/* ========================================
   一道标识官网 — 全局设计系统 V1.0
   Design System for Yidao Signs Official Website
   ======================================== */

/* --- MiSans Font via CDN --- */
@import url('https://cdn.bootcdn.net/ajax/libs/misans-webfont/4.3.1/misans-style.css');

/* --- CSS Custom Properties --- */
:root {
  /* Brand Colors */
  --c-red:         #C41230;
  --c-red-dark:    #8B1A2B;
  --c-red-light:   #E85D75;
  --c-red-bg:      #FDF2F4;

  /* Neutrals */
  --c-white:       #FFFFFF;
  --c-bg:          #FAFAFA;
  --c-bg-alt:      #F2F2F2;
  --c-dark:        #1A1A1A;
  --c-dark-alt:    #2B2B2B;

  /* Text */
  --c-text:        #222222;
  --c-text-body:   #444444;
  --c-text-muted:  #777777;
  --c-text-light:  #AAAAAA;

  /* Accent */
  --c-gold:        #C8A45C;

  /* Typography Scale */
  --fs-display:    clamp(2.5rem, 5vw, 4rem);    /* 64px */
  --fs-h1:         clamp(2rem, 4vw, 3rem);       /* 48px */
  --fs-h2:         clamp(1.6rem, 3vw, 2.25rem);  /* 36px */
  --fs-h3:         1.5rem;                         /* 24px */
  --fs-h4:         1.25rem;                        /* 20px */
  --fs-body:       1rem;                           /* 16px */
  --fs-body-sm:    0.9375rem;                      /* 15px */
  --fs-small:      0.875rem;                       /* 14px */
  --fs-caption:    0.8125rem;                      /* 13px */
  --fs-number:     clamp(2.2rem, 4.5vw, 3.5rem);  /* 56px */

  /* Font Family */
  --ff-body:       "MiSans", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  --ff-number:     "MiSans", "PingFang SC", "Helvetica Neue", sans-serif;

  /* Spacing Scale (8px grid) */
  --sp-xxs:        4px;
  --sp-xs:         8px;
  --sp-sm:         12px;
  --sp-md:         24px;
  --sp-lg:         40px;
  --sp-xl:         64px;
  --sp-2xl:        80px;
  --sp-3xl:        120px;

  /* Layout */
  --max-width:     1240px;
  --content-width: 1200px;
  --nav-height:    72px;

  /* Borders & Radius */
  --radius-sm:     4px;
  --radius-md:     8px;
  --radius-lg:     12px;
  --radius-xl:     16px;
  --border-color:  #E5E5E5;

  /* Shadows */
  --shadow-sm:     0 1px 3px rgba(0,0,0,0.06);
  --shadow-md:     0 4px 16px rgba(0,0,0,0.08);
  --shadow-lg:     0 12px 40px rgba(0,0,0,0.10);
  --shadow-card:   0 2px 12px rgba(0,0,0,0.05);

  /* Transitions */
  --ease:          cubic-bezier(0.25, 0.1, 0.25, 1);
  --ease-spring:   cubic-bezier(0.34, 1.56, 0.64, 1);
  --dur-fast:      150ms;
  --dur-base:      300ms;
  --dur-slow:      500ms;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--ff-body);
  font-size: var(--fs-body);
  line-height: 1.75;
  color: var(--c-text-body);
  background: var(--c-white);
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease);
}

ul, ol {
  list-style: none;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--sp-md);
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--ff-body);
  color: var(--c-text);
  line-height: 1.3;
  font-weight: 500;
}

h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }
h4 { font-size: var(--fs-h4); }

.section-label {
  font-size: var(--fs-small);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--c-white);
  font-weight: 500;
  margin-bottom: var(--sp-sm);
  display: inline-block;
  background: var(--c-red);
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  line-height: 1.4;
}

.section-title {
  font-size: var(--fs-h2);
  font-weight: 600;
  color: var(--c-text);
  margin-bottom: var(--sp-sm);
}

.section-subtitle {
  font-size: var(--fs-body);
  color: var(--c-text-muted);
  max-width: 600px;
  line-height: 1.8;
}

