/* ===== Hướng dẫn Story Machine — layout sidebar + nội dung nhiều ảnh ===== */
:root {
    --bg: #07070f;
    --panel: rgba(255, 255, 255, .035);
    --panel-2: rgba(255, 255, 255, .06);
    --border: rgba(255, 255, 255, .09);
    --border-h: rgba(240, 184, 73, .38);
    --text: #f6f5f4;
    --dim: #9a97ae;
    --amber: #f0b849;
    --violet: #8b5cf6;
    --green: #34d399;
    --warn: #fbbf24;
    --r: 12px;
    --font: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
    --serif: 'Fraunces', Georgia, serif;
    --mono: 'JetBrains Mono', Consolas, monospace;
    --nav-h: 56px;
    --sb-w: 264px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0 }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 20px) }
body {
    background: var(--bg);
    background-image: radial-gradient(circle 600px at 85% 4%, rgba(240, 184, 73, .07) 0%, transparent 70%),
                      radial-gradient(circle 500px at 5% 40%, rgba(139, 92, 246, .06) 0%, transparent 70%);
    background-attachment: fixed;
    color: var(--text); font-family: var(--font); line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}
.mono { font-family: var(--mono) }
.accent { color: var(--amber) }
.muted { color: var(--dim) }
code {
    font-family: var(--mono); font-size: .85em; padding: .1em .4em; border-radius: 5px;
    background: rgba(240, 184, 73, .1); color: var(--amber); border: 1px solid rgba(240, 184, 73, .18);
}
a { color: var(--amber) }

/* ===== NAV ===== */
.gnav {
    position: fixed; inset: 0 0 auto 0; height: var(--nav-h); z-index: 60;
    background: rgba(7, 7, 15, .9); backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border);
}
.gnav-in { height: 100%; padding: 0 1.2rem; display: flex; align-items: center; gap: 1rem }
.gnav-logo {
    display: flex; align-items: center; gap: .5rem; font-size: .74rem; font-weight: 700;
    letter-spacing: .09em; color: var(--text); text-decoration: none; white-space: nowrap;
}
.gnav-ic { width: 20px; height: 20px; border-radius: 5px; object-fit: cover }
.gnav-right { margin-left: auto; display: flex; align-items: center; gap: 1.1rem }
.gnav-right a { color: var(--dim); text-decoration: none; font-size: .85rem; transition: color .2s }
.gnav-right a:hover { color: var(--amber) }
.lang-toggle {
    display: inline-flex; align-items: center; gap: .32rem; padding: .22rem .55rem;
    border: 1px solid var(--border); border-radius: 999px; font-size: .74rem;
}
.lang-toggle:hover { border-color: var(--border-h) }
.burger { display: none; background: none; border: 0; color: var(--text); font-size: 1.05rem; cursor: pointer }

/* ===== LAYOUT ===== */
.layout { display: flex; max-width: 1360px; margin: 0 auto; padding-top: var(--nav-h) }
.sidebar {
    width: var(--sb-w); flex: none; position: sticky; top: var(--nav-h); align-self: flex-start;
    height: calc(100vh - var(--nav-h)); overflow-y: auto; padding: 1.6rem 1rem 3rem;
    border-right: 1px solid var(--border);
}
.sb-title { font-size: .62rem; letter-spacing: .18em; color: var(--dim); margin-bottom: .8rem; padding-left: .6rem }
.sb-group { font-size: .6rem; letter-spacing: .16em; color: var(--amber); margin: 1.3rem 0 .5rem; padding-left: .6rem }
.sb-link {
    display: flex; align-items: center; gap: .5rem; padding: .42rem .6rem; border-radius: 8px;
    color: var(--dim); text-decoration: none; font-size: .86rem; border-left: 2px solid transparent;
    transition: background .18s, color .18s, border-color .18s;
}
.sb-link:hover { background: var(--panel); color: var(--text) }
.sb-link.active { color: var(--amber); background: rgba(240, 184, 73, .08); border-left-color: var(--amber) }
.sb-n { font-family: var(--mono); font-size: .68rem; opacity: .75 }

