:root {
    --seller-primary: #0b5ea8;
    --seller-primary-dark: #084a85;
    --seller-bg: #eef3fb;
    --seller-panel: #ffffff;
    --seller-text: #18314b;
    --seller-muted: #5f7a96;
    --seller-line: #cfd9e8;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Manrope", "Segoe UI", sans-serif;
    background:
        radial-gradient(900px 420px at 6% -12%, rgba(11, 94, 168, 0.15) 0%, rgba(11, 94, 168, 0) 60%),
        var(--seller-bg);
    color: var(--seller-text);
}

.seller-shell {
    min-height: 100vh;
}

.seller-header {
    position: sticky;
    top: 0;
    z-index: 900;
    background: linear-gradient(96deg, #2d6fb6 0%, #1f5ea2 100%);
    box-shadow: 0 8px 20px rgba(7, 46, 82, 0.22);
}

.seller-header-container {
    width: min(1180px, 100%);
    margin: 0 auto;
    padding: 0.72rem 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}

.seller-brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: #ffffff;
}

.seller-logo {
    width: 46px;
    height: 46px;
    border-radius: 10px;
    object-fit: cover;
}

.seller-site-name {
    font-size: 0.95rem;
    font-weight: 800;
}

.seller-nav {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.seller-nav-link {
    color: #ffffff;
    text-decoration: none;
    font-size: 0.88rem;
    font-weight: 700;
    border-radius: 8px;
    padding: 0.44rem 0.62rem;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.seller-nav-link:hover {
    background: rgba(255, 255, 255, 0.16);
}

.seller-nav-link.active {
    background: #ffffff;
    color: var(--seller-primary);
}

.seller-container {
    width: min(760px, 100%);
    margin: 18px auto 0;
    padding: 0 12px 20px;
}

.seller-card {
    background: var(--seller-panel);
    border: 1px solid var(--seller-line);
    border-radius: 14px;
    box-shadow: 0 12px 24px rgba(12, 35, 58, 0.11);
    padding: 18px;
}

.seller-card h1 {
    margin: 0;
    color: var(--seller-primary);
    font-size: 1.18rem;
}

.seller-subtitle {
    margin: 8px 0 0;
    color: var(--seller-muted);
    font-size: 0.92rem;
}

.seller-top-links {
    display: flex;
    gap: 8px;
    margin-top: 12px;
    flex-wrap: wrap;
}

.seller-link-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--seller-line);
    color: #1f3b62;
    background: #ffffff;
    border-radius: 8px;
    padding: 0.5rem 0.72rem;
    font-size: 0.9rem;
    font-weight: 700;
    text-decoration: none;
}

.seller-link-btn.active {
    background: var(--seller-primary);
    border-color: var(--seller-primary);
    color: #ffffff;
}

.flash-wrap {
    margin-top: 12px;
    display: grid;
    gap: 8px;
}

.flash {
    border-radius: 8px;
    padding: 10px 12px;
    font-size: 0.9rem;
    font-weight: 600;
}

.flash.success {
    background: #e8f7ee;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.flash.error {
    background: #fef2f2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.seller-form {
    margin-top: 14px;
}

.seller-fieldset {
    border: 1px solid #dbe3ee;
    border-radius: 10px;
    padding: 12px;
    background: #f9fbff;
    margin-bottom: 12px;
}

.seller-fieldset legend {
    color: var(--seller-primary);
    font-weight: 700;
    padding: 0 6px;
    font-size: 0.92rem;
}

.seller-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
}

.seller-group label {
    display: block;
    margin-bottom: 5px;
    font-size: 0.88rem;
    color: #374151;
    font-weight: 600;
}

.seller-group input,
.seller-group textarea {
    width: 100%;
    border: 1px solid #cfd9e6;
    border-radius: 8px;
    padding: 10px 11px;
    font-size: 0.92rem;
    color: #1f2937;
    background: #fff;
}

.seller-group textarea {
    min-height: 100px;
    resize: vertical;
}

.seller-group input:focus,
.seller-group textarea:focus {
    outline: none;
    border-color: var(--seller-primary);
    box-shadow: 0 0 0 3px rgba(0, 90, 156, 0.12);
}

.seller-input-help {
    display: block;
    margin-top: 4px;
    font-size: 0.78rem;
    color: var(--seller-muted);
}

.error-message {
    margin-top: 5px;
    font-size: 0.82rem;
    color: #b91c1c;
    display: none;
}

.error-message.show {
    display: block;
}

.submit-btn {
    width: 100%;
    border: none;
    border-radius: 10px;
    background: var(--seller-primary);
    color: #ffffff;
    padding: 12px 14px;
    font-size: 0.98rem;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.submit-btn:hover {
    background: var(--seller-primary-dark);
}

.seller-full-width {
    grid-column: 1 / -1;
}

@media (min-width: 760px) {
    .seller-grid {
        grid-template-columns: 1fr 1fr;
    }
}