsive {
    overflow-x: auto;
}

.table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
}

.table th {
    background-color: var(--bg-surface);
    color: var(--text-muted);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 0.65rem 1rem;
    border-bottom: 1px solid var(--border-color);
    font-weight: 600;
}

.table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-color);
    vertical-align: middle;
}

.table tr:last-child td {
    border-bottom: none;
}

.table tbody tr:hover {
    background-color: var(--bg-card-hover);
}

/* Forms & Controls */
.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 0.35rem;
    color: var(--text-muted);
}

.form-control {
    width: 100%;
    padding: 0.6rem 0.75rem;
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-size: 0.85rem;
    outline: none;
}
.form-control:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.2);
}

.form-control-sm {
    padding: 0.35rem 0.5rem;
    font-size: 0.75rem;
}

.form-hint {
    display: block;
    font-size: 0.7rem;
    color: var(--text-dim);
    margin-top: 3px;
}

.checkbox-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    padding: 0.75rem;
    border-radius: var(--radius-sm);
}
.checkbox-grid label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8rem;
    color: var(--text-main);
    margin: 0;
    cursor: pointer;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.15s ease;
}
.btn-primary { background-color: var(--accent-primary); color: #fff; }
.btn-primary:hover { background-color: var(--accent-primary-hover); text-decoration: none; }
.btn-outline { background: transparent; border-color: var(--border-color); color: var(--text-main); }
.btn-outline:hover { background-color: var(--bg-surface); text-decoration: none; }
.btn-warning { background-color: var(--accent-warning); color: #000; }
.btn-danger { background-color: var(--accent-danger); color: #fff; }
.btn-success { background-color: var(--accent-success); color: #fff; }

.btn-sm { padding: 0.25rem 0.6rem; font-size: 0.75rem; }
.btn-xs { padding: 0.2rem 0.45rem; font-size: 0.7rem; }
.btn-lg { padding: 0.75rem 1.25rem; font-size: 1rem; }
.btn-block { width: 100%; }

.btn-group {
    display: inline-flex;
    gap: 4px;
}

/* Badges & Tags */
.badge {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 999px;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.3px;
}
.badge-success { background-color: rgba(16, 185, 129, 0.2); color: var(--accent-success); }
.badge-warning { background-color: rgba(245, 158, 11, 0.2); color: var(--accent-warning); }
.badge-danger { background-color: rgba(239, 68, 68, 0.2); color: var(--accent-danger); }
.badge-info { background-color: rgba(56, 189, 248, 0.2); color: var(--accent-info); }
.badge-secondary { background-color: rgba(107, 114, 128, 0.2); color: var(--text-muted); }

.tag {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-family: monospace;
}

/* Pills Bar */
.pill-bar {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}
.pill {
    padding: 0.35rem 0.75rem;
    border-radius: 999px;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.75rem;
    font-weight: 600;
}
.pill:hover { text-decoration: none; color: var(--text-main); }
.pill.active { background: var(--accent-primary); border-color: var(--accent-primary); color: #fff; }

/* Alerts */
.alert {
    padding: 0.75rem 1rem;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    margin-bottom: 1rem;
}
.alert-danger { background-color: rgba(239, 68, 68, 0.15); border: 1px solid var(--accent-danger); color: #fca5a5; }
.alert-warning { background-color: rgba(245, 158, 11, 0.15); border: 1px solid var(--accent-warning); color: #fcd34d; }
.alert-success { background-color: rgba(16, 185, 129, 0.15); border: 1px solid var(--accent-success); color: #6ee7b7; }
.alert-info { background-color: rgba(56, 189, 248, 0.15); border: 1px solid var(--accent-info); color: #7dd3fc; }

/* Terminal & Console Boxes */
.terminal-box {
    background: var(--code-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.75rem;
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-size: 0.8rem;
    color: #e5e7eb;
    height: 380px;
    overflow-y: auto;
}
.term-line {
    margin-bottom: 4px;
    word-break: break-all;
}

/* Modals */
.raw-packet-modal {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.7);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
}
.raw-packet-modal .modal-content {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    width: 90%;
    max-width: 700px;
    box-shadow: var(--shadow);
    padding: 1.5rem;
}
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}
.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-muted);
    cursor: pointer;
}

/* Login Page Styling */
.login-body {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
}
.login-container {
    width: 100%;
    max-width: 420px;
    padding: 1.5rem;
}
.login-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2.25rem;
    box-shadow: 0 10px 25px -5px rgba(0,0,0,0.5);
}
.login-brand {
    text-align: center;
    margin-bottom: 1.75rem;
}
.brand-logo-circle {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, #0284c7, #06b6d4);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 0.75rem;
}
.login-brand h1 {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: 1.5px;
}
.login-brand .subtitle {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 2px;
}
.login-footer {
    text-align: center;
    margin-top: 1.5rem;
    font-size: 0.75rem;
    color: var(--text-dim);
}
.secure-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    margin-top: 4px;
    color: var(--accent-success);
    font-weight: 600;
}

/* Helpers */
.font-mono { font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace; }
.font-bold { font-weight: 700; }
.text-success { color: var(--accent-success); }
.text-warning { color: var(--accent-warning); }
.text-danger { color: var(--accent-danger); }
.text-info { color: var(--accent-info); }
.text-muted { color: var(--text-muted); }
.text-center { text-align: center; }
.text-sm { font-size: 0.8rem; }
.text-xs { font-size: 0.7rem; }
.mt-3 { margin-top: 0.75rem; }
.mt-4 { margin-top: 1.5rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-4 { margin-bottom: 1.5rem; }
.p-0 { padding: 0 !important; }
.p-3 { padding: 0.75rem !important; }
.p-4 { padding: 1.25rem !important; }