:root {
    /* Color Palette */
    --bg-main: #f1f5f9;
    --bg-card: #ffffff;
    --bg-sidebar: #0f172a;
    
    --text-main: #334155;
    --text-muted: #64748b;
    --text-light: #f8fafc;
    
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --success: #10b981;
    --danger: #ef4444;
    --warn: #f59e0b;
    --purple: #8b5cf6;
    
    --border: #e2e8f0;
    --border-color: #e2e8f0;
    --radius: 12px;
    --shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
    --shadow-hover: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Mode Variables */
body.dark-mode {
    --bg-main: #0f172a;
    --bg-card: #1e293b;
    --bg-sidebar: #020617;
    
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --text-light: #f8fafc;
    
    --border: #334155;
    --border-color: #334155;
    --shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.4);
    --shadow-hover: 0 10px 25px -5px rgba(0, 0, 0, 0.6);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    line-height: 1.5;
}

/* Utilities */
.accent-text { color: var(--accent); }
.text-success { color: var(--success); }
.text-purple { color: var(--purple); }
.mt-15 { margin-top: 15px; }

/* Loader */
.loader-overlay {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(255,255,255,0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}
.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}
@keyframes spin { 100% { transform: rotate(360deg); } }

/* Login Screen */
.login-screen {
    min-height: 100vh;
    padding: 20px;
    display: flex;
    align-items: flex-start; /* Ensures top is never cut off */
    justify-content: center;
    background: linear-gradient(135deg, var(--bg-sidebar) 0%, #1e293b 100%);
}
.login-card {
    background: var(--bg-card);
    padding: 40px;
    border-radius: var(--radius);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    width: 100%;
    max-width: 400px;
    margin: 40px auto; /* Push it down from the top slightly */
    animation: fadeIn 0.5s ease-out;
}
.login-header {
    text-align: center;
    margin-bottom: 30px;
}
.login-header .logo-icon {
    font-size: 48px;
    color: var(--accent);
    margin-bottom: 10px;
}
.login-header h2 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-main);
}
.login-header p {
    color: var(--text-muted);
    font-size: 14px;
    margin-top: 5px;
}
.input-group {
    margin-bottom: 20px;
}
.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    font-size: 14px;
}
.input-group input {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 16px;
    transition: var(--transition);
}
.input-group input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}
.btn {
    display: inline-block;
    padding: 12px 20px;
    border: none;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
}
.btn-primary {
    background: var(--accent);
    color: white;
    width: 100%;
}
.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}
.btn-dark {
    background: var(--bg-sidebar);
    color: white;
}
.btn-dark:hover {
    background: #1e293b;
}
.btn-full {
    width: 100%;
}
.btn-outline {
    background: transparent;
    border: 1px solid rgba(255,255,255,0.2);
    color: var(--text-light);
}
.btn-outline:hover {
    background: rgba(255,255,255,0.1);
}
.error-msg {
    color: var(--danger);
    background: rgba(239, 68, 68, 0.1);
    padding: 10px;
    border-radius: 8px;
    margin-top: 15px;
    font-size: 14px;
    text-align: center;
}

/* Dashboard Layout */
.dashboard-layout {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: 260px;
    background: var(--bg-sidebar);
    color: var(--text-light);
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow);
}
.sidebar-header {
    padding: 24px;
    display: flex;
    align-items: center;
    gap: 12px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}
.sidebar-header .logo-icon {
    font-size: 24px;
    color: var(--accent);
}
.sidebar-header h2 {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.5px;
}
.sidebar-nav {
    padding: 24px 16px;
    flex: 1;
    overflow-y: auto;
}
/* Scrollbar styling for sidebar */
.sidebar-nav::-webkit-scrollbar {
    width: 6px;
}
.sidebar-nav::-webkit-scrollbar-track {
    background: transparent; 
}
.sidebar-nav::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.1); 
    border-radius: 10px;
}
.sidebar-nav::-webkit-scrollbar-thumb:hover {
    background: rgba(255,255,255,0.2); 
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    color: #94a3b8;
    text-decoration: none;
    border-radius: 8px;
    margin-bottom: 8px;
    transition: var(--transition);
    font-weight: 500;
}
.nav-item:hover, .nav-item.active {
    background: rgba(255,255,255,0.1);
    color: white;
}
.nav-item.active {
    color: var(--accent);
    background: rgba(59, 130, 246, 0.1);
}
.sidebar-footer {
    padding: 24px 16px;
    border-top: 1px solid rgba(255,255,255,0.1);
}

/* Main Content */
.main-content {
    flex: 1;
    overflow-y: auto;
    padding: 30px 40px;
}
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}
.page-header h1 {
    font-size: 28px;
    font-weight: 700;
}

