/* ============================
   LAYOUT
   ============================ */

.container { max-width: 1100px; margin: 0 auto; padding: 0 2rem; }

/* ============================
   NAV
   ============================ */

nav:not(.toc-rail) {
    position: fixed; top: 0; width: 100%; z-index: 100;
    padding: 1.5rem 0;
    background: var(--nav-bg);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--steel-border);
    transition: background 0.5s ease, border-color 0.5s ease;
}
nav:not(.toc-rail) .container { display: flex; justify-content: space-between; align-items: center; }

.nav-logo {
    font-size: 0.85rem; font-weight: 500; letter-spacing: 0.15em;
    color: var(--text-primary); text-decoration: none;
    transition: color 0.5s ease;
}
.nav-logo span { color: var(--accent-orange); transition: color 0.5s ease; }

.nav-right { display: flex; align-items: center; gap: 2rem; }
.nav-links { display: flex; gap: 2rem; list-style: none; }
.nav-links a {
    font-size: 0.75rem; letter-spacing: 0.1em; text-transform: uppercase;
    color: var(--text-secondary); text-decoration: none;
    transition: color 0.3s ease; position: relative;
}
.nav-links a::after {
    content: ''; position: absolute; bottom: -4px; left: 0;
    width: 0; height: 1px; background: var(--accent-orange);
    transition: width 0.3s ease;
}
.nav-links a:hover { color: var(--text-primary); }
.nav-links a:hover::after { width: 100%; }

/* ============================
   THEME TOGGLE
   ============================ */

.theme-toggle {
    display: flex; align-items: center; justify-content: center;
    width: 32px; height: 32px;
    border: 1px solid var(--steel-border); border-radius: 2px;
    background: var(--toggle-bg); cursor: pointer;
    transition: border-color 0.3s ease, background 0.5s ease;
    position: relative;
}
.theme-toggle:hover { border-color: var(--steel-border-hover); }

.toggle-half {
    width: 14px; height: 14px;
    border-radius: 50%;
    border: 1.5px solid var(--toggle-fill);
    position: relative; overflow: hidden;
    transition: border-color 0.5s ease, transform 0.4s ease;
}
.toggle-half::after {
    content: ''; position: absolute;
    top: 0; left: 0; width: 50%; height: 100%;
    background: var(--toggle-fill);
    transition: background 0.5s ease, left 0.4s ease;
}
[data-theme="dark"] .toggle-half::after { left: 0; }
[data-theme="light"] .toggle-half::after { left: 50%; }
[data-theme="light"] .toggle-half { transform: rotate(180deg); }

/* ============================
   SECTION HEADERS
   ============================ */

.section-header { display: flex; align-items: center; gap: 1rem; margin-bottom: 3rem; }
.section-label {
    font-size: 0.7rem; letter-spacing: 0.25em; text-transform: uppercase;
    color: var(--accent-orange); font-weight: 500; white-space: nowrap;
    transition: color 0.5s ease;
}
.section-line { flex: 1; height: 1px; background: var(--steel-border); transition: background 0.5s ease; }
.section-index { font-size: 0.7rem; color: var(--text-dim); letter-spacing: 0.1em; transition: color 0.5s ease; }

/* ============================
   PROSE
   ============================ */

.prose { font-size: 0.95rem; line-height: 1.8; color: var(--text-secondary); font-weight: 300; }
.prose p + p { margin-top: 1.5rem; }
.prose strong { color: var(--text-primary); font-weight: 500; }

/* ============================
   FOOTER
   ============================ */

footer { padding: 3rem 0; border-top: 1px solid var(--steel-border); transition: border-color 0.5s ease; }
.footer-content { display: flex; justify-content: space-between; align-items: center; }
.footer-left { font-size: 0.75rem; color: var(--text-dim); letter-spacing: 0.08em; transition: color 0.5s ease; }
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a {
    font-size: 0.75rem; letter-spacing: 0.08em; text-transform: uppercase;
    color: var(--text-dim); text-decoration: none; transition: color 0.3s ease;
}
.footer-links a:hover { color: var(--accent-orange); }

/* ============================
   RESPONSIVE — SHARED
   ============================ */

@media (max-width: 768px) {
    .footer-content { flex-direction: column; gap: 1rem; text-align: center; }

    nav:not(.toc-rail) { padding: 1rem 0; }
    nav:not(.toc-rail) .container {
        display: grid;
        grid-template-columns: 1fr auto;
        grid-template-rows: auto auto;
        align-items: center;
    }
    .nav-logo { grid-column: 1; grid-row: 1; }
    .nav-right { display: contents; }
    .theme-toggle { grid-column: 2; grid-row: 1; }
    .nav-links {
        grid-column: 1 / -1;
        grid-row: 2;
        display: flex;
        gap: 1.5rem;
        padding-top: 0.75rem;
        margin-top: 0.75rem;
        border-top: 1px solid var(--steel-border);
        justify-content: center;
    }
}