/* 
 * Premium SaaS Design System (Stripe/Linear inspired)
 * Core Design Tokens & Reusable UI Components
 */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root {
    /* Color Palette */
    --saas-primary: var(--primary);
    --saas-primary-hover: var(--primary-hover);
    --saas-secondary: #f4f4f5;
    --saas-secondary-hover: #e4e4e7;
    --saas-accent: var(--secondary);
    
    --saas-bg-main: #ffffff;
    --saas-bg-subtle: #fafafa;
    
    --saas-text-main: #09090b;
    --saas-text-muted: #71717a;
    --saas-text-light: #a1a1aa;
    
    --saas-border: #e4e4e7;
    --saas-border-focus: #18181b;
    
    --saas-error: #ef4444;
    --saas-success: #10b981;
    
    /* Typography */
    --saas-font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    
    /* Shadows */
    --saas-shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --saas-shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
    --saas-shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.025);
    --saas-shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.05), 0 10px 10px -5px rgba(0, 0, 0, 0.02);
    
    /* Spacing (8px grid base) */
    --space-1: 0.25rem;  /* 4px */
    --space-2: 0.5rem;   /* 8px */
    --space-3: 0.75rem;  /* 12px */
    --space-4: 1rem;     /* 16px */
    --space-5: 1.25rem;  /* 20px */
    --space-6: 1.5rem;   /* 24px */
    --space-8: 2rem;     /* 32px */
    --space-10: 2.5rem;  /* 40px */
    --space-12: 3rem;    /* 48px */
    --space-16: 4rem;    /* 64px */
    --space-20: 5rem;    /* 80px */
    --space-24: 6rem;    /* 96px */
    
    /* Radii */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Base Styles */
body.saas-theme {
    font-family: var(--saas-font-sans);
    background-color: var(--saas-bg-main);
    color: var(--saas-text-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography */
.saas-theme h1, 
.saas-theme h2, 
.saas-theme h3, 
.saas-theme h4, 
.saas-theme h5, 
.saas-theme h6 {
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--saas-text-main);
    margin-top: 0;
}

.saas-h1 { font-size: clamp(2.5rem, 5vw, 4rem); line-height: 1.1; letter-spacing: -0.04em; }
.saas-h2 { font-size: clamp(2rem, 4vw, 3rem); line-height: 1.2; letter-spacing: -0.03em; }
.saas-h3 { font-size: clamp(1.5rem, 3vw, 2rem); line-height: 1.3; letter-spacing: -0.02em;}

.saas-text-muted { color: var(--saas-text-muted); }
.saas-text-sm { font-size: 0.875rem; }
.saas-text-xs { font-size: 0.75rem; }

/* Buttons */
.btn-saas {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-2) var(--space-4);
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    cursor: pointer;
    text-decoration: none;
    border: 1px solid transparent;
}

.btn-saas-primary {
    background-color: var(--saas-primary);
    color: #fff;
    box-shadow: var(--saas-shadow-sm);
}

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

.btn-saas-secondary {
    background-color: var(--saas-bg-main);
    color: var(--saas-text-main);
    border-color: var(--saas-border);
    box-shadow: var(--saas-shadow-sm);
}

.btn-saas-secondary:hover {
    background-color: var(--saas-secondary);
    color: var(--saas-text-main);
}

/* Forms */
.saas-input-group {
    margin-bottom: var(--space-4);
    position: relative;
}

.saas-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: var(--space-2);
    color: var(--saas-text-main);
}

.saas-input {
    width: 100%;
    padding: var(--space-2) var(--space-3);
    font-size: 0.875rem;
    line-height: 1.5;
    color: var(--saas-text-main);
    background-color: var(--saas-bg-main);
    border: 1px solid var(--saas-border);
    border-radius: var(--radius-md);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.saas-input:focus {
    outline: none;
    border-color: var(--saas-border-focus);
    box-shadow: 0 0 0 1px var(--saas-border-focus);
}

.saas-input.is-invalid {
    border-color: var(--saas-error);
}

.saas-input.is-invalid:focus {
    box-shadow: 0 0 0 1px var(--saas-error);
}

.saas-error-message {
    display: block;
    margin-top: var(--space-1);
    font-size: 0.75rem;
    color: var(--saas-error);
}

/* Cards */
.saas-card {
    background: var(--saas-bg-main);
    border: 1px solid var(--saas-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--saas-shadow-sm);
    padding: var(--space-6);
}

.saas-card-hover {
    transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

.saas-card-hover:hover {
    transform: translateY(-2px);
    box-shadow: var(--saas-shadow-md);
    border-color: #d4d4d8;
}

/* Layout */
.saas-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.saas-container-sm {
    max-width: 480px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

/* Animations */
@keyframes saasFadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.saas-animate-fade-up {
    animation: saasFadeInUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) forwards;
    opacity: 0;
}

.delay-100 { animation-delay: 100ms; }
.delay-200 { animation-delay: 200ms; }
.delay-300 { animation-delay: 300ms; }

/* Grid Background (Vercel style) */
.saas-grid-bg {
    background-size: 32px 32px;
    background-image: linear-gradient(to right, var(--saas-secondary) 1px, transparent 1px),
                      linear-gradient(to bottom, var(--saas-secondary) 1px, transparent 1px);
    mask-image: linear-gradient(to bottom, black 40%, transparent 100%);
    -webkit-mask-image: linear-gradient(to bottom, black 40%, transparent 100%);
    position: absolute;
    inset: 0;
    z-index: -1;
}

/* Badge */
.saas-badge {
    display: inline-flex;
    align-items: center;
    padding: 2px 8px;
    font-size: 0.75rem;
    font-weight: 500;
    border-radius: var(--radius-full);
    background-color: var(--saas-secondary);
    color: var(--saas-text-muted);
    border: 1px solid var(--saas-border);
}