.error-banner {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger);
    padding: 15px;
    border-radius: var(--radius);
    margin-bottom: 20px;
    border: 1px solid rgba(239, 68, 68, 0.2);
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
    margin-bottom: 30px;
}
.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}
.stat-card {
    background: var(--bg-card);
    padding: 24px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    position: relative;
    overflow: hidden;
    transition: var(--transition);
}
.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}
.border-top-accent { border-top: 4px solid var(--accent); }
.border-top-success { border-top: 4px solid var(--success); }
.border-top-danger { border-top: 4px solid var(--danger); }
.border-top-warning { border-top: 4px solid #f59e0b; }

.stat-title {
    color: var(--text-muted);
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}
.stat-val {
    font-size: 32px;
    font-weight: 700;
}
.val-text { color: var(--text-main); }
.val-success { color: var(--success); }
.val-accent { color: var(--accent); }

.stat-icon {
    position: absolute;
    right: 24px;
    top: 24px;
    width: 48px;
    height: 48px;
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 20px;
}
.icon-accent { background: rgba(59, 130, 246, 0.1); color: var(--accent); }
.icon-success { background: rgba(16, 185, 129, 0.1); color: var(--success); }
.icon-danger { background: rgba(239, 68, 68, 0.1); color: var(--danger); }

.section-title {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

/* Chart & Devices Layout */
.responsive-grid-2-1 {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 24px;
}
.card {
    background: var(--bg-card);
    padding: 24px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.chart-container {
    position: relative;
    height: 250px;
    width: 100%;
}

/* Devices List */
.device-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
}
.device-item:last-child {
    border-bottom: none;
}
.device-info {
    display: flex;
    flex-direction: column;
}
.device-name {
    font-weight: 600;
    font-size: 14px;
}
.device-meta {
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 2px;
}
.device-status {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}
.status-ACTIVE { background: var(--success); box-shadow: 0 0 8px var(--success); }
.status-INACTIVE { background: var(--warn); }
.no-devices {
    text-align: center;
    padding: 20px;
    color: var(--text-muted);
}
.no-devices i {
    font-size: 24px;
    opacity: 0.5;
    margin-bottom: 10px;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Responsive Sidebar & Mobile Layout */
.mobile-header {
    display: none;
    justify-content: space-between;
    align-items: center;
    padding: 14px 20px;
    background: var(--bg-card);
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    margin: -30px -40px 30px -40px; /* Offset main-content padding */
    position: sticky;
    top: 0;
    z-index: 50;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}
.mobile-header-left {
    display: flex;
    align-items: center;
    gap: 15px;
}
.btn-icon {
    background: transparent;
    border: none;
    font-size: 18px;
    color: var(--text-main);
    cursor: pointer;
    padding: 6px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    transition: background 0.15s;
}
.btn-icon:hover { background: rgba(125,125,125,0.1); }

.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0, 0, 0, 0.65);
    z-index: 90;
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    opacity: 0;
    transition: opacity 0.3s ease;
}
.sidebar-overlay.show {
    display: block;
    opacity: 1;
}

/* Mobile Bottom Navigation */
.mobile-bottom-nav {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: rgba(15, 23, 42, 0.96);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding: 6px 8px 10px;
    z-index: 99;
    justify-content: space-around;
    align-items: center;
}
body:not(.dark-mode) .mobile-bottom-nav {
    background: rgba(255, 255, 255, 0.96);
    border-top: 1px solid #e2e8f0;
    box-shadow: 0 -4px 15px rgba(0,0,0,0.05);
}
.bottom-nav-link {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 3px;
    text-decoration: none;
    color: var(--text-muted);
    font-size: 10px;
    font-weight: 600;
    padding: 6px 10px;
    border-radius: 8px;
    transition: all 0.15s ease;
    background: none;
    border: none;
    cursor: pointer;
    font-family: inherit;
}
.bottom-nav-link i { font-size: 17px; }
.bottom-nav-link.active { color: var(--accent); }
.bottom-nav-link:active { transform: scale(0.92); }

@media (max-width: 1024px) {
    .responsive-grid-2-1 {
        grid-template-columns: 1fr;
    }
    
    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        height: 100vh;
        z-index: 100;
        transform: translateX(-100%);
        transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        box-shadow: 10px 0 30px rgba(0,0,0,0.4);
    }
    .sidebar.sidebar-open {
        transform: translateX(0);
    }
    .sidebar-close-btn {
        display: flex !important;
    }
    