.section-header {
  text-align: center;
  margin-bottom: var(--sp-2xl);
}

.section-header .section-subtitle {
  margin: 0 auto;
}

.section-header.left {
  text-align: left;
}

.section-header.left .section-subtitle {
  margin: 0;
}

/* --- Grid System (12 columns) --- */
.grid {
  display: grid;
  gap: var(--sp-md);
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-5 { grid-template-columns: repeat(5, 1fr); }
.grid-6 { grid-template-columns: repeat(6, 1fr); }

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-xs);
  padding: 14px 36px;
  font-size: var(--fs-body-sm);
  font-weight: 500;
  font-family: var(--ff-body);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--dur-base) var(--ease);
  white-space: nowrap;
  letter-spacing: 0.02em;
}

.btn-primary {
  background: var(--c-red);
  color: var(--c-white);
}

.btn-primary:hover {
  background: var(--c-red-dark);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(196,18,48,0.3);
}

.btn-outline {
  background: transparent;
  color: var(--c-text);
  border: 1.5px solid #D0D0D0;
}

.btn-outline:hover {
  border-color: var(--c-red);
  color: var(--c-red);
  transform: translateY(-1px);
}

.btn-white {
  background: var(--c-white);
  color: var(--c-red);
}

.btn-white:hover {
  background: var(--c-bg);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.1);
}

.btn-dark {
  background: var(--c-dark);
  color: var(--c-white);
}

.btn-dark:hover {
  background: var(--c-dark-alt);
}

.btn-lg {
  padding: 18px 48px;
  font-size: var(--fs-body);
}

.btn-sm {
  padding: 10px 24px;
  font-size: var(--fs-small);
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  z-index: 1000;
  border-bottom: 1px solid transparent;
  transition: all var(--dur-base) var(--ease);
}

.nav.scrolled {
  border-bottom-color: #EEEEEE;
  box-shadow: 0 1px 8px rgba(0,0,0,0.04);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--sp-md);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--sp-sm);
  font-size: var(--fs-h4);
  font-weight: 600;
  color: var(--c-text);
  letter-spacing: -0.02em;
}

.nav-logo img {
  height: 36px;
  width: auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--sp-lg);
}

.nav-links a {
  font-size: var(--fs-body-sm);
  color: var(--c-text-body);
  position: relative;
  padding: var(--sp-xs) 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--c-red);
  transition: width var(--dur-base) var(--ease);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--c-red);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

/* --- Hero Section --- */
.hero {
  position: relative;
  width: 100%;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  margin-top: 0;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.hero-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(0,0,0,0.45) 0%,
    rgba(0,0,0,0.25) 50%,
    rgba(0,0,0,0.55) 100%
  );
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--sp-3xl) var(--sp-md);
  color: var(--c-white);
}

.hero-content .section-label {
  color: var(--c-white);
  font-size: var(--fs-small);
  letter-spacing: 0.12em;
  margin-bottom: var(--sp-md);
  display: inline-block;
  background: var(--c-red);
  padding: 6px 16px;
  border-radius: var(--radius-sm);
}

.hero-content h1 {
  font-size: var(--fs-display);
  font-weight: 600;
  line-height: 1.15;
  max-width: 720px;
  margin-bottom: var(--sp-md);
  color: var(--c-white);
  letter-spacing: -0.02em;
}

.hero-content .hero-subtitle {
  font-size: var(--fs-h4);
  color: rgba(255,255,255,0.8);
  max-width: 560px;
  line-height: 1.6;
  margin-bottom: var(--sp-lg);
  font-weight: 400;
}

.hero-actions {
  display: flex;
  gap: var(--sp-md);
  flex-wrap: wrap;
}

/* --- Section Spacing --- */
.section {
  padding: var(--sp-3xl) 0;
}

.section-tight {
  padding: var(--sp-2xl) 0;
}

.section-dark {
  background: var(--c-dark);
  color: var(--c-white);
}

.section-dark .section-label {
  color: var(--c-white);
  background: var(--c-red);
}

.section-dark .section-title {
  color: var(--c-white);
}

.section-dark .section-subtitle {
  color: rgba(255,255,255,0.55);
}

.section-alt {
  background: var(--c-bg);
}

/* --- Stats / Numbers --- */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: var(--sp-md);
  text-align: center;
}

.stat-item {
  padding: var(--sp-lg) var(--sp-md);
}

.stat-number {
  font-size: var(--fs-number);
  font-weight: 600;
  color: var(--c-red);
  line-height: 1.1;
  margin-bottom: var(--sp-xs);
  font-family: var(--ff-number);
  white-space: nowrap;
}