.content { flex: 1; min-width: 0; padding: 2.4rem 2.2rem 5rem }

/* ===== HERO ===== */
.kicker { display: block; font-size: .66rem; letter-spacing: .18em; color: var(--amber); margin-bottom: .6rem }
.ghero h1 {
    font-family: var(--serif); font-weight: 600; font-size: clamp(1.9rem, 4vw, 2.7rem);
    letter-spacing: -.02em; line-height: 1.12;
}
.lede { color: var(--dim); margin-top: .8rem; max-width: 46rem; font-size: 1.02rem }
.lede b, .ul b, .sect p b, .note b, .req b { color: var(--text); font-weight: 600 }

/* ===== SECTIONS ===== */
.sect { margin-top: 3.6rem; scroll-margin-top: calc(var(--nav-h) + 16px) }
.sect h2 {
    font-family: var(--serif); font-weight: 600; font-size: clamp(1.45rem, 2.7vw, 1.95rem);
    letter-spacing: -.015em; margin-bottom: .7rem; padding-bottom: .55rem;
    border-bottom: 1px solid var(--border);
}
.sect h3 { font-size: 1.1rem; font-weight: 600; margin: 2rem 0 .5rem }
.sect p { color: var(--dim); margin-bottom: .9rem; max-width: 50rem }
.step-badge {
    display: inline-block; font-size: .62rem; letter-spacing: .14em; color: var(--amber);
    background: rgba(240, 184, 73, .1); border: 1px solid rgba(240, 184, 73, .28);
    border-radius: 999px; padding: .16rem .6rem; margin-bottom: .6rem;
}
.ul { list-style: none; margin: 0 0 1.1rem; padding: 0; max-width: 50rem }
.ul li { color: var(--dim); padding-left: 1.15rem; position: relative; margin-bottom: .5rem }
.ul li::before { content: '▸'; position: absolute; left: 0; color: var(--amber) }

/* ===== FIGURES (điểm nhấn của trang) ===== */
.fig { margin: 1.4rem 0 1.8rem }
.fig img {
    display: block; width: 100%; height: auto; border-radius: var(--r);
    border: 1px solid var(--border); box-shadow: 0 16px 44px rgba(0, 0, 0, .5);
    cursor: zoom-in; transition: transform .3s, border-color .3s;
}
.fig img:hover { transform: translateY(-3px); border-color: var(--border-h) }
.fig figcaption { margin-top: .6rem; font-size: .82rem; color: var(--dim) }
.fig-lead img { border-color: rgba(240, 184, 73, .22) }

/* ===== CARDS ===== */
.cards-3, .cards-2 { display: grid; gap: 1rem; margin: 1.2rem 0 }
.cards-3 { grid-template-columns: repeat(auto-fit, minmax(215px, 1fr)) }
.cards-2 { grid-template-columns: repeat(auto-fit, minmax(255px, 1fr)) }
.card {
    border: 1px solid var(--border); border-radius: var(--r); padding: 1.1rem;
    background: var(--panel); transition: border-color .2s, background .2s;
}
.card:hover { border-color: var(--border-h); background: var(--panel-2) }
.card-ic { font-size: 1.3rem; display: block; margin-bottom: .5rem }
.card h4 { font-size: .98rem; margin-bottom: .3rem }
.card p { font-size: .86rem; color: var(--dim); margin: 0 }

