:root {
    --skin-bg: #f4f4f4;
    --skin-surface: #ffffff;
    --skin-surface-soft: #f8fafc;
    --skin-text: #1f2937;
    --skin-muted: #6b7280;
    --skin-line: #d1d5db;
    --skin-primary: #2563eb;
    --skin-primary-hover: #1d4ed8;
    --skin-danger: #dc2626;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: var(--skin-bg);
    color: var(--skin-text);
}

.skin-shell {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    padding: 0.9rem 1.5rem 0;
    flex-wrap: wrap;
}

.topbar-links,
.topbar-auth {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.skin-brand {
    display: inline-flex;
    align-items: center;
    gap: 0;
    flex: 0 0 auto;
    text-decoration: none;
    border: 0;
    background: transparent;
    padding: 0.1rem 0;
    margin-right: auto;
}

.skin-brand-logo {
    display: block;
    height: 88px;
    width: auto;
    max-width: 340px;
    object-fit: contain;
}

.topbar a,
.skin-chip,
.auth-trigger,
.user-toggle,
.auth-submit,
.auth-secondary {
    border: 1px solid var(--skin-line);
    border-radius: 0.5rem;
    background: var(--skin-surface);
    color: var(--skin-text);
    text-decoration: none;
    padding: 0.7rem 0.95rem;
    font: inherit;
    cursor: pointer;
}

.topbar .skin-brand {
    padding: 0.1rem 0;
    background: transparent;
    border: 0;
    color: inherit;
}

.topbar a:hover,
.auth-trigger:hover,
.user-toggle:hover,
.auth-secondary:hover {
    border-color: #9ca3af;
}

.skin-header {
    padding: 1.25rem 1.5rem 1.5rem;
}

.skin-title {
    margin: 0 0 0.55rem;
    font-size: 0.92rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--skin-muted);
}

.skin-hero {
    max-width: 72rem;
    margin: 0 auto;
    padding: 1.5rem;
    border: 1px solid var(--skin-line);
    border-radius: 1rem;
    background:
        radial-gradient(circle at top left, rgba(37, 99, 235, 0.12), transparent 28rem),
        linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.05);
}

.skin-hero h1 {
    margin: 0;
    font-size: clamp(2rem, 4vw, 3.2rem);
    line-height: 1.08;
    color: #0f172a;
}

.skin-hero p {
    margin: 0.85rem 0 0;
    max-width: 42rem;
    font-size: 1.05rem;
    line-height: 1.7;
    color: #475569;
}

.skin-hero-actions {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
    margin-top: 1.1rem;
}

.skin-hero-note {
    margin-top: 1rem;
    font-size: 0.95rem;
    color: var(--skin-muted);
}

.auth-card {
    margin-top: 1.25rem;
    max-width: 28rem;
    padding: 1rem;
    border: 1px solid var(--skin-line);
    border-radius: 0.85rem;
    background: rgba(255, 255, 255, 0.92);
}

.auth-card h2 {
    margin: 0 0 0.4rem;
    font-size: 1.1rem;
}

.auth-card p {
    margin: 0 0 0.85rem;
    color: var(--skin-muted);
    font-size: 0.95rem;
}

.auth-card .auth-trigger {
    background: var(--skin-primary);
    border-color: var(--skin-primary);
    color: #fff;
}

.skin-main {
    flex: 1;
    padding: 0 1.5rem 3rem;
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 1.5rem;
    max-width: 72rem;
    width: 100%;
    margin: 0 auto;
    box-sizing: border-box;
}

.skin-navigation,
.skin-footer,
.skin-zone {
    padding: 1rem 1.25rem;
    background: rgba(255, 255, 255, 0.86);
    border: 1px solid var(--skin-line);
    border-radius: 1rem;
}

.skin-content-shell {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 1.25rem;
}

.skin-article {
    padding: 1.25rem;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 1rem;
    border: 1px solid var(--skin-line);
}

.skin-sidebar {
    padding: 1rem 1.25rem;
    background: var(--skin-surface-soft);
    border-radius: 1rem;
    border: 1px solid var(--skin-line);
}

.auth-modal {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    background: rgba(15, 23, 42, 0.55);
    z-index: 1000;
}

.hidden {
    display: none;
}

.auth-box {
    width: 100%;
    max-width: 26rem;
    background: #fff;
    border-radius: 1rem;
    border: 1px solid var(--skin-line);
    box-shadow: 0 20px 50px rgba(15, 23, 42, 0.25);
    padding: 1.5rem;
    position: relative;
}

.auth-close {
    position: absolute;
    top: 0.9rem;
    right: 0.9rem;
    border: 0;
    background: transparent;
    font-size: 1.4rem;
    cursor: pointer;
    color: var(--skin-muted);
}

.auth-box h2 {
    margin: 0 0 1rem;
    font-size: 1.4rem;
}

.auth-box label {
    display: block;
    margin-bottom: 0.35rem;
    font-weight: 600;
    font-size: 0.92rem;
}

.auth-box input {
    width: 100%;
    box-sizing: border-box;
    border: 1px solid var(--skin-line);
    border-radius: 0.6rem;
    padding: 0.75rem 0.9rem;
    margin-bottom: 0.9rem;
    font: inherit;
}

.auth-submit {
    width: 100%;
    background: var(--skin-primary);
    border-color: var(--skin-primary);
    color: #fff;
    font-weight: 700;
}

.auth-submit:hover,
.auth-card .auth-trigger:hover {
    background: var(--skin-primary-hover);
    border-color: var(--skin-primary-hover);
}

.auth-switch {
    margin-top: 0.95rem;
    text-align: center;
    color: var(--skin-muted);
    font-size: 0.92rem;
}

.auth-switch button {
    border: 0;
    background: transparent;
    color: var(--skin-primary);
    cursor: pointer;
    font: inherit;
    font-weight: 700;
}

.auth-message {
    min-height: 1.25rem;
    margin: 0.4rem 0 0;
    font-size: 0.92rem;
    color: var(--skin-danger);
}

.user-menu {
    position: relative;
}

.user-dropdown {
    position: absolute;
    right: 0;
    top: calc(100% + 0.45rem);
    min-width: 14rem;
    border: 1px solid var(--skin-line);
    border-radius: 0.85rem;
    background: #fff;
    box-shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
    padding: 0.45rem;
    z-index: 40;
}

.user-dropdown a,
.user-dropdown button {
    display: block;
    width: 100%;
    box-sizing: border-box;
    text-align: left;
    border: 0;
    background: transparent;
    text-decoration: none;
    color: var(--skin-text);
    padding: 0.7rem 0.8rem;
    border-radius: 0.6rem;
    font: inherit;
    cursor: pointer;
}

.user-dropdown a:hover,
.user-dropdown button:hover {
    background: #f3f4f6;
}

@media (min-width: 960px) {
    .skin-content-shell {
        grid-template-columns: minmax(0, 1fr) 18rem;
        align-items: start;
    }
}

@media (max-width: 640px) {
    .topbar,
    .skin-header,
    .skin-main {
        padding-left: 1rem;
        padding-right: 1rem;
    }

    .skin-hero {
        padding: 1.2rem;
    }
}