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

:root {
    --primary-color: #25D366;
    --secondary-color: #128C7E;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    --dark-color: #1f2937;
    --light-color: #f3f4f6;
    --border-color: #e5e7eb;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --sidebar-width: 260px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--light-color);
    color: var(--text-primary);
}

/* Screen Management */
.screen {
    display: none;
}

.screen.active {
    display: block;
}

/* Login Screen */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--secondary-color) 0%, var(--primary-color) 100%);
}

.login-box {
    background: white;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    width: 100%;
    max-width: 400px;
}

.logo {
    text-align: center;
    margin-bottom: 30px;
}

.logo i {
    font-size: 64px;
    color: var(--primary-color);
}

.logo h1 {
    margin-top: 10px;
    color: var(--dark-color);
}

.form-group {
    position: relative;
    margin-bottom: 20px;
}

.form-group input {
    width: 100%;
    padding: 12px 40px 12px 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    transition: border-color 0.3s;
}

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

.form-group i {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
}

.btn-primary {
    width: 100%;
    padding: 12px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s;
}

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

.error-message {
    color: var(--danger-color);
    margin-top: 10px;
    text-align: center;
    font-size: 14px;
}

/* Dashboard Layout */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background: var(--dark-color);
    color: white;
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    padding: 20px;
    background: var(--secondary-color);
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
}

.sidebar-header i {
    font-size: 28px;
}

.sidebar-nav {
    flex: 1;
    overflow-y: auto;
    padding: 20px 0;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 20px;
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: all 0.3s;
    cursor: pointer;
}

.nav-item:hover {
    background: rgba(255, 255, 255, 0.1);
    color: white;
}

.nav-item.active {
    background: var(--primary-color);
    color: white;
    border-left: 4px solid white;
}

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

.sidebar-footer {
    padding: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.user-info {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 15px;
    color: rgba(255, 255, 255, 0.8);
}

.user-info i {
    font-size: 24px;
}

.btn-logout {
    width: 100%;
    padding: 10px;
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-logout:hover {
    background: var(--danger-color);
    border-color: var(--danger-color);
}

/* Main Content */
.main-content {
    margin-left: var(--sidebar-width);
    min-height: 100vh;
}

.topbar {
    background: white;
    padding: 20px 30px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.topbar h2 {
    font-size: 24px;
    color: var(--dark-color);
}

.btn-icon {
    padding: 10px;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s;
}

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

.content-area {
    padding: 30px;
}

.page {
    display: none;
}

.page.active {
    display: block;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    display: flex;
    align-items: center;
    gap: 20px;
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    color: white;
}

.stat-icon.blue {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.stat-icon.green {
    background: linear-gradient(135deg, #25D366 0%, #128C7E 100%);
}

.stat-icon.purple {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

.stat-icon.orange {
    background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
}

.stat-value {
    font-size: 32px;
    font-weight: 700;
    color: var(--dark-color);
}

.stat-label {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 5px;
}

/* Card */
.card {
    background: white;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
}

.card-header {
    padding: 20px 25px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-header h3 {
    font-size: 18px;
    color: var(--dark-color);
}

.card-header > div {
    display: flex;
    gap: 10px;
    align-items: center;
}

.card-header select {
    padding: 8px 12px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 14px;
}

.card-body {
    padding: 25px;
}

/* Quick Actions */
.quick-actions {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
}

.quick-action-btn {
    padding: 20px;
    background: var(--light-color);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.quick-action-btn:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 211, 102, 0.3);
}

.quick-action-btn i {
    font-size: 32px;
}

/* Form Elements */
.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="password"],
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    font-family: inherit;
    transition: border-color 0.3s;
}

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

.form-group small {
    display: block;
    margin-top: 5px;
    color: var(--text-secondary);
    font-size: 12px;
}

/* Sessions List */
.session-item {
    background: var(--light-color);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.session-info h4 {
    margin-bottom: 5px;
}

.session-status {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 600;
}

.session-status.connected {
    background: #d4edda;
    color: #155724;
}

.session-status.disconnected {
    background: #f8d7da;
    color: #721c24;
}

.session-status.qr {
    background: #fff3cd;
    color: #856404;
}

.session-actions {
    display: flex;
    gap: 10px;
}

.btn-sm {
    padding: 8px 16px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 13px;
    transition: all 0.3s;
}

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

.btn-danger {
    background: var(--danger-color);
    color: white;
}

.btn-sm:hover {
    opacity: 0.8;
    transform: translateY(-1px);
}

/* Upload Area */
.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    padding: 40px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: var(--light-color);
}

.upload-area input[type="file"] {
    display: none;
}

.upload-placeholder i {
    font-size: 48px;
    color: var(--text-secondary);
    margin-bottom: 10px;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: white;
    border-radius: 12px;
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-body {
    padding: 20px;
}

.close {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-secondary);
    cursor: pointer;
    background: none;
    border: none;
}

.close:hover {
    color: var(--danger-color);
}

/* Table */
table {
    width: 100%;
    border-collapse: collapse;
}

thead {
    background: var(--light-color);
}

th, td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    font-weight: 600;
    color: var(--text-primary);
}

/* Loading */
.loading {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

/* API Docs */
.api-docs {
    margin-top: 30px;
    padding: 20px;
    background: var(--dark-color);
    color: white;
    border-radius: 8px;
}

.api-docs pre {
    margin-top: 15px;
    overflow-x: auto;
}

.api-docs code {
    font-family: 'Courier New', monospace;
    font-size: 13px;
}

/* Pagination Styles */
.pagination-container {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    margin-top: 20px;
    padding: 15px;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    border-radius: 12px;
    flex-wrap: wrap;
}

.pagination-btn {
    padding: 10px 16px;
    border: none;
    border-radius: 8px;
    background: white;
    color: var(--text-primary);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 6px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.pagination-btn:hover:not(.disabled) {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(37, 211, 102, 0.3);
}

.pagination-btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    background: #e9ecef;
}

.pagination-info {
    padding: 10px 20px;
    background: white;
    border-radius: 8px;
    font-size: 14px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.pagination-info strong {
    color: var(--primary-color);
}

/* Row Highlights */
.row-sent {
    background-color: rgba(40, 167, 69, 0.05);
}

.row-failed {
    background-color: rgba(220, 53, 69, 0.05);
}

/* Checkbox Styles */
.queue-checkbox, #selectAllQueue {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--primary-color);
}

table th input[type="checkbox"],
table td input[type="checkbox"] {
    margin: 0;
    padding: 0;
}

/* Date Input Styles */
input[type="date"] {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 14px;
    background: white;
    cursor: pointer;
}

input[type="date"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(37, 211, 102, 0.2);
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s;
    }

    .sidebar.active {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }
}