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

:root {
    --primary-color: #6366F1;
    --primary-dark: #4F46E5;
    --primary-light: #818CF8;
    --secondary-color: #8B5CF6;
    --accent-color: #EC4899;
    --background: linear-gradient(135deg, #667EEA 0%, #764BA2 100%);
    --background-solid: #F8FAFC;
    --surface: #FFFFFF;
    --surface-glass: rgba(255, 255, 255, 0.95);
    --text-primary: #1E293B;
    --text-secondary: #64748B;
    --border-color: #E2E8F0;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-hover: 0 20px 25px -5px rgba(99, 102, 241, 0.3), 0 10px 10px -5px rgba(99, 102, 241, 0.2);
    --success: #10B981;
    --warning: #F59E0B;
    --error: #EF4444;
    --gradient-primary: linear-gradient(135deg, #667EEA 0%, #764BA2 100%);
    --gradient-secondary: linear-gradient(135deg, #F093FB 0%, #F5576C 100%);
    --gradient-accent: linear-gradient(135deg, #4FACFE 0%, #00F2FE 100%);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Inter', sans-serif;
    background: var(--background-solid);
    background-image: 
        radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.1) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(139, 92, 246, 0.1) 0px, transparent 50%);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.05) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
}

.app-container {
    max-width: 100%;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
    z-index: 1;
}

/* Header */
.app-header {
    background: var(--surface-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 16px 20px;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid rgba(226, 232, 240, 0.8);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.app-title {
    font-size: 22px;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 6px 12px;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);
    border-radius: 20px;
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.user-name {
    font-size: 14px;
    color: var(--primary-color);
    font-weight: 600;
}

/* Main Content */
.app-main {
    flex: 1;
    padding: 16px;
    padding-bottom: 80px;
}

/* Welcome Section */
.welcome-section {
    margin-bottom: 32px;
}

.welcome-card {
    background: var(--gradient-primary);
    border-radius: 24px;
    padding: 40px 28px;
    text-align: center;
    color: white;
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.welcome-card::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    animation: rotate 20s linear infinite;
}

.welcome-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

.welcome-icon {
    font-size: 64px;
    margin-bottom: 16px;
    display: inline-block;
    animation: float 3s ease-in-out infinite;
    filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.2));
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

.welcome-card h2 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 12px;
    position: relative;
    z-index: 1;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.welcome-card p {
    font-size: 16px;
    opacity: 0.95;
    position: relative;
    z-index: 1;
    font-weight: 400;
}

/* Features Section */
.features-section {
    margin-bottom: 32px;
}

.section-title {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-primary);
    letter-spacing: -0.3px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.section-title::before {
    content: '';
    width: 4px;
    height: 20px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.feature-card {
    background: var(--surface);
    border-radius: 20px;
    padding: 24px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    box-shadow: var(--shadow);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    opacity: 0;
    transition: opacity 0.4s ease;
    z-index: 0;
}

.feature-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-color);
}

.feature-card:hover::before {
    opacity: 0.05;
}

.feature-card:active {
    transform: translateY(-4px) scale(1);
}

.feature-card > * {
    position: relative;
    z-index: 1;
}

.feature-icon {
    font-size: 40px;
    margin-bottom: 12px;
    display: inline-block;
    transition: transform 0.4s ease;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
}

.feature-card:hover .feature-icon {
    transform: scale(1.1) rotate(5deg);
}

.feature-card h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 6px;
    color: var(--text-primary);
    transition: color 0.3s ease;
}

.feature-card:hover h4 {
    color: var(--primary-color);
}

.feature-card p {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Actions Section */
.actions-section {
    margin-bottom: 32px;
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.btn {
    width: 100%;
    padding: 16px 28px;
    border: none;
    border-radius: 16px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    font-family: inherit;
    position: relative;
    overflow: hidden;
    letter-spacing: 0.3px;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:active::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

.btn-primary:active {
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--surface);
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    box-shadow: var(--shadow);
}

.btn-secondary:hover {
    background: var(--gradient-primary);
    color: white;
    border-color: transparent;
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

.btn-secondary:active {
    transform: translateY(-1px);
}

/* Content Section */
.content-section {
    background: var(--surface);
    border-radius: 20px;
    padding: 28px;
    min-height: 200px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    animation: fadeInUp 0.5s ease;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.content-placeholder {
    text-align: center;
    color: var(--text-secondary);
    padding: 60px 20px;
}

.content-placeholder p {
    font-size: 16px;
    font-weight: 500;
}

/* Bottom Navigation */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--surface-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    display: flex;
    justify-content: space-around;
    padding: 12px 0 calc(12px + env(safe-area-inset-bottom));
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.1);
    z-index: 100;
    border-top: 1px solid rgba(226, 232, 240, 0.8);
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    padding: 8px 20px;
    background: none;
    border: none;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    color: var(--text-secondary);
    font-family: inherit;
    border-radius: 16px;
    position: relative;
}