.stat-number .unit {
  font-size: 0.4em;
  font-weight: 500;
  margin-left: 2px;
}

.stat-label {
  font-size: var(--fs-small);
  color: var(--c-text-muted);
  line-height: 1.5;
}

.section-dark .stat-number {
  color: var(--c-white);
}

.section-dark .stat-label {
  color: rgba(255,255,255,0.55);
}

/* --- Cards --- */
.card {
  background: var(--c-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--dur-base) var(--ease);
  border: 1px solid var(--border-color);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: transparent;
}

.card-img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background: var(--c-bg-alt);
}

.card-body {
  padding: var(--sp-md);
}

.card-title {
  font-size: var(--fs-h4);
  font-weight: 600;
  margin-bottom: var(--sp-xs);
  color: var(--c-text);
}

.card-text {
  font-size: var(--fs-body-sm);
  color: var(--c-text-muted);
  line-height: 1.7;
}

.card-tag {
  display: inline-block;
  font-size: var(--fs-caption);
  color: var(--c-red);
  background: var(--c-red-bg);
  padding: 2px 10px;
  border-radius: 100px;
  margin-bottom: var(--sp-sm);
}

/* --- Icon Cards --- */
.icon-card {
  text-align: center;
  padding: var(--sp-xl) var(--sp-md);
  background: var(--c-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  transition: all var(--dur-base) var(--ease);
}

.icon-card:hover {
  border-color: var(--c-red);
  box-shadow: var(--shadow-md);
}

.icon-card-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--sp-md);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--c-red-bg);
  border-radius: var(--radius-md);
  font-size: 28px;
  color: var(--c-red);
}

.icon-card-title {
  font-size: var(--fs-h4);
  font-weight: 600;
  margin-bottom: var(--sp-xs);
  color: var(--c-text);
}

.icon-card-text {
  font-size: var(--fs-body-sm);
  color: var(--c-text-muted);
  line-height: 1.7;
}

/* Dark bg icon cards */
.section-dark .icon-card {
  background: rgba(255,255,255,0.05);
  border-color: rgba(255,255,255,0.1);
}

.section-dark .icon-card:hover {
  background: rgba(255,255,255,0.08);
  border-color: var(--c-red);
}

.section-dark .icon-card-title { color: var(--c-white); }
.section-dark .icon-card-text { color: rgba(255,255,255,0.55); }

/* --- Solution Cards --- */
.solution-card {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  aspect-ratio: 3 / 2;
  cursor: pointer;
  display: flex;
  align-items: flex-end;
}

.solution-card img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--dur-slow) var(--ease);
}

.solution-card::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(0deg, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0.1) 50%);
  z-index: 1;
}

.solution-card:hover img {
  transform: scale(1.05);
}

.solution-card-info {
  position: relative;
  z-index: 2;
  padding: var(--sp-lg);
  color: var(--c-white);
}

.solution-card-info h3 {
  font-size: var(--fs-h3);
  font-weight: 600;
  margin-bottom: var(--sp-xs);
  color: var(--c-white);
}

.solution-card-info p {
  font-size: var(--fs-body-sm);
  opacity: 0.8;
  line-height: 1.6;
}

/* --- Process / Timeline --- */
.process-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp-md);
  position: relative;
}

.process-step {
  text-align: center;
  padding: var(--sp-lg) var(--sp-md);
  position: relative;
}

.process-number {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--c-red);
  color: var(--c-white);
  font-size: var(--fs-h3);
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--sp-md);
  line-height: 1;
}

.process-title {
  font-size: var(--fs-h4);
  font-weight: 600;
  margin-bottom: var(--sp-xs);
}

.process-text {
  font-size: var(--fs-body-sm);
  color: var(--c-text-muted);
  line-height: 1.7;
}

.process-arrow {
  position: absolute;
  top: 28px;
  right: -12px;
  color: var(--c-text-light);
  font-size: var(--fs-h3);
  z-index: 1;
}

/* --- Case Showcase --- */
.case-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--sp-md);
}

.case-card {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  aspect-ratio: 4 / 3;
  cursor: pointer;
}

.case-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--dur-slow) var(--ease);
}

.case-card::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(0deg, rgba(0,0,0,0.6) 0%, transparent 40%);
  opacity: 0;
  transition: opacity var(--dur-base) var(--ease);
}

