/* ============================================================
   LTL Portfolio — main.css
   Editorial tối giản · Lora + Be Vietnam Pro · off-white + xanh đậm
   ============================================================ */

/* ---------- Tokens ---------- */
:root {
  --color-bg:       #faf8f4;
  --color-surface:  #ffffff;
  --color-ink:      #1a1a17;
  --color-muted:    #6b675f;
  --color-line:     #e6e1d8;
  --color-accent:   #2f5d50;
  --color-accent-2: #3f7a69;

  --font-display: "Lora", Georgia, "Times New Roman", serif;
  --font-body:    "Be Vietnam Pro", system-ui, -apple-system, sans-serif;

  --measure: 68ch;
  --maxw:    1080px;
  --radius:  10px;

  --step--1: clamp(0.83rem, 0.8rem + 0.15vw, 0.9rem);
  --step-0:  clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
  --step-1:  clamp(1.2rem, 1.1rem + 0.5vw, 1.35rem);
  --step-2:  clamp(1.5rem, 1.3rem + 1vw, 2.05rem);
  --step-3:  clamp(2.1rem, 1.6rem + 2.4vw, 3.4rem);
}

/* ---------- Reset nhẹ ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  /* texture rất nhẹ: gradient mờ tạo chiều sâu, không lòe loẹt */
  background-image:
    radial-gradient(60rem 60rem at 110% -10%, rgba(47, 93, 80, 0.05), transparent 60%),
    radial-gradient(50rem 50rem at -10% 110%, rgba(47, 93, 80, 0.04), transparent 60%);
  background-attachment: fixed;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--color-accent); text-decoration: none; }

h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 600; line-height: 1.15; letter-spacing: -0.01em; }

/* ---------- Layout helpers ---------- */
.container { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: clamp(1.1rem, 4vw, 2.5rem); }
.section { padding-block: clamp(2.5rem, 6vw, 4.5rem); }
.section__head { margin-bottom: 2rem; }
.section__title { font-size: var(--step-2); }

.eyebrow {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 0.6rem;
}

/* ---------- Skip link / a11y ---------- */
.screen-reader-text {
  position: absolute !important; width: 1px; height: 1px; padding: 0;
  overflow: hidden; clip: rect(1px, 1px, 1px, 1px); white-space: nowrap; border: 0;
}
.skip-link:focus {
  position: fixed; top: 0.5rem; left: 0.5rem; z-index: 1000; width: auto; height: auto;
  clip: auto; background: var(--color-ink); color: #fff; padding: 0.6rem 1rem; border-radius: 6px;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--color-bg) 86%, transparent);
  backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--color-line);
}
.site-header__inner { display: flex; align-items: center; justify-content: space-between; min-height: 54px; gap: 1rem; }
.site-brand { display: inline-flex; align-items: center; gap: 0.6rem; color: var(--color-ink); }
.site-brand__name { font-family: var(--font-display); font-weight: 600; font-size: 1.15rem; letter-spacing: -0.01em; }
.site-brand img { width: 36px; height: 36px; border-radius: 50%; }

.site-menu { display: flex; gap: 1.6rem; list-style: none; padding: 0; align-items: center; }
.site-menu a {
  color: var(--color-ink); font-size: 0.95rem; font-weight: 500; padding-block: 0.3rem;
  background-image: linear-gradient(var(--color-accent), var(--color-accent));
  background-repeat: no-repeat; background-position: 0 100%; background-size: 0% 1.5px;
  transition: background-size 0.28s ease;
}
.site-menu a:hover, .site-menu .current-menu-item > a { background-size: 100% 1.5px; }

.nav-toggle { display: none; }

/* ---------- Hero ---------- */
.hero { padding-block: clamp(1.6rem, 4vw, 2.8rem) clamp(2rem, 5vw, 3.5rem); max-width: 56rem; }
.hero__title { font-size: var(--step-3); margin-bottom: 1.2rem; }
.hero__intro { font-size: var(--step-1); color: var(--color-ink); max-width: var(--measure); }
.hero__intro p { margin-bottom: 1rem; }
.hero__actions { display: flex; flex-wrap: wrap; gap: 0.8rem; margin-top: 2rem; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 0.4rem;
  font-weight: 600; font-size: 0.95rem; padding: 0.7rem 1.3rem; border-radius: 999px;
  border: 1px solid transparent; transition: transform 0.15s ease, background 0.2s ease, color 0.2s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn--primary { background: var(--color-accent); color: #fff; }
.btn--primary:hover { background: var(--color-accent-2); }
.btn--ghost { border-color: var(--color-line); color: var(--color-ink); background: transparent; }
.btn--ghost:hover { border-color: var(--color-accent); color: var(--color-accent); }

