/* ============================================================
   IDN MONTERREY — Hoja de estilos
   Sistema editorial / institucional: esquinas rectas, filetes de
   1px, etiquetas en versalitas y titulares en sans (sin serif).
   Sitio estático. Sin dependencias externas ni JavaScript.
   1) Variables  2) Base  3) Utilidades  4) Componentes
   5) Secciones  6) Responsive
   ============================================================ */

/* ---------- 1) Variables ---------- */
:root {
  --accent:      #0F5F63;   /* verde petróleo */
  --accent-dark: #0B4749;
  --accent-mid:  #7FC0C2;   /* acento sobre fondo oscuro */
  --accent-tint: #E4EDEC;

  --ink:         #14181B;
  --ink-2:       #3B4349;
  --muted:       #6E767C;

  --paper:       #F6F5F1;
  --surface:     #FFFFFF;
  --line:        #DFDCD4;
  --line-strong: #C8C4B9;

  --dark:        #131719;
  --dark-2:      #1B2124;
  --dark-line:   rgba(255, 255, 255, .14);

  --maxw:        1200px;
  --pad:         clamp(1.25rem, 3vw, 2rem);

  --sans: "Helvetica Neue", Helvetica, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
}

/* ---------- 2) Base ---------- */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16.5px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--sans);
  font-weight: 700;
  line-height: 1.1;
  margin: 0 0 .6em;
  letter-spacing: -.022em;
  color: var(--ink);
}
h1 { font-size: clamp(2.15rem, 1.35rem + 3.2vw, 3.7rem); letter-spacing: -.03em; line-height: 1.04; }
h2 { font-size: clamp(1.5rem, 1.1rem + 1.5vw, 2.25rem); }
h3 { font-size: 1.1rem; margin-bottom: .4rem; }
h4 { font-size: .78rem; letter-spacing: .16em; text-transform: uppercase; margin-bottom: .9rem; }

p { margin: 0 0 1rem; }
a { color: var(--accent-dark); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

img, svg { max-width: 100%; }
img { display: block; }
ul, ol { margin: 0; padding: 0; list-style: none; }
figure { margin: 0; }
dl, dd, dt { margin: 0; }

::selection { background: var(--accent); color: #fff; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

section[id] { scroll-margin-top: 84px; }

/* ---------- 3) Utilidades ---------- */
.container { width: min(var(--maxw), 100% - (var(--pad) * 2)); margin-inline: auto; }

.section { padding: clamp(3.5rem, 7vw, 6.5rem) 0; }

/* Etiqueta de sección: filete corto + versalitas */
.label {
  display: flex; align-items: center; gap: .7rem;
  font-size: .72rem; font-weight: 700; letter-spacing: .19em;
  text-transform: uppercase; color: var(--accent-dark);
  margin: 0 0 1.1rem;
}
.label::before {
  content: ""; width: 30px; height: 1px; background: currentColor; flex: 0 0 30px;
}
.label-light { color: var(--accent-mid); }
.label-num {
  font-weight: 700; color: var(--muted);
  padding-right: .7rem; margin-right: .1rem;
  border-right: 1px solid var(--line-strong);
}

.sec-head { max-width: 62ch; margin-bottom: clamp(2rem, 4vw, 3.25rem); }
.sec-head h2 { margin-bottom: .5rem; }
.sec-sub { color: var(--ink-2); margin: 0; }

/* Botones: rectangulares, texto en versalitas */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .5rem;
  padding: .95rem 1.6rem; border: 1px solid transparent;
  font: inherit; font-size: .78rem; font-weight: 700;
  letter-spacing: .12em; text-transform: uppercase; line-height: 1;
  cursor: pointer;
  transition: background .18s, color .18s, border-color .18s;
}
.btn:hover { text-decoration: none; }
.btn-solid { background: var(--accent); color: #fff; }
.btn-solid:hover { background: var(--accent-dark); }
.btn-line { border-color: rgba(255, 255, 255, .45); color: #fff; }
.btn-line:hover { background: rgba(255, 255, 255, .1); border-color: #fff; }
.btn-sm { padding: .72rem 1.1rem; font-size: .72rem; }
.btn-wide { width: 100%; max-width: 360px; }

