:root {
    --so-font-family-base: "Hiragino Sans", "Noto Sans JP", "Yu Gothic UI", "Segoe UI", sans-serif;

    --so-color-bg: #f7fafc;
    --so-color-surface: #ffffff;
    --so-color-surface-muted: #eef4fb;
    --so-color-text: #17253b;
    --so-color-text-muted: #506382;
    --so-color-border: #dce6f3;
    --so-color-primary: #0057a5;
    --so-color-primary-strong: #00437f;
    --so-color-success-bg: #e8f8ef;
    --so-color-success-text: #0d6a31;
    --so-color-warning-bg: #fff8e8;
    --so-color-warning-text: #7a5b00;
    --so-color-danger-bg: #fff0f0;
    --so-color-danger-text: #8c1d1d;

    --so-space-1: 0.25rem;
    --so-space-2: 0.5rem;
    --so-space-3: 0.75rem;
    --so-space-4: 1rem;
    --so-space-5: 1.25rem;
    --so-space-6: 1.5rem;

    --so-radius-sm: 8px;
    --so-radius-md: 10px;
    --so-radius-lg: 12px;
    --so-radius-pill: 999px;

    --so-shadow-sm: 0 3px 10px rgba(12, 27, 48, 0.08);
    --so-shadow-md: 0 10px 28px rgba(12, 27, 48, 0.12);

    --so-fs-sm: 0.88rem;
    --so-fs-md: 0.95rem;
    --so-fs-lg: 1.05rem;

    --so-breakpoint-sm: 560px;
    --so-breakpoint-md: 768px;
    --so-breakpoint-lg: 960px;

    /* backward compatible aliases */
    --bg: var(--so-color-bg);
    --card: var(--so-color-surface);
    --text: var(--so-color-text);
    --subtext: var(--so-color-text-muted);
    --border: var(--so-color-border);
    --primary: var(--so-color-primary);
    --primary-strong: var(--so-color-primary-strong);
    --success-bg: var(--so-color-success-bg);
    --success-text: var(--so-color-success-text);
    --warning-bg: var(--so-color-warning-bg);
    --warning-text: var(--so-color-warning-text);
    --error-bg: var(--so-color-danger-bg);
    --error-text: var(--so-color-danger-text);
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--so-font-family-base);
    background: var(--bg);
    color: var(--text);
}

.container {
    width: min(1120px, 92vw);
    margin: 0 auto;
}

.site-footer {
    margin-top: 2rem;
    border-top: 1px solid var(--border);
    background: #fff;
}

.site-footer-inner {
    padding: 1rem 0;
    color: var(--subtext);
    font-size: 0.92rem;
}

.site-footer-note {
    letter-spacing: 0.01em;
}

.page {
    padding: 1.2rem 0 2rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--so-space-2);
    border: 1px solid var(--border);
    border-radius: var(--so-radius-sm);
    background: var(--card);
    color: var(--text);
    text-decoration: none;
    font-size: var(--so-fs-md);
    font-weight: 600;
    min-height: 44px;
    padding: 0.62rem 0.95rem;
    cursor: pointer;
    line-height: 1.35;
    transition: background-color 0.16s ease, border-color 0.16s ease, color 0.16s ease;
}

.btn:hover {
    background: #f2f6fb;
}

.btn:focus-visible {
    outline: 2px solid rgba(0, 87, 165, 0.34);
    outline-offset: 2px;
}

.btn:disabled,
.btn[disabled] {
    opacity: 0.6;
    cursor: not-allowed;
    pointer-events: none;
}

.btn-sm {
    min-height: 36px;
    padding: 0.42rem 0.72rem;
    font-size: var(--so-fs-sm);
}

.btn-lg {
    min-height: 52px;
    padding: 0.78rem 1.2rem;
    font-size: 1rem;
}

