* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: radial-gradient(circle at top right, var(--surface-3), transparent 45%),
                radial-gradient(circle at top left, var(--surface-2), transparent 38%),
                var(--theme);
    color: var(--primary);
    line-height: 1.65;
}

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

/* Shared shell foundation for research/currency pages */
.shell {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 1.2rem 2.4rem;
}

.shell-header {
    position: sticky;
    top: 0;
    z-index: 40;
    backdrop-filter: blur(10px);
    background: color-mix(in srgb, var(--theme) 88%, transparent);
    border-bottom: 1px solid var(--border);
}

.shell-header-inner {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0.85rem 1.2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.shell-brand {
    display: flex;
    flex-direction: column;
    gap: 0.08rem;
    min-width: 0;
}

.shell-brand-title {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.02em;
}

.shell-brand-subtitle {
    font-size: 0.78rem;
    color: var(--secondary);
}

.shell-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.shell-nav a {
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 0.42rem 0.72rem;
    font-size: 0.86rem;
    color: var(--secondary);
    transition: all 0.2s ease;
}

.shell-nav a:hover,
.shell-nav a.active {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-soft);
}

.hero {
    margin-top: 1.5rem;
    background: linear-gradient(140deg, color-mix(in srgb, var(--entry) 88%, var(--accent-soft)), var(--entry));
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.4rem 1.2rem;
}

.hero-title {
    margin: 0;
    font-size: clamp(1.4rem, 2.2vw, 2rem);
    line-height: 1.25;
}

.hero-subtitle {
    margin: 0.65rem 0 0;
    color: var(--secondary);
    font-size: 0.96rem;
}

.stat-grid {
    margin-top: 1rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 0.8rem;
}

.stat-card {
    border: 1px solid var(--border);
    background: var(--entry);
    border-radius: 10px;
    padding: 0.85rem;
}

.stat-label {
    color: var(--secondary);
    font-size: 0.78rem;
}

.stat-value {
    margin-top: 0.25rem;
    font-size: 1.1rem;
    font-weight: 700;
}

.section {
    margin-top: 1.3rem;
    background: var(--entry);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.15rem;
}

.section h2 {
    margin: 0;
    font-size: 1.15rem;
}

.section p {
    margin: 0.55rem 0 0;
    color: var(--secondary);
}

.container {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 1.2rem 2.4rem;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 40;
    backdrop-filter: blur(10px);
    background: color-mix(in srgb, var(--theme) 88%, transparent);
    border-bottom: 1px solid var(--border);
}

.header-content {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0.85rem 1.2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.brand-area {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    min-width: 0;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 0.35rem 0.62rem;
    color: var(--secondary);
    transition: all 0.2s ease;
}

.back-link svg {
    width: 0.9rem;
    height: 0.9rem;
    flex: 0 0 auto;
}

.back-link-text {
    font-size: 0.82rem;
    line-height: 1;
    white-space: nowrap;
}

.back-link:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-soft);
}

.brand-text {
    display: flex;
    flex-direction: column;
    gap: 0.08rem;
    min-width: 0;
}

.brand-title {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.02em;
}

.brand-subtitle {
    font-size: 0.78rem;
    color: var(--secondary);
}

.main-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.nav-item {
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 0.42rem 0.72rem;
    font-size: 0.86rem;
    color: var(--secondary);
    transition: all 0.2s ease;
}

.nav-item:hover,
.nav-item.active {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-soft);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

.lang-switch {
    display: inline-flex;
    align-items: center;
    gap: 0.16rem;
    padding: 0.2rem;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: linear-gradient(
        145deg,
        color-mix(in srgb, var(--entry) 88%, var(--surface-2)),
        color-mix(in srgb, var(--entry) 94%, var(--surface-3))
    );
    box-shadow:
        inset 0 1px 0 color-mix(in srgb, #fff 12%, transparent),
        0 5px 12px color-mix(in srgb, var(--accent) 12%, transparent);
}

.lang-switch:focus-within {
    border-color: color-mix(in srgb, var(--accent) 46%, var(--border));
    box-shadow:
        inset 0 1px 0 color-mix(in srgb, #fff 12%, transparent),
        0 0 0 2px color-mix(in srgb, var(--accent) 22%, transparent),
        0 6px 14px color-mix(in srgb, var(--accent) 14%, transparent);
}

.divider {
    font-size: 0.72rem;
    color: var(--tertiary);
    line-height: 1;
    padding: 0 0.06rem;
    user-select: none;
}

.lang-opt {
    appearance: none;
    -webkit-appearance: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid transparent;
    border-radius: 999px;
    min-height: 1.84rem;
    min-width: 2.95rem;
    padding: 0.2rem 0.78rem;
    background: transparent;
    color: var(--secondary);
    font-family: inherit;
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.02em;
    line-height: 1;
    cursor: pointer;
    transition: color 0.2s ease, background 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

.lang-opt:hover:not(:disabled) {
    color: var(--primary);
    background: color-mix(in srgb, var(--surface-2) 88%, var(--entry));
}

.lang-opt.active {
    background: var(--accent);
    border-color: color-mix(in srgb, var(--accent) 58%, var(--border));
    color: #fff;
    box-shadow: 0 7px 16px color-mix(in srgb, var(--accent) 34%, transparent);
    transform: translateY(-0.5px);
}