/* ---------- 4) Componentes ---------- */
/* Marca */
.brand { display: inline-flex; align-items: center; gap: .8rem; color: var(--ink); }
.brand:hover { text-decoration: none; }
.mark {
  flex: 0 0 42px; width: 42px; height: 42px;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--accent); color: #fff;
  font-size: .72rem; font-weight: 700; letter-spacing: .07em;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-text strong { font-size: 1.05rem; font-weight: 700; letter-spacing: .12em; }
.brand-text small { font-size: .64rem; letter-spacing: .13em; text-transform: uppercase; color: var(--muted); }

/* Aviso */
.notice {
  margin-top: clamp(2rem, 4vw, 3rem);
  padding: 1.15rem 1.5rem;
  border: 1px solid var(--line); border-left: 3px solid var(--accent);
  background: var(--surface);
}
.notice p { margin: 0; color: var(--ink-2); font-size: .94rem; }
.notice a { font-weight: 700; }

/* Lista de verificación */
.checklist-box {
  margin-top: 2.25rem; padding: 1.4rem 1.6rem;
  border: 1px solid var(--line); background: var(--surface);
}
.checklist-box > strong {
  display: block; font-size: .74rem; letter-spacing: .14em;
  text-transform: uppercase; color: var(--ink); margin-bottom: .9rem;
}
.checklist li {
  position: relative; padding-left: 1.6rem; margin-top: .55rem;
  font-size: .94rem; color: var(--ink-2);
}
.checklist li::before {
  content: ""; position: absolute; left: 0; top: .5em;
  width: .68em; height: .68em; background: var(--accent);
}

/* Lista de datos (ficha fiscal) */
.data-list { display: grid; }
.data-list > div { padding: .95rem 0; border-top: 1px solid var(--line); }
.data-list > div:first-child { border-top: 0; padding-top: 0; }
.data-list dt {
  font-size: .7rem; letter-spacing: .14em; text-transform: uppercase;
  color: var(--muted); font-weight: 700; margin-bottom: .25rem;
}
.data-list dd { font-size: .96rem; color: var(--ink-2); }
.fiscal-act li { position: relative; padding-left: 1rem; margin-top: .3rem; }
.fiscal-act li::before {
  content: ""; position: absolute; left: 0; top: .72em;
  width: 5px; height: 1px; background: var(--accent);
}

/* ---------- 5) Secciones ---------- */
/* 顶部信息条 */
.topbar {
  background: var(--dark); color: rgba(255, 255, 255, .72);
  font-size: .76rem; letter-spacing: .06em;
}
.topbar-row {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; min-height: 38px;
}
.topbar-item { margin: 0; }
.topbar a { color: var(--accent-mid); }
.topbar a:hover { color: #fff; }

/* 页眉 */
.masthead {
  position: sticky; top: 0; z-index: 30;
  background: rgba(246, 245, 241, .94);
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.mast-row {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1.5rem; min-height: 76px;
}
.site-nav { display: flex; align-items: center; gap: 2rem; }
.site-nav > a {
  font-size: .78rem; font-weight: 700; letter-spacing: .12em;
  text-transform: uppercase; color: var(--ink-2);
  padding: .35rem 0; border-bottom: 2px solid transparent;
}
.site-nav > a:hover { color: var(--accent); border-bottom-color: var(--accent); text-decoration: none; }
.site-nav .btn { border-bottom: 0; color: #fff; }
.site-nav .btn:hover { color: #fff; }

/* 汉堡按钮（窄屏） */
.nav-toggle { position: absolute; opacity: 0; width: 1px; height: 1px; pointer-events: none; }
.nav-burger { display: none; cursor: pointer; padding: .5rem; }
.nav-burger span { display: block; width: 24px; height: 2px; margin: 5px 0; background: var(--ink); transition: transform .2s, opacity .2s; }

/* 首屏：深色全幅 + 背景图 */
.hero {
  position: relative; color: #fff;
  background-image:
    linear-gradient(102deg, rgba(11, 15, 17, .96) 0%, rgba(11, 15, 17, .88) 46%, rgba(11, 15, 17, .48) 100%),
    linear-gradient(to top, rgba(11, 15, 17, .72) 0%, rgba(11, 15, 17, 0) 46%),
    url("assets/img/hero.jpg");
  background-size: cover;
  background-position: center 40%;
  padding: clamp(3.5rem, 8vw, 6.5rem) 0 0;
}
.hero-inner { max-width: 760px; }
.hero h1 { color: #fff; margin-bottom: 1.15rem; }
.hero .lead {
  color: rgba(255, 255, 255, .84); font-size: 1.04rem;
  max-width: 56ch; margin-bottom: 0;
}
.hero-cta { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 2.25rem; }

