:root {
    --color-bg: #f4f6fb;
    --color-text: #1f2937;
    --color-muted: #6b7280;
    --color-accent: #0f4c81;
    --color-card: #ffffff;
    --color-border: #e5e7eb;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    background: var(--color-bg);
    color: var(--color-text);
    font-family: "Segoe UI", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
    line-height: 1.6;
}

.site-inner {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 20px;
}

.site-header,
.site-footer {
    background: var(--color-card);
    border-bottom: 1px solid var(--color-border);
}

.site-footer {
    border-bottom: 0;
    border-top: 1px solid var(--color-border);
    color: var(--color-muted);
    font-size: 13px;
}

.site-header .site-inner,
.site-footer .site-inner {
    display: flex;
    align-items: center;
    min-height: 64px;
}

.site-logo {
    color: var(--color-accent);
    font-weight: 700;
    text-decoration: none;
}

.site-main {
    min-height: calc(100vh - 140px);
    padding: 48px 0;
}

.hero {
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 32px;
    box-shadow: 0 10px 24px rgba(0, 0, 0, 0.04);
}

.hero h1 {
    margin: 0 0 12px;
    font-size: 28px;
}

.hero p {
    margin: 0;
    color: var(--color-muted);
}

.flash {
    padding: 12px 16px;
    border-radius: 8px;
    margin-bottom: 16px;
}

.flash-success {
    background: #ecfdf3;
    color: #166534;
}

.flash-error {
    background: #fef2f2;
    color: #991b1b;
}

a {
    color: var(--color-accent);
}

.hero-error h1 {
    color: #991b1b;
}

.btn-home {
    display: inline-block;
    margin-top: 16px;
    padding: 10px 18px;
    background: var(--color-accent);
    color: #ffffff;
    text-decoration: none;
    border-radius: 8px;
}

.error-modal-overlay {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(17, 24, 39, 0.55);
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.error-modal-overlay.is-open {
    display: flex;
}

.error-modal {
    width: 100%;
    max-width: 400px;
    background: var(--color-card);
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 16px 40px rgba(0, 0, 0, 0.18);
}

.error-modal h2 {
    margin: 0 0 12px;
    font-size: 18px;
}

.error-modal p {
    margin: 0 0 20px;
    color: var(--color-text);
}

.error-modal-close {
    display: inline-block;
    min-width: 88px;
    padding: 8px 16px;
    border: 0;
    border-radius: 8px;
    background: var(--color-accent);
    color: #ffffff;
    font-size: 14px;
    cursor: pointer;
}