:root {
    --color-bg: #F0F4F8;
    --color-white: #FFFFFF;
    --color-text-main: #2C3E50;
    --color-text-sub: #64748B;
    --color-primary: #00A0E9;
    --color-primary-hover: #0088CC;
    --color-border: #E2E8F0;
    --color-error: #DC2626;

    --font-main: 'Noto Sans JP', sans-serif;
    --font-title: 'M PLUS Rounded 1c', sans-serif;

    --shadow-sm: 0 2px 8px rgba(0, 160, 233, 0.05);
    --shadow-md: 0 8px 24px rgba(0, 160, 233, 0.12);

    --radius-md: 16px;
    --radius-sm: 8px;
}

* {
    box-sizing: border-box;
}

body {
    font-family: var(--font-main);
    background-color: var(--color-bg);
    color: var(--color-text-main);
    margin: 0;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 760px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.site-header {
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 10;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}

.site-logo {
    font-family: var(--font-title);
    font-size: 1.25rem;
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 700;
}

.site-nav {
    display: flex;
    gap: 16px;
}

.nav-link {
    color: var(--color-text-sub);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    transition: background-color 0.2s, color 0.2s;
}

.nav-link:hover {
    background-color: var(--color-bg);
    color: var(--color-primary);
}

/* Main */
.main-content {
    padding-top: 32px;
    padding-bottom: 64px;
}

.page-title {
    font-family: var(--font-title);
    font-size: 1.75rem;
    margin: 0 0 12px;
    color: var(--color-text-main);
}

.page-lead {
    color: var(--color-text-sub);
    margin: 0 0 24px;
    font-size: 0.95rem;
}

.card {
    background-color: var(--color-white);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 24px;
    margin-bottom: 20px;
}

.field-label {
    display: block;
    font-weight: 700;
    font-size: 0.95rem;
    margin-bottom: 8px;
    color: var(--color-text-main);
}

.text-area {
    width: 100%;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 12px;
    font-family: var(--font-main);
    font-size: 1rem;
    line-height: 1.7;
    resize: vertical;
    color: var(--color-text-main);
    background-color: #FAFCFE;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.text-area:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(0, 160, 233, 0.15);
}

.counter-row {
    display: flex;
    justify-content: flex-end;
    margin-top: 6px;
}

.char-counter {
    font-size: 0.8rem;
    color: var(--color-text-sub);
}

.char-counter.is-limit {
    color: var(--color-error);
    font-weight: 700;
}

.turnstile-row {
    /* invisible モードのため通常は描画されない。widgetが現れた場合のみ余白を確保する。 */
}

.turnstile-row:has(iframe) {
    margin-top: 14px;
}

.action-row {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-top: 16px;
    flex-wrap: wrap;
}

.btn-primary {
    background-color: var(--color-primary);
    color: var(--color-white);
    border: none;
    border-radius: var(--radius-sm);
    padding: 10px 24px;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.05s;
    font-family: var(--font-main);
}

.btn-primary:hover:not(:disabled) {
    background-color: var(--color-primary-hover);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(1px);
}

.btn-primary:disabled {
    background-color: #94A3B8;
    cursor: not-allowed;
}

.btn-secondary {
    background-color: var(--color-white);
    color: var(--color-primary);
    border: 1px solid var(--color-primary);
    border-radius: var(--radius-sm);
    padding: 6px 14px;
    font-size: 0.85rem;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.2s, color 0.2s;
    font-family: var(--font-main);
}

.btn-secondary:hover:not(:disabled) {
    background-color: var(--color-primary);
    color: var(--color-white);
}

.btn-secondary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.status-msg {
    font-size: 0.9rem;
    color: var(--color-text-sub);
}

.status-msg.is-error {
    color: var(--color-error);
}

/* Output */
.output-card {
    min-height: 120px;
}

.output-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 8px;
}

.output-area {
    white-space: pre-wrap;
    word-break: break-word;
    background-color: #FAFCFE;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 16px;
    min-height: 100px;
    font-size: 1rem;
    line-height: 1.8;
    color: var(--color-text-main);
}

.output-area:empty::before {
    content: 'ここに変換結果が表示されます。';
    color: var(--color-text-sub);
}

/* Note */
.note {
    color: var(--color-text-sub);
    font-size: 0.85rem;
    margin-top: 24px;
}

.note p {
    margin: 4px 0;
}

/* Footer */
.site-footer {
    background-color: var(--color-white);
    border-top: 1px solid var(--color-border);
    padding: 20px 0;
    text-align: center;
    color: var(--color-text-sub);
}

/* Loading dots */
.loading-dots::after {
    content: '';
    display: inline-block;
    width: 1em;
    text-align: left;
    animation: dots 1.2s steps(4, end) infinite;
}

@keyframes dots {
    0%   { content: ''; }
    25%  { content: '.'; }
    50%  { content: '..'; }
    75%  { content: '...'; }
    100% { content: ''; }
}

/* Responsive */
@media (max-width: 600px) {
    .page-title {
        font-size: 1.4rem;
    }

    .card {
        padding: 18px;
    }

    .header-inner {
        height: 56px;
    }

    .site-logo {
        font-size: 1.1rem;
    }
}