/* 首屏数据条 */
.hero-facts { margin-top: clamp(3rem, 7vw, 5.5rem); }
.hero-facts ul {
  display: grid; grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--dark-line);
}
.hero-facts li {
  padding: 1.5rem 0 1.9rem;
  border-left: 1px solid var(--dark-line);
}
.hero-facts li:first-child { border-left: 0; padding-left: 0; }
.hero-facts li + li { padding-left: 1.75rem; }
.hero-facts strong {
  display: block; font-size: 1.5rem; font-weight: 700;
  letter-spacing: -.02em; color: #fff; margin-bottom: .2rem;
}
.hero-facts span {
  font-size: .7rem; letter-spacing: .13em; text-transform: uppercase;
  color: rgba(255, 255, 255, .58);
}

/* 经营范围条 */
.giro {
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  padding: clamp(2rem, 4vw, 2.75rem) 0;
}
.giro .label { margin-bottom: 1.15rem; }
.giro-list {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem 2rem;
}
.giro-list li {
  position: relative; padding-left: 1.15rem;
  font-size: .9rem; font-weight: 700; letter-spacing: .02em; color: var(--ink);
}
.giro-list li::before {
  content: ""; position: absolute; left: 0; top: .62em;
  width: 8px; height: 2px; background: var(--accent);
}

/* 01 · 业务线（编号行） */
.svc { border-top: 1px solid var(--line-strong); }
.svc-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 200px;
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: center;
  padding: 1.85rem 0;
  border-bottom: 1px solid var(--line);
}
.svc-num {
  display: inline-block; width: 3.6rem;
  font-size: 1rem; font-weight: 700; letter-spacing: .1em;
  color: var(--line-strong); transition: color .2s;
}
.svc-copy h3 { margin-bottom: .35rem; }
.svc-copy p { margin: 0; color: var(--ink-2); font-size: .96rem; max-width: 58ch; }
.svc-thumb {
  aspect-ratio: 16 / 11; overflow: hidden; background: var(--line);
}
.svc-thumb img {
  width: 100%; height: 100%; object-fit: cover;
  filter: grayscale(88%) contrast(1.03);
  transition: filter .45s ease, transform .6s cubic-bezier(.2,.7,.2,1);
}
.svc-row:hover .svc-num { color: var(--accent); }
.svc-row:hover .svc-thumb img { filter: grayscale(0%) contrast(1); transform: scale(1.045); }

/* 02 · 工作方式（深色） */
.process {
  background: var(--dark); color: rgba(255, 255, 255, .78);
}
.process h2 { color: #fff; }
.process-grid {
  display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  gap: clamp(2.5rem, 6vw, 5rem); align-items: start;
}
.process-head p { color: rgba(255, 255, 255, .74); max-width: 46ch; }
.process-media {
  margin-top: 2.25rem; aspect-ratio: 16 / 10; overflow: hidden;
}
.process-media img { width: 100%; height: 100%; object-fit: cover; }

.steps { border-left: 1px solid var(--dark-line); }
.steps li {
  position: relative;
  display: grid; grid-template-columns: 56px minmax(0, 1fr); gap: 1.25rem;
  padding: 1.6rem 0 1.6rem 1.75rem;
  border-bottom: 1px solid var(--dark-line);
}
.steps li:first-child { padding-top: .35rem; }
.steps li:last-child { border-bottom: 0; }
.steps li::before {
  content: ""; position: absolute; left: -3px; top: 2.05rem;
  width: 5px; height: 5px; background: var(--accent-mid);
}
.steps li:first-child::before { top: .8rem; }
.step-num {
  font-size: .72rem; font-weight: 700; letter-spacing: .14em;
  color: var(--accent-mid); padding-top: .35rem;
}
.steps h3 { color: #fff; font-size: 1.02rem; margin-bottom: .3rem; }
.steps p { margin: 0; font-size: .93rem; color: rgba(255, 255, 255, .7); }

/* 03 · 联系 */
.contact-grid {
  display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: clamp(2.5rem, 6vw, 5rem); align-items: start;
}
.contact-lead {
  font-size: .74rem; letter-spacing: .14em; text-transform: uppercase;
  color: var(--muted); font-weight: 700; margin: 0 0 .55rem;
}
.mail-display {
  display: block; margin-bottom: 1.6rem;
  font-size: clamp(1.25rem, .8rem + 1.7vw, 2rem); font-weight: 700;
  letter-spacing: -.025em; color: var(--accent-dark); word-break: break-all;
  line-height: 1.15;
}
.mail-display:hover { color: var(--accent); text-decoration: none; }