.case-card:hover::after {
  opacity: 1;
}

.case-card:hover img {
  transform: scale(1.05);
}

.case-card-info {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: var(--sp-md);
  z-index: 1;
  color: var(--c-white);
  opacity: 0;
  transform: translateY(10px);
  transition: all var(--dur-base) var(--ease);
}

.case-card:hover .case-card-info {
  opacity: 1;
  transform: translateY(0);
}

.case-card-info h4 {
  color: var(--c-white);
  font-size: var(--fs-body);
  font-weight: 500;
}

.case-card-info span {
  font-size: var(--fs-caption);
  opacity: 0.7;
}

/* --- CTA Banner --- */
.cta-banner {
  background: linear-gradient(135deg, var(--c-red) 0%, var(--c-red-dark) 100%);
  border-radius: var(--radius-xl);
  padding: var(--sp-2xl) var(--sp-xl);
  text-align: center;
  color: var(--c-white);
}

.cta-banner h2 {
  color: var(--c-white);
  font-size: var(--fs-h2);
  margin-bottom: var(--sp-sm);
}

.cta-banner p {
  color: rgba(255,255,255,0.8);
  font-size: var(--fs-body);
  max-width: 560px;
  margin: 0 auto var(--sp-lg);
  line-height: 1.8;
}

/* --- Footer --- */
.footer {
  background: var(--c-dark);
  color: rgba(255,255,255,0.55);
  padding: var(--sp-2xl) 0 var(--sp-lg);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: var(--sp-xl);
  margin-bottom: var(--sp-xl);
}

.footer-brand h3 {
  color: var(--c-white);
  font-size: var(--fs-h3);
  font-weight: 600;
  margin-bottom: var(--sp-sm);
}

.footer-logo {
  height: 40px;
  width: auto;
  margin-bottom: var(--sp-sm);
  display: block;
}

.footer-brand p {
  font-size: var(--fs-body-sm);
  line-height: 1.8;
  margin-bottom: var(--sp-md);
}

.footer h4 {
  color: var(--c-white);
  font-size: var(--fs-body);
  font-weight: 500;
  margin-bottom: var(--sp-md);
}

.footer-links a {
  display: block;
  font-size: var(--fs-body-sm);
  color: rgba(255,255,255,0.45);
  padding: var(--sp-xxs) 0;
  transition: color var(--dur-fast) var(--ease);
}

.footer-links a:hover {
  color: var(--c-white);
}

.footer-contact-item {
  display: flex;
  gap: var(--sp-sm);
  font-size: var(--fs-body-sm);
  margin-bottom: var(--sp-sm);
  align-items: flex-start;
}

.footer-contact-item .icon {
  color: rgba(255,255,255,0.6);
  flex-shrink: 0;
  margin-top: 2px;
}

.footer-bottom {
  padding-top: var(--sp-md);
  border-top: 1px solid rgba(255,255,255,0.08);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--fs-caption);
  color: rgba(255,255,255,0.3);
}

/* --- Contact Form --- */
.form-group {
  margin-bottom: var(--sp-md);
}

.form-label {
  display: block;
  font-size: var(--fs-small);
  font-weight: 500;
  color: var(--c-text);
  margin-bottom: var(--sp-xs);
}

.form-label .required {
  color: var(--c-red);
  margin-left: 2px;
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: 14px 16px;
  font-size: var(--fs-body-sm);
  font-family: var(--ff-body);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-sm);
  background: var(--c-white);
  color: var(--c-text);
  transition: all var(--dur-fast) var(--ease);
  outline: none;
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  border-color: var(--c-red);
  box-shadow: 0 0 0 3px rgba(196,18,48,0.08);
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--c-text-light);
}

.form-textarea {
  min-height: 120px;
  resize: vertical;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-md);
}

/* --- Page Hero (sub pages) --- */
.page-hero {
  padding-top: calc(var(--nav-height) + var(--sp-2xl));
  padding-bottom: var(--sp-2xl);
  background: var(--c-bg);
  text-align: center;
}

.page-hero h1 {
  margin-bottom: var(--sp-sm);
  font-weight: 700;
}

.page-hero .breadcrumb {
  font-size: var(--fs-small);
  color: var(--c-text-muted);
}

.page-hero .breadcrumb a {
  color: var(--c-text-muted);
}

.page-hero .breadcrumb a:hover {
  color: var(--c-red);
}

.page-hero .breadcrumb span {
  margin: 0 var(--sp-xs);
}

/* --- Feature with Image --- */
.feature-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-2xl);
  align-items: center;
}

