:root {
    --primary-color: #25D366;
    --primary-dark: #128C7E;
    --secondary-color: #34B7F1;
    --danger-color: #e74c3c;
    --warning-color: #f39c12;
    --success-color: #27ae60;
    --info-color: #3498db;
    --bg-color: #f5f6fa;
    --card-bg: #ffffff;
    --text-color: #2c3e50;
    --text-muted: #7f8c8d;
    --border-color: #e1e8ed;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 20px rgba(0, 0, 0, 0.15);
    --radius: 12px;
    --radius-sm: 8px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* Page visibility */
.page {
    min-height: 100vh;
}

.hidden {
    display: none !important;
}

/* Login Page */
.login-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
}

.login-header {
    text-align: center;
    color: white;
    margin-bottom: 30px;
}

.logo {
    font-size: 64px;
    margin-bottom: 10px;
}

.login-header h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
}

.login-header p {
    opacity: 0.9;
    font-size: 14px;
}

.login-form {
    background: var(--card-bg);
    padding: 40px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 400px;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    font-size: 14px;
    color: var(--text-color);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-family: inherit;
    transition: border-color 0.3s, box-shadow 0.3s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 211, 102, 0.1);
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    font-family: inherit;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--bg-color);
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

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

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

.btn-danger:hover {
    background: #c0392b;
}

.btn-block {
    width: 100%;
}

.btn-small {
    padding: 8px 16px;
    font-size: 12px;
}

/* Error message */
.error-message {
    background: #fee;
    color: var(--danger-color);
    padding: 12px;
    border-radius: var(--radius-sm);
    margin-top: 15px;
    font-size: 14px;
    text-align: center;
}

.error-box {
    background: #fee;
    color: var(--danger-color);
    padding: 16px;
    border-radius: var(--radius-sm);
    margin-bottom: 20px;
}

/* Dashboard Header */
.header {
    background: white;
    padding: 15px 30px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-small {
    font-size: 32px;
}

.header h1 {
    font-size: 20px;
    font-weight: 600;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 15px;
}

.user-display {
    font-size: 14px;
    color: var(--text-muted);
}

/* Tabs */
.tabs {
    display: flex;
    gap: 5px;
    padding: 20px 30px;
    background: white;
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
}

.tab {
    padding: 10px 20px;
    border: none;
    background: var(--bg-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s;
    font-family: inherit;
}

.tab:hover {
    background: var(--border-color);
}

.tab.active {
    background: var(--primary-color);
    color: white;
}

/* Content */
.content {
    padding: 30px;
    max-width: 1400px;
    margin: 0 auto;
}

.tab-content {
    animation: fadeIn 0.3s ease;
}

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

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

.status-card {
    background: white;
    padding: 25px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 20px;
}

.status-icon {
    font-size: 40px;
}

.status-info h3 {
    font-size: 14px;
    color: var(--text-muted);
    font-weight: 500;
    margin-bottom: 5px;
}

.status-info p {
    font-size: 18px;
    font-weight: 600;
}

/* Sessions Status */
.sessions-status h2 {
    margin-bottom: 20px;
    font-size: 18px;
}

.sessions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.session-card {
    background: white;
    padding: 25px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border-left: 4px solid var(--border-color);
}

.session-card.connected {
    border-left-color: var(--success-color);
}

.session-card.disconnected {
    border-left-color: var(--danger-color);
}

.session-card h3 {
    margin-bottom: 15px;
    font-size: 16px;
}

.session-status {
    font-size: 14px;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    display: inline-block;
    margin-bottom: 10px;
}

.session-details {
    font-size: 13px;
    color: var(--text-muted);
}

/* Sessions Management */
.sessions-management {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 30px;
}

.session-panel {
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.session-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.session-header h2 {
    font-size: 16px;
}

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

.qr-container {
    padding: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 350px;
}

.qr-placeholder {
    text-align: center;
    color: var(--text-muted);
}

.qr-container img {
    max-width: 280px;
    border-radius: var(--radius-sm);
}

.qr-connected {
    text-align: center;
    color: var(--success-color);
}

.qr-connected .icon {
    font-size: 64px;
    margin-bottom: 15px;
}

/* Groups */
.groups-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
}

.groups-header h2 {
    font-size: 18px;
}

.groups-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
}

.group-card {
    background: white;
    padding: 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: transform 0.3s, box-shadow 0.3s;
}

.group-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.group-card h3 {
    font-size: 16px;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.group-card .admin-badge {
    background: var(--primary-color);
    color: white;
    font-size: 10px;
    padding: 2px 8px;
    border-radius: 10px;
    font-weight: 500;
}

.group-card .group-info {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 15px;
}

.group-card .group-info p {
    margin-bottom: 5px;
}

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

.group-card .group-id {
    font-family: monospace;
    font-size: 11px;
    background: var(--bg-color);
    padding: 5px 10px;
    border-radius: var(--radius-sm);
    word-break: break-all;
}

/* Send Container */
.send-container {
    max-width: 700px;
    margin: 0 auto;
    background: white;
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.send-container h2 {
    margin-bottom: 25px;
    font-size: 20px;
}

.send-type-selector {
    display: flex;
    gap: 10px;
    margin-bottom: 25px;
}

.send-type {
    flex: 1;
    padding: 15px;
    border: 2px solid var(--border-color);
    background: white;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s;
    font-family: inherit;
}

.send-type:hover {
    border-color: var(--primary-color);
}

.send-type.active {
    border-color: var(--primary-color);
    background: rgba(37, 211, 102, 0.1);
}

#group-select-container {
    display: flex;
    gap: 10px;
    align-items: flex-end;
}

#group-select-container select {
    flex: 1;
}

.message-fields {
    transition: all 0.3s;
}

.result-box {
    margin-top: 20px;
    padding: 15px;
    border-radius: var(--radius-sm);
    font-size: 14px;
}

.result-box.success {
    background: #e8f8f0;
    color: var(--success-color);
    border: 1px solid var(--success-color);
}

.result-box.error {
    background: #fee;
    color: var(--danger-color);
    border: 1px solid var(--danger-color);
}

/* Loading */
.loading {
    text-align: center;
    padding: 40px;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 15px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Responsive */
@media (max-width: 768px) {
    .header {
        padding: 15px 20px;
    }

    .header h1 {
        font-size: 16px;
    }

    .tabs {
        padding: 15px 20px;
    }

    .tab {
        padding: 8px 15px;
        font-size: 13px;
    }

    .content {
        padding: 20px;
    }

    .sessions-management {
        grid-template-columns: 1fr;
    }

    .session-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .send-type-selector {
        flex-direction: column;
    }

    .login-form {
        padding: 30px 20px;
    }
}