/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --color-bg: #fafafa;
    --color-surface: #ffffff;
    --color-text: #1a1a2e;
    --color-text-muted: #6b7280;
    --color-border: #e5e7eb;
    --color-primary: #111827;
    --color-primary-hover: #374151;
    --color-accent: #e53e3e;
    --color-green: #059669;
    --color-green-bg: #d1fae5;
    --color-red: #dc2626;
    --color-red-bg: #fee2e2;
    --color-gray-bg: #f3f4f6;
    --radius: 8px;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --transition: 150ms ease;
}

html { font-size: 15px; }
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1080px;
    margin: 0 auto;
    padding: 0 1.5rem;
    width: 100%;
}

a { color: var(--color-primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-accent); }

h1 { font-size: 2rem; font-weight: 700; line-height: 1.2; margin-bottom: 0.5rem; }
h2 { font-size: 1.5rem; font-weight: 600; line-height: 1.3; margin-bottom: 0.5rem; }
h3 { font-size: 1.15rem; font-weight: 600; margin-bottom: 0.4rem; }
h4 { font-size: 0.95rem; font-weight: 600; margin-bottom: 0.3rem; text-transform: uppercase; letter-spacing: 0.03em; color: var(--color-text-muted); }
p { margin-bottom: 1rem; color: var(--color-text-muted); }

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-family: inherit;
    font-weight: 500;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    line-height: 1;
}
.btn-primary {
    background: var(--color-primary);
    color: #fff;
    padding: 0.65rem 1.4rem;
    font-size: 0.9rem;
}
.btn-primary:hover { background: var(--color-primary-hover); color: #fff; }
.btn-outline {
    background: transparent;
    color: var(--color-text);
    border: 1px solid var(--color-border);
    padding: 0.65rem 1.4rem;
    font-size: 0.9rem;
}
.btn-outline:hover { border-color: var(--color-text); color: var(--color-text); }
.btn-sm { padding: 0.4rem 0.9rem; font-size: 0.8rem; }
.btn-danger { background: transparent; color: var(--color-red); border: 1px solid var(--color-red-bg); padding: 0.3rem 0.6rem; font-size: 0.75rem; }
.btn-danger:hover { background: var(--color-red-bg); color: var(--color-red); }

button[type="submit"] {
    font-family: inherit;
    font-weight: 500;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all var(--transition);
}

/* ===== Header ===== */
.site-header {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
}
.header-inner {
    display: flex;
    align-items: center;
    height: 56px;
    gap: 2rem;
}
.logo {
    display: flex;
    align-items: center;
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--color-text);
    flex-shrink: 0;
}
.logo:hover { color: var(--color-text); }
.site-nav { display: flex; gap: 1.5rem; }
.site-nav a { font-size: 0.9rem; color: var(--color-text-muted); font-weight: 500; }
.site-nav a:hover { color: var(--color-text); }
.user-nav { display: flex; gap: 1rem; align-items: center; margin-left: auto; }
.user-nav a { font-size: 0.9rem; color: var(--color-text-muted); font-weight: 500; }
.user-nav a:hover { color: var(--color-text); }

.mobile-toggle { display: none; background: none; border: none; cursor: pointer; padding: 0.5rem; flex-direction: column; gap: 4px; }
.mobile-toggle span { display: block; width: 20px; height: 2px; background: var(--color-text); transition: all var(--transition); }

/* ===== Main ===== */
main { flex: 1; padding: 2rem 0; }

/* ===== Forms ===== */
input, select, textarea {
    font-family: inherit;
    font-size: 0.9rem;
    padding: 0.6rem 0.8rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    background: var(--color-surface);
    color: var(--color-text);
    width: 100%;
    transition: border-color var(--transition);
}
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(17,24,39,0.08);
}
label {
    display: block;
    font-size: 0.85rem;
    font-weight: 500;
    margin-bottom: 0.3rem;
    color: var(--color-text);
}
small { font-size: 0.8rem; color: var(--color-text-muted); }
form .form-group { margin-bottom: 1.2rem; }

/* ===== Cards ===== */
.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
}
.card-compact { padding: 1rem; }

/* ===== Tables ===== */
table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
thead th {
    text-align: left;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--color-text-muted);
    padding: 0.6rem 0.8rem;
    border-bottom: 2px solid var(--color-border);
}
tbody td {
    padding: 0.7rem 0.8rem;
    border-bottom: 1px solid var(--color-border);
    vertical-align: middle;
}
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: var(--color-gray-bg); }