.feature-row.reverse {
  direction: rtl;
}

.feature-row.reverse .feature-content {
  direction: ltr;
}

.feature-img {
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.feature-img img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

/* Home about intro: balance image vs text weight */
.about-section .feature-row {
  grid-template-columns: 5fr 7fr;
  align-items: stretch;
}

.about-section .feature-img {
  align-self: stretch;
  display: flex;
}

.about-section .feature-img img {
  height: 100%;
  aspect-ratio: auto;
  object-fit: cover;
  object-position: center;
}

.about-section .feature-content {
  display: flex;
  flex-direction: column;
}

.about-section .section-label {
  align-self: flex-start;
}

.about-section .btn-outline {
  align-self: flex-start;
  padding: 10px 28px;
  font-size: var(--fs-small);
  margin-top: auto;
}

.feature-content h2 {
  margin-bottom: var(--sp-sm);
}

.feature-content .lead {
  font-size: var(--fs-body);
  color: var(--c-text-muted);
  line-height: 1.8;
  margin-bottom: var(--sp-md);
}

.feature-list {
  display: grid;
  gap: var(--sp-md);
}

.feature-list-item {
  display: flex;
  gap: var(--sp-sm);
  align-items: flex-start;
}

.feature-list-item .check {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--c-red-bg);
  color: var(--c-red);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 12px;
  margin-top: 2px;
}

.feature-list-item .text h4 {
  font-size: var(--fs-body);
  font-weight: 500;
  margin-bottom: 2px;
}

.feature-list-item .text p {
  font-size: var(--fs-body-sm);
  color: var(--c-text-muted);
}

/* --- Article Cards --- */
.article-card {
  display: flex;
  gap: var(--sp-md);
  padding: var(--sp-md) 0;
  border-bottom: 1px solid var(--border-color);
  cursor: pointer;
  transition: all var(--dur-fast) var(--ease);
}

.article-card:hover {
  border-bottom-color: var(--c-red);
}

.article-card:hover h4 {
  color: var(--c-red);
}

.article-card-img {
  display: block;
  width: 200px;
  height: 140px;
  border-radius: var(--radius-md);
  object-fit: cover;
  flex-shrink: 0;
  background: var(--c-bg-alt);
  overflow: hidden;
}

.article-card-content {
  flex: 1;
}

.article-card-meta {
  font-size: var(--fs-caption);
  color: var(--c-text-light);
  margin-bottom: var(--sp-xs);
}

.article-card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: var(--radius-md);
}

.article-card-content .title-link {
  text-decoration: none;
  color: inherit;
}

.article-card .read-more {
  color: var(--c-red);
  font-weight: 500;
  font-size: var(--fs-body-sm);
  text-decoration: none;
}

.article-card-content h4 {
  font-size: var(--fs-h4);
  font-weight: 700;
  margin-bottom: var(--sp-xs);
  transition: color var(--dur-fast) var(--ease);
}

.article-card-content p {
  font-size: var(--fs-body-sm);
  color: var(--c-text-muted);
  line-height: 1.7;
}

/* --- Article Detail Body --- */
/* ===== 文章排版层级规范 v1.1 =====
   ① H1 主标题(hero) ② 副题(hero) ③ 元信息 ④ 导读摘要
   ⑤ H2 章节标题     ⑥ 正文      ⑦ 备注(图注/标签)  */
.article-body { max-width: 680px; margin: 0 auto; }

/* ③ 元信息（hero 内：日期 · 阅读时长） */
.article-meta {
  display: flex;
  gap: var(--sp-md);
  justify-content: center;
  margin-top: var(--sp-sm);
  font-size: var(--fs-caption);
  color: var(--c-text-light);
  letter-spacing: 0.04em;
}

/* hero 副题 */
.article-deck {
  font-size: 1.0625rem;
  color: var(--c-text-muted);
  margin-top: var(--sp-xs);
}

/* ④ 导读摘要 — 全文唯一，红线+浅红底 */
.article-summary {
  font-size: 1.125rem;
  line-height: 1.8;
  color: var(--c-text-body);
  background: var(--c-red-bg);
  border-left: 3px solid var(--c-red);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: var(--sp-md) var(--sp-md);
  margin-bottom: var(--sp-xl);
}