/* ---------- Project grid ---------- */
.project-grid { list-style: none; padding: 0; display: grid; gap: 1.4rem; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }
.project-card {
  background: var(--color-surface); border: 1px solid var(--color-line); border-radius: var(--radius);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.project-card:hover { transform: translateY(-3px); border-color: color-mix(in srgb, var(--color-accent) 35%, var(--color-line)); box-shadow: 0 14px 30px -18px rgba(26,26,23,0.4); }
.project-card__link { display: block; padding: 1.5rem 1.5rem 1.6rem; height: 100%; color: var(--color-ink); }
.project-card__num { font-family: var(--font-display); font-size: 0.95rem; color: var(--color-accent); font-weight: 600; letter-spacing: 0.04em; }
.project-card__title { font-size: var(--step-1); margin: 0.4rem 0 0.6rem; }
.project-card__excerpt { color: var(--color-muted); font-size: 0.95rem; line-height: 1.65; }
.project-card__cta { display: inline-block; margin-top: 1rem; color: var(--color-accent); font-weight: 600; font-size: 0.9rem; }
.project-card:hover .project-card__cta { text-decoration: underline; text-underline-offset: 3px; }

/* ---------- Page / Prose ---------- */
.page { padding-block: clamp(1.1rem, 3vw, 1.8rem) clamp(2.2rem, 6vw, 4rem); }
.page__head { margin-bottom: 1.8rem; max-width: var(--measure); }
.page__title { font-size: var(--step-2); }
.page__back { display: inline-block; font-size: 0.9rem; color: var(--color-muted); margin-bottom: 0.8rem; }
.page__back:hover { color: var(--color-accent); }

.prose { max-width: var(--measure); }
.prose--narrow { max-width: 60ch; }
.prose > * + * { margin-top: 1.1rem; }
.prose h2 { font-size: var(--step-2); margin-top: 2.6rem; padding-top: 0.4rem; }
.prose h3 { font-size: var(--step-1); margin-top: 1.8rem; }
.prose h2:first-child, .prose h3:first-child { margin-top: 0; }
.prose p, .prose li { color: var(--color-ink); }
.prose a { background-image: linear-gradient(var(--color-accent), var(--color-accent)); background-repeat: no-repeat; background-position: 0 100%; background-size: 100% 1px; transition: background-size 0.2s; }
.prose a:hover { background-size: 100% 2px; }
.prose ul, .prose ol { padding-left: 1.4rem; }
.prose li + li { margin-top: 0.4rem; }
.prose img { border-radius: var(--radius); border: 1px solid var(--color-line); margin-block: 1.5rem; }
.prose strong { font-weight: 600; }
.prose hr { border: none; border-top: 1px solid var(--color-line); margin-block: 2.5rem; }

/* Blockquote → hộp callout nhấn */
.prose blockquote {
  border-left: 3px solid var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 6%, var(--color-surface));
  padding: 1rem 1.3rem; border-radius: 0 var(--radius) var(--radius) 0; color: var(--color-ink);
}
.prose blockquote p { margin: 0; }
.prose blockquote > * + * { margin-top: 0.6rem; }

/* Code */
.prose code { font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace; font-size: 0.88em; background: color-mix(in srgb, var(--color-ink) 6%, transparent); padding: 0.12em 0.4em; border-radius: 5px; }
.prose pre { background: var(--color-ink); color: #f4f1ea; padding: 1.1rem 1.3rem; border-radius: var(--radius); overflow-x: auto; font-size: 0.9rem; line-height: 1.6; }
.prose pre code { background: none; padding: 0; color: inherit; }

