:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #dce5f1;
    --color-slate-900: #0f172a;
    --color-slate-800: #1e293b;
    --color-slate-600: #475569;
    --color-slate-500: #64748b;
    --color-slate-400: #94a3b8;
    --color-slate-200: #e2e8f0;
    --color-slate-100: #f1f5f9;
    --color-slate-50: #f8fafc;
    --color-orange-500: #f97316;
    --color-orange-400: #fb923c;
    --color-orange-200: #fed7aa;
    --color-orange-100: #ffedd5;
    --color-green-500: #22c55e;
    --color-green-50: #f0fdf4;
    --color-white: #ffffff;
    --color-shadow: rgba(0, 0, 0, 0.05);

    --font-main: 'Noto Sans JP', sans-serif;
}

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

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

body {
    font-family: var(--font-main);
    background-color: var(--color-slate-50);
    color: var(--color-slate-800);
    line-height: 1.6;
    overflow-x: hidden;
}

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

ul,
ol {
    list-style: none;
}

a {
    text-decoration: none;
    color: inherit;
}

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

/* Layout Containers */
.l-main {
    width: 100%;
    max-width: 1024px;
    margin: 0 auto;
    padding: 0 1rem;
}

@media (min-width: 640px) {
    .l-main {
        padding: 0 1.5rem;
    }
}

@media (min-width: 1024px) {
    .l-main {
        padding: 0 2rem;
    }
}

/* Utilities */
.u-mobile-only {
    display: block;
}

.u-desktop-only {
    display: none;
}

@media (min-width: 768px) {
    .u-mobile-only {
        display: none;
    }

    .u-desktop-only {
        display: block;
    }
}

.u-nowrap {
    white-space: nowrap;
}

/* Loading Screen */
.loading {
    position: fixed;
    inset: 0;
    background: var(--color-white);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.loading--hidden {
    opacity: 0;
    visibility: hidden;
}

.loading__spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--color-slate-100);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* Skip Link */
.skip-link {
    position: absolute;
    top: -100px;
    left: 10px;
    background: var(--color-primary);
    color: var(--color-white);
    padding: 10px 20px;
    z-index: 10000;
    transition: top 0.3s;
    font-weight: bold;
    border-radius: 4px;
}

.skip-link:focus {
    top: 10px;
}