/* ===== CSS Variables ===== */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary: #64748b;
    --accent: #8b5cf6;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    
    --border-color: #e2e8f0;
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --border-radius-xl: 16px;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;
    
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-serif: 'Playfair Display', Georgia, serif;
    --font-mono: 'Roboto Mono', monospace;
    
    --navbar-height: 64px;
}

/* ===== Reset & Base ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    color: var(--text-primary);
    background: var(--bg-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary-dark);
}

img {
    max-width: 100%;
    height: auto;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

input, textarea, select {
    font-family: inherit;
    font-size: 1rem;
}

ul {
    list-style: none;
}

.hidden {
    display: none !important;
}

/* ===== Utility Classes ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.section-header {
    text-align: center;
    margin-bottom: 48px;
}

.section-header h2 {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.section-header p {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    transition: all var(--transition-fast);
    white-space: nowrap;
}

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

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

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

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

.btn-large {
    padding: 16px 32px;
    font-size: 1.125rem;
}

.btn-small {
    padding: 8px 16px;
    font-size: 0.875rem;
}

.btn-add {
    width: 100%;
    padding: 16px;
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    color: var(--text-secondary);
    font-weight: 500;
    transition: all var(--transition-fast);
}

.btn-add:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: rgba(37, 99, 235, 0.05);
}

/* ===== Navigation ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--navbar-height);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.logo-icon {
    font-size: 1.5rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
}

.nav-link:hover {
    color: var(--text-primary);
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all var(--transition-fast);
}

.mobile-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: white;
    border-bottom: 1px solid var(--border-color);
    padding: 16px 24px;
    flex-direction: column;
    gap: 16px;
}

.mobile-menu.active {
    display: flex;
}

/* ===== Form Elements ===== */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.char-count {
    display: block;
    margin-top: 8px;
    font-size: 0.75rem;
    color: var(--text-muted);
    text-align: right;
}

/* ===== Toast Notifications ===== */
.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    padding: 12px 24px;
    background: var(--text-primary);
    color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    z-index: 2000;
    transition: transform var(--transition-normal);
}

.toast.show {
    transform: translateX(-50%) translateY(0);
}

/* ===== Modal ===== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    padding: 24px;
}

.modal {
    background: white;
    border-radius: var(--border-radius-xl);
    max-width: 480px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
}

.modal-close {
    position: absolute;
    top: 16px;
    right: 16px;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    font-size: 1.25rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.premium-modal .modal-content {
    padding: 48px 32px;
    text-align: center;
}

.premium-icon {
    font-size: 3rem;
    margin-bottom: 16px;
}

.premium-modal h2 {
    font-size: 1.75rem;
    margin-bottom: 8px;
}

.premium-modal > .modal-content > p {
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.premium-features {
    text-align: left;
    margin-bottom: 24px;
    padding: 0 16px;
}

.premium-features li {
    padding: 8px 0;
    color: var(--text-secondary);
}

.premium-price {
    margin-bottom: 24px;
}

.premium-price .price {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.premium-price .period {
    display: block;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.guarantee {
    margin-top: 16px;
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    :root {
        --navbar-height: 56px;
    }
    
    .nav-links {
        display: none;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .section-header h2 {
        font-size: 1.75rem;
    }
    
    .section-header p {
        font-size: 1rem;
    }
    
    .btn-large {
        padding: 14px 24px;
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }
    
    .modal {
        margin: 16px;
    }
    
    .premium-modal .modal-content {
        padding: 32px 24px;
    }
}