/* ============================================
   Base Styles
   ============================================ */

/* CSS Variables */
:root {
    /* Colors */
    --color-primary: #4F46E5;
    --color-primary-dark: #4338CA;
    --color-primary-light: #818CF8;
    --color-secondary: #06B6D4;
    --color-accent: #F59E0B;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-blue: linear-gradient(135deg, #4F46E5 0%, #06B6D4 100%);
    --gradient-purple: linear-gradient(135deg, #9333EA 0%, #DB2777 100%);
    --gradient-green: linear-gradient(135deg, #10B981 0%, #059669 100%);
    --gradient-orange: linear-gradient(135deg, #F59E0B 0%, #EF4444 100%);

    /* Text Colors */
    --color-text-primary: #0F172A;
    --color-text-secondary: #475569;
    --color-text-tertiary: #94A3B8;
    --color-text-inverse: #FFFFFF;

    /* Background Colors */
    --color-bg-primary: #FFFFFF;
    --color-bg-secondary: #F8FAFC;
    --color-bg-tertiary: #F1F5F9;
    --color-bg-dark: #0F172A;
    --color-bg-dark-secondary: #1E293B;

    /* Border Colors */
    --color-border: #E2E8F0;
    --color-border-light: #F1F5F9;

    /* 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);

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    --font-size-6xl: 3.75rem;

    /* Line Heights */
    --leading-tight: 1.25;
    --leading-normal: 1.5;
    --leading-relaxed: 1.75;

    /* Font Weights */
    --font-normal: 400;
    --font-medium: 500;
    --font-semibold: 600;
    --font-bold: 700;
}

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

/* Base */
html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    line-height: var(--leading-normal);
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    overflow-x: hidden;
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding-left: var(--spacing-lg);
    padding-right: var(--spacing-lg);
}

/* Responsive helpers */
.pc-only {
    display: inline;
}

.sp-only {
    display: none;
}

@media (max-width: 768px) {
    .container {
        padding-left: var(--spacing-md);
        padding-right: var(--spacing-md);
    }

    .pc-only {
        display: none;
    }

    .sp-only {
        display: inline;
    }
}

/* Links */
a {
    color: inherit;
    text-decoration: none;
}

/* Images */
img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* Lists */
ul, ol {
    list-style: none;
}

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

/* Focus visible */
*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Selection */
::selection {
    background-color: var(--color-primary-light);
    color: var(--color-text-inverse);
}