/* Design System - Variables */

:root {
    /* Color Palette - qr.io inspired */
    --color-primary: #0f172a;
    --color-accent: #14b8a6;
    --color-accent-hover: #0d9488;
    --color-bg: #ffffff;
    --color-bg-secondary: #f8fafc;
    --color-bg-tertiary: #f1f5f9;
    --color-text: #1e293b;
    --color-text-secondary: #64748b;
    --color-border: #e2e8f0;
    --color-border-hover: #cbd5e1;
    --color-error: #ef4444;
    --color-success: #10b981;

    /* Spacing Scale (8px base) */
    --spacing-xs: 0.25rem;  /* 4px */
    --spacing-sm: 0.5rem;   /* 8px */
    --spacing-md: 1rem;     /* 16px */
    --spacing-lg: 1.5rem;   /* 24px */
    --spacing-xl: 2rem;     /* 32px */
    --spacing-2xl: 3rem;    /* 48px */
    --spacing-3xl: 4rem;    /* 64px */

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-size-xs: 0.75rem;    /* 12px */
    --font-size-sm: 0.875rem;   /* 14px */
    --font-size-base: 1rem;     /* 16px */
    --font-size-lg: 1.125rem;   /* 18px */
    --font-size-xl: 1.25rem;    /* 20px */
    --font-size-2xl: 1.5rem;    /* 24px */
    --font-size-3xl: 1.875rem;  /* 30px */
    --font-size-4xl: 2.25rem;   /* 36px */

    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;

    /* Border Radius */
    --radius-sm: 0.25rem;   /* 4px */
    --radius-md: 0.5rem;    /* 8px */
    --radius-lg: 0.75rem;   /* 12px */
    --radius-xl: 1rem;      /* 16px */
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 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);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Z-index Scale */
    --z-base: 1;
    --z-dropdown: 10;
    --z-sticky: 20;
    --z-modal-backdrop: 40;
    --z-modal: 50;
    --z-tooltip: 60;

    /* Layout Breakpoints */
    --breakpoint-mobile: 768px;
    --breakpoint-tablet: 1024px;
    --breakpoint-desktop: 1280px;

    /* Component Specific */
    --input-panel-width: 400px;
    --input-panel-width-tablet: 320px;
    --qr-preview-max-width: 600px;
    --header-height: 80px;
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-text);
    background-color: var(--color-bg-secondary);
}

/* Focus Styles for Accessibility */
*:focus {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

*:focus:not(:focus-visible) {
    outline: none;
}

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

::-webkit-scrollbar-track {
    background: var(--color-bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-border-hover);
}