.nav-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 3px;
    background: var(--gradient-primary);
    border-radius: 0 0 3px 3px;
    transition: width 0.3s ease;
}

.nav-item.active {
    color: var(--primary-color);
}

.nav-item.active::before {
    width: 40px;
}

.nav-item:hover {
    transform: translateY(-2px);
    color: var(--primary-color);
}

.nav-icon {
    font-size: 26px;
    transition: transform 0.3s ease;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
}

.nav-item:hover .nav-icon {
    transform: scale(1.1);
}

.nav-label {
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.3px;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    animation: fadeIn 0.3s ease;
}

.modal.show {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal-content {
    background: var(--surface);
    border-radius: 24px;
    padding: 32px;
    max-width: 90%;
    width: 420px;
    max-height: 85vh;
    overflow-y: auto;
    position: relative;
    animation: slideUp 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
}

.modal-close {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 300;
    color: var(--text-secondary);
    cursor: pointer;
    line-height: 1;
    transition: all 0.3s ease;
    border-radius: 50%;
    background: rgba(0, 0, 0, 0.05);
}

.modal-close:hover {
    color: var(--text-primary);
    background: rgba(0, 0, 0, 0.1);
    transform: rotate(90deg);
}

.modal-body h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-primary);
    letter-spacing: -0.5px;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.modal-body p {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.7;
    font-weight: 500;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        transform: translateY(30px) scale(0.95);
        opacity: 0;
    }
    to {
        transform: translateY(0) scale(1);
        opacity: 1;
    }
}

/* Responsive Design */
@media (max-width: 480px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }
    
    .feature-card {
        padding: 20px 16px;
    }
    
    .feature-icon {
        font-size: 36px;
    }
    
    .welcome-card {
        padding: 32px 20px;
    }
    
    .welcome-card h2 {
        font-size: 24px;
    }
    
    .app-title {
        font-size: 20px;
    }
    
    .modal-content {
        padding: 24px;
    }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --background-solid: #0F172A;
        --surface: #1E293B;
        --surface-glass: rgba(30, 41, 59, 0.95);
        --text-primary: #F1F5F9;
        --text-secondary: #94A3B8;
        --border-color: #334155;
    }
    
    body::before {
        background: 
            radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
            radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 50%);
    }
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Selection */
::selection {
    background: var(--primary-color);
    color: white;
}

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background-solid);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

/* Profile Content Styles */
.profile-content {
    text-align: center;
}

.profile-avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: var(--gradient-primary);
    margin: 0 auto 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 40px;
    color: white;
    font-weight: 700;
    box-shadow: var(--shadow-md);
    border: 4px solid var(--surface);
    transition: transform 0.3s ease;
}

.profile-avatar:hover {
    transform: scale(1.05);
}

.profile-content h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.profile-info {
    background: var(--background-solid);
    border-radius: 16px;
    overflow: hidden;
    margin-top: 24px;
    border: 1px solid var(--border-color);
}

.info-item {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.3s ease;
}

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

.info-item:hover {
    background: rgba(99, 102, 241, 0.05);
}

.info-item strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* Messages Content Styles */
.messages-content {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.message-item {
    padding: 16px 20px;
    background: var(--background-solid);
    border-radius: 16px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    cursor: pointer;
}

.message-item:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.message-item div:first-child {
    font-weight: 700;
    margin-bottom: 6px;
    color: var(--text-primary);
    font-size: 16px;
}

.message-item div:last-child {
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Settings Content Styles */
.settings-content {
    background: var(--background-solid);
    border-radius: 16px;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.setting-item {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.3s ease;
}

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

.setting-item:hover {
    background: rgba(99, 102, 241, 0.05);
}

.setting-item span:first-child {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 16px;
}

.setting-item span:last-child {
    color: var(--text-secondary);
    font-weight: 500;
}

/* Switch Toggle */
.switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 28px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--border-color);
    transition: 0.4s;
    border-radius: 28px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: 0.4s;
    border-radius: 50%;
    box-shadow: var(--shadow);
}

input:checked + .slider {
    background: var(--gradient-primary);
}

input:checked + .slider:before {
    transform: translateX(22px);
}

/* Help Content Styles */
.help-content h4 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-primary);
    letter-spacing: -0.3px;
}

.faq-item {
    padding: 20px;
    margin-bottom: 16px;
    background: var(--background-solid);
    border-radius: 16px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

.faq-item strong {
    color: var(--text-primary);
    font-weight: 700;
    font-size: 16px;
    display: block;
    margin-bottom: 12px;
}

.faq-item p {
    margin-top: 12px;
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
    font-weight: 500;
}

/* Content Section Headings */
.content-section h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-primary);
    letter-spacing: -0.5px;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}