/* ===== Size Tags ===== */
.sizes-list { display: flex; gap: 0.3rem; flex-wrap: wrap; }
.size-tag {
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 500;
    white-space: nowrap;
}
.size-tag.available { background: var(--color-green-bg); color: var(--color-green); }
.size-tag.unavailable { background: var(--color-red-bg); color: var(--color-red); }
.size-tag.unknown { background: var(--color-gray-bg); color: var(--color-text-muted); }

/* ===== Status badges ===== */
.badge-available { color: var(--color-green); font-weight: 600; }
.badge-unavailable { color: var(--color-red); }

/* ===== Alerts ===== */
.alert { padding: 0.8rem 1rem; border-radius: var(--radius); font-size: 0.9rem; margin-bottom: 1rem; }
.alert-error { background: var(--color-red-bg); color: var(--color-red); }
.alert-success { background: var(--color-green-bg); color: var(--color-green); }

/* ===== Details/FAQ ===== */
details {
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    margin-bottom: 0.5rem;
    background: var(--color-surface);
}
details summary {
    padding: 1rem 1.2rem;
    cursor: pointer;
    font-weight: 500;
    font-size: 0.95rem;
    list-style: none;
}
details summary::before { content: '+ '; color: var(--color-text-muted); font-weight: 400; }
details[open] summary::before { content: '- '; }
details summary::-webkit-details-marker { display: none; }
details > *:not(summary) { padding: 0 1.2rem 1rem; }
details p { font-size: 0.9rem; }

/* ===== Hero ===== */
.hero {
    text-align: center;
    padding: 4rem 0 3rem;
}
.hero h1 { font-size: 2.5rem; margin-bottom: 1rem; color: var(--color-text); }
.hero p { font-size: 1.15rem; max-width: 560px; margin: 0 auto 1.5rem; }

/* ===== Grid ===== */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }

/* ===== Section ===== */
.section { padding: 3rem 0; }
.section-header { text-align: center; margin-bottom: 2rem; }
.section-header h2 { color: var(--color-text); }

/* ===== Footer ===== */
.site-footer {
    background: var(--color-text);
    color: rgba(255,255,255,0.7);
    margin-top: auto;
    padding-top: 3rem;
}
.footer-inner { display: flex; justify-content: space-between; gap: 3rem; padding-bottom: 2rem; }
.footer-brand { max-width: 300px; }
.footer-brand strong { color: #fff; font-size: 1.1rem; display: block; margin-bottom: 0.5rem; }
.footer-brand p { color: rgba(255,255,255,0.5); font-size: 0.85rem; margin: 0; }
.footer-links { display: flex; gap: 4rem; }
.footer-links h4 { color: rgba(255,255,255,0.4); font-size: 0.75rem; margin-bottom: 0.8rem; }
.footer-links a { display: block; color: rgba(255,255,255,0.7); font-size: 0.85rem; margin-bottom: 0.5rem; }
.footer-links a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.1); padding: 1.2rem 0; }
.footer-bottom small { color: rgba(255,255,255,0.3); }

/* ===== Auth pages ===== */
.auth-card {
    max-width: 400px;
    margin: 2rem auto;
}

/* ===== Blog ===== */
.blog-article { max-width: 720px; margin: 0 auto; padding: 1rem 0; }
.blog-article header { margin-bottom: 2rem; }
.blog-article h1 { font-size: 2rem; }
.blog-article h2 { margin-top: 2rem; }
.blog-article p, .blog-article li { font-size: 0.95rem; line-height: 1.7; }
.blog-article ul, .blog-article ol { margin-bottom: 1rem; padding-left: 1.5rem; color: var(--color-text-muted); }
.blog-article li { margin-bottom: 0.4rem; }

.blog-cta {
    margin-top: 3rem;
    padding: 2rem;
    background: var(--color-gray-bg);
    border-radius: var(--radius);
    text-align: center;
}
.blog-cta h3 { color: var(--color-text); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
    html { font-size: 14px; }
    .hero h1 { font-size: 1.8rem; }
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .footer-inner { flex-direction: column; gap: 2rem; }
    .footer-links { gap: 2rem; }

    .site-nav, .user-nav { display: none; }
    .mobile-toggle { display: flex; margin-left: auto; }

    .nav-open .site-nav,
    .nav-open .user-nav {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 56px;
        left: 0;
        right: 0;
        background: var(--color-surface);
        border-bottom: 1px solid var(--color-border);
        padding: 1rem 1.5rem;
        box-shadow: var(--shadow-md);
    }
    .nav-open .user-nav { top: auto; border-top: 1px solid var(--color-border); }

    table { font-size: 0.8rem; }
    thead th, tbody td { padding: 0.5rem; }
}