:root {
    --nav-bg: #f5f5f7;
    --nav-card: #ffffff;
    --nav-text: #1d1d1f;
    --nav-muted: #86868b;
    --nav-line: #e5e5ea;
    --nav-accent: #0071e3;
    --nav-permanent-bg: #fff8e6;
    --nav-permanent-border: #f5d565;
    --nav-font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", sans-serif;
}

* {
    box-sizing: border-box;
}

.nav-body {
    margin: 0;
    min-height: 100vh;
    font-family: var(--nav-font);
    color: var(--nav-text);
    background: var(--nav-bg);
    -webkit-font-smoothing: antialiased;
}

.nav-page {
    max-width: 400px;
    margin: 0 auto;
    padding: 32px 20px 48px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.nav-header {
    text-align: center;
    margin-bottom: 32px;
}

.nav-permanent {
    display: block;
    margin-bottom: 24px;
    padding: 14px 16px;
    border-radius: 12px;
    background: var(--nav-permanent-bg);
    border: 1px solid var(--nav-permanent-border);
}

.nav-permanent-label {
    display: block;
    font-size: 12px;
    color: #9a6700;
    margin-bottom: 4px;
}

.nav-permanent-url {
    display: block;
    font-size: 20px;
    font-weight: 700;
    color: #1d1d1f;
    letter-spacing: 0.01em;
}

.nav-title {
    margin: 0 0 6px;
    font-size: 22px;
    font-weight: 600;
    letter-spacing: -0.01em;
}

.nav-subtitle {
    margin: 0;
    font-size: 14px;
    line-height: 1.5;
    color: var(--nav-muted);
}

.nav-routes {
    display: flex;
    flex-direction: column;
    gap: 12px;
    flex: 1;
}

.nav-route-card {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 18px 20px;
    border-radius: 14px;
    text-decoration: none;
    color: inherit;
    background: var(--nav-card);
    border: 1px solid var(--nav-line);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
    transition: border-color 0.15s ease, box-shadow 0.15s ease, opacity 0.15s ease;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
    user-select: none;
}

.nav-route-card:active {
    background: #fafafa;
}

.nav-route-card.is-loading {
    pointer-events: none;
    opacity: 0.72;
}

.nav-route-card.is-loading .nav-route-arrow {
    animation: nav-spin 0.7s linear infinite;
}

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

.nav-route-card:hover,
.nav-route-card:focus-visible {
    border-color: #c7c7cc;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
}

.nav-route-main {
    flex: 1;
    min-width: 0;
}

.nav-route-name {
    display: block;
    font-size: 17px;
    font-weight: 600;
    margin-bottom: 2px;
}

.nav-route-desc {
    display: block;
    font-size: 13px;
    color: var(--nav-muted);
}

.nav-route-arrow {
    flex-shrink: 0;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--nav-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--nav-accent);
}

.nav-route-arrow svg {
    width: 18px;
    height: 18px;
}

.nav-empty {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 40px 20px;
    border-radius: 14px;
    background: var(--nav-card);
    border: 1px solid var(--nav-line);
    color: var(--nav-muted);
    font-size: 14px;
}

.nav-empty-hint {
    margin-top: 8px;
    font-size: 13px;
}

.nav-footer {
    margin-top: 32px;
    text-align: center;
    font-size: 12px;
    line-height: 1.6;
    color: var(--nav-muted);
}

.nav-footer strong {
    color: var(--nav-text);
    font-weight: 600;
}

.nav-tip {
    margin-top: 20px;
    padding: 12px 14px;
    border-radius: 10px;
    background: var(--nav-card);
    border: 1px solid var(--nav-line);
    font-size: 12px;
    line-height: 1.55;
    color: var(--nav-muted);
    text-align: center;
}