.fiscal {
  border: 1px solid var(--line); background: var(--surface);
  padding: 1.6rem 1.8rem 1.2rem;
}
.fiscal h3 {
  font-size: .74rem; letter-spacing: .14em; text-transform: uppercase;
  margin-bottom: 1rem; padding-bottom: .9rem; border-bottom: 1px solid var(--line);
}

/* 页脚 */
.site-footer { background: var(--dark); color: rgba(255, 255, 255, .72); padding: 3rem 0 1.5rem; }
.footer-grid {
  display: grid; grid-template-columns: 1.2fr 1fr 1fr;
  gap: clamp(2rem, 5vw, 4rem);
  padding-bottom: 2.5rem; border-bottom: 1px solid var(--dark-line);
}
.footer-brand .mark { margin-bottom: 1.1rem; }
.footer-tag { margin: 0; font-size: .92rem; color: rgba(255, 255, 255, .62); max-width: 34ch; }
.site-footer h4 { color: rgba(255, 255, 255, .55); }
.footer-list li { font-size: .92rem; margin-bottom: .6rem; color: rgba(255, 255, 255, .72); }
.site-footer a { color: var(--accent-mid); }
.site-footer a:hover { color: #fff; }
.footer-bottom {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between;
  gap: .5rem 2rem; padding-top: 1.5rem;
}
.footer-bottom p { margin: 0; font-size: .78rem; letter-spacing: .05em; color: rgba(255, 255, 255, .48); }

/* ---------- 6) Responsive ---------- */
@media (max-width: 980px) {
  /* 导航折叠 */
  .nav-burger { display: block; }
  .site-nav {
    position: absolute; left: 0; right: 0; top: 100%;
    flex-direction: column; align-items: stretch; gap: 0;
    display: none;
    background: var(--paper); border-bottom: 1px solid var(--line);
    padding: .5rem 1.5rem 1.25rem;
  }
  .nav-toggle:checked ~ .site-nav { display: flex; }
  .site-nav > a {
    padding: .95rem 0; border-bottom: 1px solid var(--line);
    font-size: .82rem;
  }
  .site-nav > a:hover { border-bottom-color: var(--line); }
  .site-nav .btn { margin-top: 1rem; border-bottom: 0; align-self: flex-start; }
  .nav-toggle:checked ~ .nav-burger span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .nav-toggle:checked ~ .nav-burger span:nth-child(2) { opacity: 0; }
  .nav-toggle:checked ~ .nav-burger span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

  /* 双栏转单栏 */
  .process-grid, .contact-grid { grid-template-columns: 1fr; }
  .hero-facts ul { grid-template-columns: repeat(2, 1fr); }
  .hero-facts li { padding: 1.25rem 0; }
  .hero-facts li:nth-child(3) { border-left: 0; padding-left: 0; }
  .hero-facts li:nth-child(1), .hero-facts li:nth-child(2) { border-top: 0; }
  .hero-facts li:nth-child(3), .hero-facts li:nth-child(4) { border-top: 1px solid var(--dark-line); }
  .giro-list { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 720px) {
  .topbar-row { flex-direction: column; align-items: flex-start; gap: 0; padding: .5rem 0; }
  .brand-text small { display: none; }
  .hero { background-position: center 30%; }
  .hero-cta .btn { flex: 1 1 100%; }

  /* 业务线行：改为堆叠，图片置顶，编号独立成行 */
  .svc-row { grid-template-columns: 1fr; gap: 1rem; padding: 1.5rem 0 1.75rem; }
  .svc-num {
    display: block; width: auto; margin-bottom: .3rem;
    font-size: .72rem; letter-spacing: .16em; color: var(--muted);
  }
  .svc-thumb { order: -1; aspect-ratio: 16 / 9; }
  .svc-thumb img { filter: grayscale(0%); }

  .steps li { grid-template-columns: 40px minmax(0, 1fr); gap: 1rem; padding-left: 1.25rem; }
  .footer-grid { grid-template-columns: 1fr; gap: 2rem; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}

@media print {
  .topbar, .masthead, .hero-cta, .hero-facts { display: none; }
  body { background: #fff; }
  .hero { color: var(--ink); background-image: none; padding: 0; }
  .hero h1, .hero .lead { color: var(--ink); }
}