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

:root {
    --primary-color: #e91e63;
    --primary-dark: #c2185b;
    --secondary-color: #9c27b0;
    --accent-color: #ff6b9d;
    --success-color: #4caf50;
    --warning-color: #ff9800;
    --error-color: #f44336;
    --bg-color: #f5f5f5;
    --card-bg: #ffffff;
    --text-primary: #212121;
    --text-secondary: #757575;
    --border-color: #e0e0e0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.15);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
}

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

.screen.active {
    display: block;
}

/* Authentication Screen */
#auth-screen {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 20px;
}

.auth-container {
    background: var(--card-bg);
    border-radius: 20px;
    box-shadow: var(--shadow-lg);
    padding: 40px;
    width: 100%;
    max-width: 450px;
}

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

.auth-header i {
    font-size: 48px;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.auth-header h1 {
    color: var(--text-primary);
    margin-bottom: 10px;
    font-size: 28px;
}

.auth-header p {
    color: var(--text-secondary);
    font-size: 14px;
}

.auth-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    border-bottom: 2px solid var(--border-color);
    position: relative;
    z-index: 10;
}

.tab-btn {
    flex: 1;
    padding: 12px;
    border: none;
    background: transparent;
    cursor: pointer;
    font-size: 16px;
    color: var(--text-secondary);
    border-bottom: 3px solid transparent;
    transition: all 0.3s;
    position: relative;
    z-index: 1;
    user-select: none;
}

.tab-btn:hover {
    color: var(--primary-color);
    background: rgba(233, 30, 99, 0.05);
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
    font-weight: 600;
}

.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
}

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

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

.form-group label i {
    margin-right: 8px;
    color: var(--primary-color);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 15px;
    transition: border-color 0.3s;
    font-family: inherit;
}

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

.form-group textarea {
    resize: vertical;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    width: 100%;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-secondary {
    background: var(--text-secondary);
    color: white;
    padding: 8px 16px;
    width: auto;
}

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

.error-message {
    color: var(--error-color);
    margin-top: 10px;
    font-size: 14px;
    display: none;
}

.error-message.show {
    display: block;
}

.success-message {
    color: var(--success-color);
    margin-top: 10px;
    font-size: 14px;
    display: none;
}

.success-message.show {
    display: block;
}

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

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 600;
    color: var(--primary-color);
}

.nav-brand i {
    font-size: 24px;
}

.nav-user {
    display: flex;
    align-items: center;
    gap: 15px;
}

.dashboard-container {
    display: flex;
    min-height: calc(100vh - 70px);
}

/* Sidebar */
.sidebar {
    width: 250px;
    background: var(--card-bg);
    box-shadow: var(--shadow);
    padding: 20px 0;
}

.nav-menu {
    list-style: none;
}

.nav-menu li {
    margin-bottom: 5px;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 15px 25px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.3s;
    border-left: 3px solid transparent;
}

.nav-link:hover {
    background: rgba(233, 30, 99, 0.1);
    color: var(--primary-color);
}

.nav-link.active {
    background: rgba(233, 30, 99, 0.1);
    color: var(--primary-color);
    border-left-color: var(--primary-color);
    font-weight: 600;
}

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

/* Main Content */
.main-content {
    flex: 1;
    padding: 30px;
    overflow-y: auto;
}

.content-section {
    display: none;
}

.content-section.active {
    display: block;
}

.content-section h2 {
    color: var(--text-primary);
    margin-bottom: 25px;
    font-size: 28px;
}

.content-section h3 {
    color: var(--text-primary);
    margin-bottom: 20px;
    font-size: 22px;
}

/* Notifications */
.notifications-container {
    margin-bottom: 20px;
}

.notification {
    background: var(--warning-color);
    color: white;
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 12px;
    box-shadow: var(--shadow);
    animation: slideIn 0.3s ease;
}

.notification i {
    font-size: 20px;
}

@keyframes slideIn {
    from {
        transform: translateX(-100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

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

.stat-card {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 20px;
    transition: transform 0.3s;
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.stat-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 24px;
}

.stat-info h3 {
    font-size: 28px;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.stat-info p {
    color: var(--text-secondary);
    font-size: 14px;
}

/* Forms */
.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.health-form {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    max-width: 800px;
}

/* Recent Activity */
.recent-activity {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.record-item {
    padding: 15px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.record-item:last-child {
    border-bottom: none;
}

.record-date {
    color: var(--text-secondary);
    font-size: 14px;
}

/* Charts */
.chart-container {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 25px;
}

/* Appointments */
.appointment-form-container {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.appointments-list {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.appointment-item {
    padding: 20px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 15px;
    transition: all 0.3s;
}

.appointment-item:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow);
}

.appointment-item.upcoming {
    border-color: var(--warning-color);
    background: rgba(255, 152, 0, 0.05);
}

.appointment-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.appointment-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
}

.appointment-date {
    color: var(--text-secondary);
    font-size: 14px;
}

.appointment-details {
    display: flex;
    gap: 20px;
    margin-top: 10px;
    flex-wrap: wrap;
}

.appointment-detail {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 14px;
}

.appointment-detail i {
    color: var(--primary-color);
}

.delete-btn {
    background: var(--error-color);
    color: white;
    border: none;
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 12px;
    margin-top: 10px;
}

.delete-btn:hover {
    background: #d32f2f;
}

/* Tips */
.tips-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.tip-card {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--primary-color);
    transition: transform 0.3s;
}

.tip-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.tip-category {
    color: var(--primary-color);
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    margin-bottom: 10px;
}

.tip-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.tip-content {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.9);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

.loading-overlay.show {
    display: flex;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Empty State */
.empty-state {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 48px;
    margin-bottom: 15px;
    color: var(--border-color);
}

/* Password Strength Indicator */
.password-strength {
    margin-top: 8px;
    font-size: 12px;
}

.strength-bar {
    height: 4px;
    background: var(--border-color);
    border-radius: 2px;
    overflow: hidden;
    margin-bottom: 5px;
}

.strength-fill {
    height: 100%;
    transition: width 0.3s, background-color 0.3s;
    border-radius: 2px;
}

.strength-text {
    font-size: 12px;
    font-weight: 600;
}

/* Responsive Design */
@media (max-width: 768px) {
    .dashboard-container {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        padding: 10px 0;
    }

    .nav-menu {
        display: flex;
        overflow-x: auto;
        padding: 0 10px;
    }

    .nav-menu li {
        margin-bottom: 0;
        margin-right: 5px;
    }

    .nav-link {
        padding: 10px 15px;
        white-space: nowrap;
    }

    .main-content {
        padding: 20px;
    }

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

    .form-row {
        grid-template-columns: 1fr;
    }

    .auth-container {
        padding: 30px 20px;
    }
}