/* Bảng */
.prose table { width: 100%; border-collapse: collapse; font-size: 0.94rem; margin-block: 1.5rem; display: block; overflow-x: auto; }
.prose thead { background: color-mix(in srgb, var(--color-accent) 8%, var(--color-surface)); }
.prose th, .prose td { text-align: left; padding: 0.65rem 0.9rem; border: 1px solid var(--color-line); vertical-align: top; }
.prose th { font-weight: 600; font-family: var(--font-body); }
.prose tbody tr:nth-child(even) { background: color-mix(in srgb, var(--color-ink) 2.5%, transparent); }

/* ---------- Post nav (prev/next bài) ---------- */
.post-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top: 3rem; padding-top: 1.8rem; border-top: 1px solid var(--color-line); }
.post-nav a { display: block; padding: 1rem 1.1rem; border: 1px solid var(--color-line); border-radius: var(--radius); background: var(--color-surface); transition: border-color 0.2s, transform 0.15s; }
.post-nav a:hover { border-color: var(--color-accent); transform: translateY(-2px); }
.post-nav__label { display: block; font-size: 0.74rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--color-muted); font-weight: 600; }
.post-nav__title { display: block; font-family: var(--font-display); font-weight: 600; margin-top: 0.3rem; color: var(--color-ink); }
.post-nav__next { text-align: right; }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--color-line); margin-top: 3rem; background: color-mix(in srgb, var(--color-ink) 3%, var(--color-bg)); }
.site-footer__inner { padding-block: 2.4rem; display: flex; flex-wrap: wrap; align-items: center; gap: 0.6rem 1.6rem; }
.site-footer__brand { font-family: var(--font-display); font-weight: 600; font-size: 1.1rem; }
.site-footer__meta { color: var(--color-muted); font-size: 0.88rem; flex: 1 1 320px; }
.site-footer__nav { display: flex; gap: 1.2rem; }
.site-footer__nav a { color: var(--color-muted); font-size: 0.9rem; }
.site-footer__nav a:hover { color: var(--color-accent); }

/* ---------- Post list (fallback index) ---------- */
.post-list__item { padding-block: 1.4rem; border-bottom: 1px solid var(--color-line); }
.post-list__title { font-size: var(--step-1); }

/* ---------- Reveal animation ---------- */
.reveal { opacity: 0; transform: translateY(8px); animation: ltl-reveal 0.6s ease forwards; animation-delay: var(--d, 0ms); }
@keyframes ltl-reveal { to { opacity: 1; transform: none; } }

/* ---------- Responsive ---------- */
@media (max-width: 720px) {
  .nav-toggle {
    display: inline-flex; align-items: center; justify-content: center; width: 42px; height: 42px;
    background: transparent; border: 1px solid var(--color-line); border-radius: 8px; cursor: pointer; position: relative;
  }
  .nav-toggle__bar, .nav-toggle__bar::before, .nav-toggle__bar::after {
    content: ""; position: absolute; width: 18px; height: 2px; background: var(--color-ink); transition: transform 0.25s, opacity 0.2s;
  }
  .nav-toggle__bar { position: static; }
  .nav-toggle__bar::before { transform: translateY(-6px); }
  .nav-toggle__bar::after { transform: translateY(6px); }
  .site-nav { position: relative; }
  .site-menu {
    display: none; position: absolute; right: 0; top: calc(100% + 10px); flex-direction: column;
    gap: 0; background: var(--color-surface); border: 1px solid var(--color-line); border-radius: var(--radius);
    padding: 0.5rem; min-width: 200px; box-shadow: 0 16px 40px -22px rgba(26,26,23,0.5);
  }
  .site-nav.is-open .site-menu { display: flex; }
  .site-nav.is-open .nav-toggle__bar { background: transparent; }
  .site-nav.is-open .nav-toggle__bar::before { transform: rotate(45deg); }
  .site-nav.is-open .nav-toggle__bar::after { transform: rotate(-45deg); }
  .site-menu a { padding: 0.6rem 0.8rem; width: 100%; background-size: 0 0 !important; border-radius: 6px; }
  .site-menu a:hover { background: color-mix(in srgb, var(--color-accent) 8%, transparent); }
  .post-nav { grid-template-columns: 1fr; }
  .post-nav__next { text-align: left; }
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; scroll-behavior: auto !important; }
  .reveal { opacity: 1; transform: none; }
}