    .main-content {
        padding: 20px 20px 85px 20px;
    }
    .mobile-header {
        display: flex;
        margin: -20px -20px 20px -20px;
    }
    .mobile-bottom-nav {
        display: flex;
    }
    .page-header h1 {
        font-size: 22px;
    }
}

@media (max-width: 768px) {
    .grid-3 { grid-template-columns: 1fr; }
    .stats-grid { grid-template-columns: 1fr; }
    
    .login-card {
        padding: 25px 20px;
    }
    .login-screen {
        padding: 20px 15px;
    }
}

/* ==========================================================================
   Quick SMS Composer & Sender ID Styles
   ========================================================================== */
.grid-express-sms {
    display: grid;
    grid-template-columns: 1.8fr 1fr;
    gap: 24px;
    margin-bottom: 24px;
}

@media (max-width: 1024px) {
    .grid-express-sms {
        grid-template-columns: 1fr;
    }
}

.sms-composer-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    gap: 18px;
    position: relative;
    overflow: hidden;
}

.sms-composer-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, #10b981, #06b6d4);
}

.sms-card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-bottom: 14px;
    border-bottom: 1px solid var(--border);
}

.sms-card-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 17px;
    font-weight: 700;
    color: var(--text-main);
}

.sms-card-title .icon-wrap {
    width: 34px;
    height: 34px;
    border-radius: 10px;
    background: rgba(16, 185, 129, 0.15);
    color: #10b981;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 15px;
}

.badge-pill {
    font-size: 11px;
    font-weight: 700;
    padding: 4px 10px;
    border-radius: 20px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-pill.emerald {
    background: rgba(16, 185, 129, 0.15);
    color: #10b981;
    border: 1px solid rgba(16, 185, 129, 0.3);
}

.badge-pill.amber {
    background: rgba(245, 158, 11, 0.15);
    color: #f59e0b;
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.sms-form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

@media (max-width: 640px) {
    .sms-form-grid {
        grid-template-columns: 1fr;
    }
}

.sms-form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.sms-form-label {
    font-size: 12px;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.4px;
}

.sms-input-wrap {
    position: relative;
    display: flex;
    align-items: center;
}

.sms-input-icon {
    position: absolute;
    left: 14px;
    color: var(--text-muted);
    font-size: 13px;
    pointer-events: none;
}

.sms-input, .sms-select, .sms-textarea {
    width: 100%;
    padding: 11px 14px;
    border-radius: 10px;
    background: var(--bg-main);
    border: 1px solid var(--border);
    color: var(--text-main);
    font-size: 14px;
    font-family: inherit;
    outline: none;
    transition: var(--transition);
}

.sms-input.with-icon {
    padding-left: 38px;
}

.sms-input:focus, .sms-select:focus, .sms-textarea:focus {
    border-color: #10b981;
    box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.15);
}

.sms-textarea {
    resize: vertical;
    min-height: 80px;
    line-height: 1.45;
}

.sms-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    padding-top: 10px;
}

.sender-id-selector-box {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--bg-main);
    padding: 6px 12px;
    border-radius: 10px;
    border: 1px solid var(--border);
    font-size: 12.5px;
    color: var(--text-muted);
}

.sender-id-badge {
    font-weight: 800;
    color: #10b981;
    letter-spacing: 0.5px;
}

.btn-send-sms {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 11px 22px;
    border-radius: 10px;
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: #ffffff;
    font-size: 14px;
    font-weight: 700;
    border: none;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3);
    transition: var(--transition);
}

.btn-send-sms:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(16, 185, 129, 0.4);
}

.btn-send-sms:active {
    transform: scale(0.97);
}

/* ROI Paper Calculator Card */
.roi-calculator-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 16px;
    position: relative;
    overflow: hidden;
}

.roi-calculator-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, #f59e0b, #eab308);
}

.roi-savings-box {
    background: var(--bg-main);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 16px;
    margin-top: 10px;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.roi-savings-amount {
    font-size: 28px;
    font-weight: 900;
    color: #10b981;
    line-height: 1.1;
}

.roi-savings-amount span {
    font-size: 14px;
    font-weight: 700;
    opacity: 0.85;
}

.roi-rolls-saved {
    font-size: 12px;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 6px;
}

/* Sender ID Management Component */
.sender-id-list-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 16px;
    background: var(--bg-main);
    border: 1px solid var(--border);
    border-radius: 10px;
    margin-bottom: 8px;
    transition: var(--transition);
}

.sender-id-list-item:hover {
    border-color: var(--accent);
}

.sender-id-tag {
    font-family: 'JetBrains Mono', monospace;
    font-weight: 700;
    font-size: 14px;
    letter-spacing: 0.5px;
    color: var(--text-main);
}