.lang-opt:focus-visible {
    outline: none;
    border-color: color-mix(in srgb, var(--accent) 55%, var(--border));
    box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 24%, transparent);
}

.hero-section {
    margin-top: 1.5rem;
    background: linear-gradient(140deg, color-mix(in srgb, var(--entry) 88%, var(--accent-soft)), var(--entry));
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.4rem 1.2rem;
}

.hero-header {
    margin-bottom: 0.6rem;
}

.page-title {
    margin: 0;
    font-size: clamp(1.4rem, 2.2vw, 2rem);
    line-height: 1.25;
}

.dashboard-strip {
    margin-top: 1rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 0.8rem;
}

.dash-item {
    border: 1px solid var(--border);
    background: var(--entry);
    border-radius: 10px;
    padding: 0.85rem;
}

.dash-value {
    margin-top: 0;
    font-size: 1.1rem;
    font-weight: 700;
    font-feature-settings: "tnum";
    line-height: 1.2;
}

.dash-label {
    margin-top: 0.25rem;
    color: var(--secondary);
    font-size: 0.78rem;
    text-transform: none;
    letter-spacing: normal;
}

.dash-separator {
    display: none;
}

.content-section {
    margin-top: 1.3rem;
    background: var(--entry);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.15rem;
}

.section-header {
    margin-bottom: 0;
}

.section-header h2 {
    margin: 0;
    font-size: 1.15rem;
}

.cards-grid {
    margin-top: 0.75rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 0.9rem;
}

.feature-card {
    display: flex;
    flex-direction: column;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1rem;
    background: linear-gradient(160deg, var(--entry), color-mix(in srgb, var(--entry) 92%, var(--surface-2)));
    transition: transform 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.feature-card:hover {
    transform: translateY(-1.5px);
    border-color: color-mix(in srgb, var(--accent) 42%, var(--border));
    box-shadow: 0 12px 24px color-mix(in srgb, #000 18%, transparent);
}

.card-status {
    align-self: flex-start;
    font-size: 0.74rem;
    border-radius: 999px;
    padding: 0.16rem 0.58rem;
    border: 1px solid var(--border);
    color: var(--secondary);
    white-space: nowrap;
}

.card-content {
    margin-top: 0.5rem;
    display: flex;
    flex-direction: column;
    min-height: 100%;
}

.card-title {
    margin: 0;
    font-size: 1rem;
    font-weight: 700;
}

.mini-stats {
    margin-top: 0.62rem;
    padding: 0.6rem;
    border: 1px solid color-mix(in srgb, var(--border) 90%, var(--surface-3));
    border-radius: 10px;
    background: color-mix(in srgb, var(--entry) 90%, var(--surface-3));
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0.55rem;
}

.stat-pair {
    min-width: 0;
}

.stat-pair .label {
    display: block;
    margin: 0;
    color: var(--tertiary);
    font-size: 0.72rem;
    line-height: 1.25;
}

.stat-pair .val {
    display: block;
    margin-top: 0.22rem;
    font-size: 0.86rem;
    font-weight: 650;
    line-height: 1.35;
    color: var(--primary);
    overflow-wrap: anywhere;
}

.card-action {
    margin-top: 0.82rem;
}

.action-btn {
    border: 1px solid var(--accent);
    background: var(--accent);
    color: #fff;
    border-radius: 9px;
    padding: 0.42rem 0.72rem;
    font-size: 0.84rem;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    transition: all 0.18s ease;
}

.action-btn:hover {
    filter: brightness(0.95);
}

.simple-grid {
    margin-top: 0.85rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
    gap: 0.7rem;
}

.simple-card {
    border: 1px dashed var(--tertiary);
    border-radius: 10px;
    padding: 0.8rem;
    background: color-mix(in srgb, var(--entry) 92%, var(--surface-3));
}

.simple-card h3 {
    margin: 0;
    font-size: 0.95rem;
}

.simple-card p {
    margin: 0.45rem 0 0;
    color: var(--secondary);
    font-size: 0.85rem;
}

.disclaimer {
    margin-top: 1rem;
    color: var(--secondary);
    font-size: 0.8rem;
}

@media (max-width: 900px) {
    .header-content {
        flex-wrap: wrap;
        justify-content: space-between;
    }

    .main-nav {
        order: 3;
        width: 100%;
        margin-top: 0.2rem;
    }
}

@media (max-width: 760px) {
    .shell-header-inner {
        flex-direction: column;
        align-items: flex-start;
    }

    .shell-nav {
        width: 100%;
    }

    .shell-nav a {
        flex: 1;
        text-align: center;
    }

    .header-content {
        flex-direction: column;
        align-items: flex-start;
    }

    .brand-area {
        width: 100%;
        justify-content: space-between;
    }

    .main-nav {
        width: 100%;
    }

    .nav-item {
        flex: 1;
        text-align: center;
    }

    .header-actions {
        width: 100%;
        justify-content: flex-end;
    }

    .mini-stats {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .lang-opt {
        min-height: 1.74rem;
        min-width: 2.72rem;
        font-size: 0.76rem;
    }
}