:root {
    /* Base Colors - iOS 26 Liquid Palette */
    --primary-color: #007AFF; /* SF Pro Blue */
    --accent-color: #5856D6; /* SF Pro Indigo */
    --success-color: #34C759;
    --warning-color: #FF9500;
    --error-color: #FF3B30;
    
    /* Spacing & Radii */
    --radius-lg: 24px;
    --radius-md: 16px;
    --radius-sm: 8px;
    --spacing-lg: 2rem;
    --spacing-md: 1.25rem;
    --spacing-sm: 0.75rem;
    
    /* Animation */
    --transition: all 0.4s cubic-bezier(0.2, 0.8, 0.2, 1);

    /* Light Mode - Smoky Glass */
    --bg-gradient: linear-gradient(135deg, #e0c3fc 0%, #8ec5fc 100%);
    --glass-bg: rgba(255, 255, 255, 0.55);
    --glass-border: rgba(255, 255, 255, 0.4);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.15);
    --text-primary: #1d1d1f;
    --text-secondary: #424245;
    --nav-bg: rgba(255, 255, 255, 0.7);
    --input-bg: rgba(255, 255, 255, 0.4);
    --blur-amount: 25px;
}

[data-theme="dark"] {
    /* Dark Mode - Deep Liquid Glass */
    --bg-gradient: linear-gradient(135deg, #2e3192 0%, #1bffff 100%);
    --glass-bg: rgba(0, 0, 0, 0.45);
    --glass-border: rgba(255, 255, 255, 0.15);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.6);
    --text-primary: #f5f5f7;
    --text-secondary: #a1a1a6;
    --nav-bg: rgba(0, 0, 0, 0.6);
    --input-bg: rgba(0, 0, 0, 0.3);
}

* {
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
}

body {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Icons", "Helvetica Neue", Helvetica, Arial, sans-serif;
    background: var(--bg-gradient);
    background-attachment: fixed;
    background-size: cover;
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
}

/* Liquid Background Elements */
.liquid-bg {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
    overflow: hidden;
    filter: blur(80px);
    opacity: 0.6;
}

.liquid-blob {
    position: absolute;
    width: 40vw;
    height: 40vw;
    background: var(--primary-color);
    border-radius: 50%;
    mix-blend-mode: overlay;
    animation: blob-float 20s infinite alternate;
}

.liquid-blob:nth-child(2) {
    background: var(--accent-color);
    right: 0;
    bottom: 0;
    animation-delay: -5s;
}

@keyframes blob-float {
    0% { transform: translate(-10%, -10%) scale(1); }
    100% { transform: translate(20%, 20%) scale(1.2); }
}

#app {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    backdrop-filter: saturate(180%);
}

/* Glass Components */
.app-header {
    background: var(--nav-bg);
    backdrop-filter: blur(var(--blur-amount));
    -webkit-backdrop-filter: blur(var(--blur-amount));
    border-bottom: 1px solid var(--glass-border);
    padding: var(--spacing-md) var(--spacing-lg);
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.main-nav {
    display: flex;
    gap: var(--spacing-sm);
    background: rgba(255, 255, 255, 0.1);
    padding: 4px;
    border-radius: 14px;
}

.nav-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 10px 18px;
    cursor: pointer;
    border-radius: 11px;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
}

.nav-btn:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.1);
}

.nav-btn.active {
    background: var(--glass-bg);
    color: var(--primary-color);
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

/* Content Area */
.tab-content {
    flex: 1;
    padding: var(--spacing-lg);
    max-width: 1100px;
    margin: 0 auto;
    width: 100%;
}

.card {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--blur-amount));
    -webkit-backdrop-filter: blur(var(--blur-amount));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--glass-shadow);
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 40px rgba(0,0,0,0.12);
}

/* Liquid Form Elements */
.form-group {
    margin-bottom: 1.5rem;
}

label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    padding-left: 4px;
}

input, select, textarea {
    background: var(--input-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: 14px 16px;
    color: var(--text-primary);
    font-size: 1rem;
    width: 100%;
    transition: var(--transition);
}

input:focus, select:focus {
    outline: none;
    border-color: var(--primary-color);
    background: var(--glass-bg);
    box-shadow: 0 0 0 4px rgba(0, 122, 255, 0.1);
}

.btn {
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: 14px 28px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.3);
}

.btn:hover {
    transform: scale(1.02);
    filter: brightness(1.1);
    box-shadow: 0 6px 18px rgba(0, 122, 255, 0.4);
}

.btn:active {
    transform: scale(0.98);
}

.btn-secondary {
    background: var(--glass-bg);
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
}

/* Animations */
.tab-pane {
    display: none;
}

.tab-pane.active {
    display: block;
    animation: slideUp 0.6s cubic-bezier(0.2, 0.8, 0.2, 1);
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px) scale(0.98); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

/* Footer */
.app-footer {
    padding: var(--spacing-lg);
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
    backdrop-filter: blur(10px);
}

/* Responsive */
@media (max-width: 768px) {
    .app-header {
        flex-direction: column;
        gap: var(--spacing-md);
    }
    .main-nav {
        width: 100%;
        overflow-x: auto;
        padding-bottom: 8px;
    }
}