/* ===== REQUIREMENTS ===== */
.req { display: flex; flex-direction: column; gap: .7rem; margin: 1.2rem 0 }
.req-row {
    display: flex; gap: .8rem; align-items: flex-start; padding: .85rem 1rem;
    border: 1px solid var(--border); border-radius: var(--r); background: var(--panel);
}
.req-n {
    flex: none; width: 24px; height: 24px; display: grid; place-items: center; font-size: .72rem;
    border-radius: 50%; background: rgba(240, 184, 73, .14); color: var(--amber);
    border: 1px solid rgba(240, 184, 73, .3);
}
.req-row .muted { display: block; font-size: .85rem; margin-top: .15rem }

/* ===== NOTES ===== */
.note {
    display: flex; gap: .8rem; padding: .95rem 1.1rem; border-radius: var(--r); margin: 1.2rem 0;
    background: rgba(240, 184, 73, .07); border: 1px solid rgba(240, 184, 73, .22); font-size: .92rem;
}
.note i { color: var(--amber); margin-top: .2rem }
.note div { color: var(--dim) }
.note.warn { background: rgba(251, 191, 36, .07); border-color: rgba(251, 191, 36, .25) }
.note.warn i { color: var(--warn) }
.note.ok { background: rgba(52, 211, 153, .07); border-color: rgba(52, 211, 153, .25) }
.note.ok i { color: var(--green) }

/* ===== FAQ ===== */
.faq { display: flex; flex-direction: column; gap: .55rem }
.faq details {
    border: 1px solid var(--border); border-radius: var(--r); background: var(--panel);
    overflow: hidden; transition: border-color .2s;
}
.faq details[open] { border-color: var(--border-h) }
.faq summary {
    cursor: pointer; padding: .8rem 1rem; font-weight: 500; font-size: .93rem;
    list-style: none; display: flex; align-items: center; gap: .5rem;
}
.faq summary::-webkit-details-marker { display: none }
.faq summary::before { content: '+'; color: var(--amber); font-family: var(--mono); flex: none }
.faq details[open] summary::before { content: '−' }
.faq details p { padding: 0 1rem .9rem 2rem; margin: 0; color: var(--dim); font-size: .89rem }

/* ===== FOOTER ===== */
.gfoot { margin-top: 4rem; padding-top: 2rem; border-top: 1px solid var(--border) }
.btn-back {
    display: inline-flex; align-items: center; gap: .5rem; padding: .65rem 1.15rem; border-radius: 10px;
    background: var(--panel); border: 1px solid var(--border); color: var(--text);
    text-decoration: none; font-size: .9rem; font-weight: 500; transition: border-color .2s, background .2s;
}
.btn-back:hover { border-color: var(--border-h); background: var(--panel-2) }
.gfoot .muted { margin-top: 1.2rem; font-size: .8rem }

/* ===== LIGHTBOX ===== */
.lightbox {
    position: fixed; inset: 0; z-index: 100; display: none; place-items: center;
    background: rgba(4, 4, 10, .93); padding: 2rem; cursor: zoom-out;
}
.lightbox.open { display: grid }
.lightbox img { max-width: 100%; max-height: 92vh; border-radius: 10px; border: 1px solid var(--border) }
.lb-close {
    position: absolute; top: 1rem; right: 1.4rem; background: none; border: 0;
    color: var(--text); font-size: 2rem; line-height: 1; cursor: pointer; opacity: .7;
}
.lb-close:hover { opacity: 1 }

/* ===== RESPONSIVE ===== */
.sb-overlay { display: none }
@media (max-width: 980px) {
    .burger { display: block }
    .sidebar {
        position: fixed; top: var(--nav-h); left: 0; z-index: 55; background: #0a0a14;
        transform: translateX(-100%); transition: transform .25s ease;
    }
    .sidebar.open { transform: none }
    .sb-overlay { position: fixed; inset: var(--nav-h) 0 0 0; z-index: 54; background: rgba(0, 0, 0, .55) }
    .sb-overlay.show { display: block }
    .content { padding: 1.8rem 1.2rem 4rem }
    .gnav-right .gnav-link span { display: none }
}
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto }
    .fig img:hover, .card:hover { transform: none }
}