.btn-block {
    width: 100%;
}

.btn-pill {
    border-radius: var(--so-radius-pill);
}

.btn-primary {
    background: var(--primary);
    border-color: var(--primary);
    color: #fff;
}

.btn-primary:hover {
    background: var(--primary-strong);
    border-color: var(--primary-strong);
}

.btn-secondary {
    background: #f4f8fd;
    border-color: #ccdae9;
    color: #223753;
}

.btn-secondary:hover {
    background: #eaf2fb;
}

.btn-danger {
    background: #fff7f7;
    border-color: #e4a8a8;
    color: #9f1f1f;
}

.btn-danger:hover {
    background: #ffecec;
}

.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--so-radius-lg);
    box-shadow: var(--so-shadow-sm);
}

.badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 1.75rem;
    padding: 0.2rem 0.45rem;
    border-radius: var(--so-radius-pill);
    font-size: 0.8rem;
    color: #fff;
    background: var(--primary);
    line-height: 1.2;
}

.form-control {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: var(--so-radius-sm);
    background: #fff;
    color: var(--text);
    font-size: 1rem;
    padding: 0.56rem 0.68rem;
}

.form-control:focus {
    border-color: #7eb3e5;
    box-shadow: 0 0 0 3px rgba(0, 87, 165, 0.15);
    outline: none;
}

.form-row {
    display: grid;
    gap: 0.38rem;
}

.form-row label {
    font-size: 0.9rem;
    color: #435b79;
    font-weight: 600;
}

.form-row input,
.form-row select,
.form-row textarea {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: var(--so-radius-sm);
    background: #fff;
    color: var(--text);
    font-size: 1rem;
    padding: 0.56rem 0.68rem;
}

.form-row input:focus,
.form-row select:focus,
.form-row textarea:focus {
    border-color: #7eb3e5;
    box-shadow: 0 0 0 3px rgba(0, 87, 165, 0.15);
    outline: none;
}

.table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.92rem;
    background: var(--card);
}

.table th,
.table td {
    border-bottom: 1px solid var(--border);
    text-align: left;
    padding: 0.72rem 0.78rem;
    vertical-align: top;
}

.table th {
    font-weight: 700;
    color: #2c4362;
    background: #f3f8ff;
}

.alert {
    border-radius: var(--so-radius-sm);
    border: 1px solid transparent;
    padding: 0.76rem 0.92rem;
    font-size: 0.92rem;
    line-height: 1.55;
}

.alert-success {
    background: var(--success-bg);
    color: var(--success-text);
    border-color: #b8e6c6;
}

.alert-warning {
    background: var(--warning-bg);
    color: var(--warning-text);
    border-color: #f1d899;
}

.alert-error {
    background: var(--error-bg);
    color: var(--error-text);
    border-color: #e7b2b2;
}

.message {
    margin-top: 0.72rem;
    border-radius: var(--so-radius-sm);
    border: 1px solid transparent;
    padding: 0.76rem 0.92rem;
    font-size: 0.92rem;
    line-height: 1.5;
}

.message-success {
    background: var(--success-bg);
    color: var(--success-text);
    border-color: #b8e6c6;
}

.message-warning {
    background: var(--warning-bg);
    color: var(--warning-text);
    border-color: #f1d899;
}

.message-error {
    background: var(--error-bg);
    color: var(--error-text);
    border-color: #e7b2b2;
}

.action-row {
    display: flex;
    align-items: center;
    gap: var(--so-space-3);
    flex-wrap: wrap;
}

.action-row-start {
    justify-content: flex-start;
}

.action-row-center {
    justify-content: center;
}

.action-row-end {
    justify-content: flex-end;
}

@media (max-width: 768px) {
    .action-row-mobile-stack {
        display: grid;
        grid-template-columns: 1fr;
    }

    .action-row-mobile-stack > .btn,
    .action-row-mobile-stack > a.btn,
    .action-row-mobile-stack > button.btn {
        width: 100%;
    }
}