/* ⑤ H2 章节标题 — 红色工程序号 + 加粗标题 */
.article-body h2 {
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--c-text);
  line-height: 1.4;
  margin: var(--sp-xl) 0 var(--sp-md);
  display: flex;
  align-items: baseline;
  gap: var(--sp-sm);
}
/* 章节内小标题（如需要） */
.article-body h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--c-text);
  margin: var(--sp-lg) 0 var(--sp-sm);
}

/* ⑥ 正文 */
.article-body p { font-size: var(--fs-body); line-height: 1.85; color: var(--c-text-body); margin-bottom: var(--sp-md); }
.article-body ul { margin-bottom: var(--sp-md); padding-left: 1.4em; }
.article-body ul li { font-size: var(--fs-body); line-height: 1.85; color: var(--c-text-body); margin-bottom: var(--sp-xs); }

/* 金句块引 — 深色卡片，与摘要、公司卡片区分 */
.article-body blockquote {
  margin: var(--sp-xl) 0;
  padding: var(--sp-md) var(--sp-lg);
  background: var(--c-dark);
  border-radius: var(--radius-md);
}
.article-body blockquote p {
  margin: 0;
  color: rgba(255,255,255,0.92);
  font-size: 1.0625rem;
  line-height: 1.9;
}

/* ⑦ 备注层：图注 */
.article-body .article-figure figcaption,
.article-figure figcaption {
  padding: var(--sp-sm) var(--sp-md);
  font-size: var(--fs-caption);
  color: var(--c-text-muted);
  background: transparent;
  text-align: center;
  line-height: 1.6;
}

/* 文末：关于一道标识 卡片 */
.article-about {
  margin-top: var(--sp-xl);
  padding: var(--sp-md) var(--sp-lg);
  background: var(--c-bg-alt);
  border-radius: var(--radius-md);
}
.article-about .about-label {
  display: block;
  font-size: var(--fs-caption);
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--c-red);
  margin-bottom: var(--sp-xs);
}
.article-about p {
  margin: 0;
  font-size: var(--fs-body-sm);
  line-height: 1.8;
  color: var(--c-text-body);
}

/* ⑦ 备注层：标签 */
.article-tags {
  margin-top: var(--sp-xl);
  padding-top: var(--sp-md);
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-xs);
}
.article-tags span {
  display: inline-block;
  padding: 4px 12px;
  background: var(--c-bg-alt);
  border-radius: 20px;
  font-size: var(--fs-caption);
  color: var(--c-text-muted);
}

.article-back {
  margin-top: var(--sp-lg);
  text-align: center;
}

/* --- Tab Filter --- */
.tab-filters {
  display: flex;
  justify-content: center;
  gap: var(--sp-xs);
  margin-bottom: var(--sp-xl);
  flex-wrap: wrap;
}

.tab-btn {
  padding: 10px 24px;
  border: none;
  background: transparent;
  font-size: var(--fs-body-sm);
  font-family: var(--ff-body);
  color: var(--c-text-muted);
  border-radius: 100px;
  cursor: pointer;
  transition: all var(--dur-fast) var(--ease);
}

.tab-btn:hover {
  color: var(--c-red);
  background: var(--c-red-bg);
}

.tab-btn.active {
  background: var(--c-red);
  color: var(--c-white);
}

/* --- Contact Layout --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-2xl);
}

.contact-info-card {
  padding: var(--sp-lg);
  background: var(--c-bg);
  border-radius: var(--radius-lg);
  margin-bottom: var(--sp-md);
}

.contact-info-card h4 {
  margin-bottom: var(--sp-sm);
}

.contact-info-item {
  display: flex;
  gap: var(--sp-sm);
  align-items: flex-start;
  margin-bottom: var(--sp-sm);
  font-size: var(--fs-body-sm);
}

.contact-info-item .icon {
  width: 40px;
  height: 40px;
  background: var(--c-red-bg);
  color: var(--c-red);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

/* --- Map Placeholder --- */
.map-placeholder {
  width: 100%;
  height: 280px;
  border-radius: var(--radius-lg);
  background: var(--c-bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--c-text-light);
  font-size: var(--fs-small);
  border: 1px dashed var(--border-color);
  margin-top: var(--sp-md);
}

/* --- Certificate Grid --- */
.cert-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp-md);
}

.cert-grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.cert-item {
  text-align: center;
  padding: var(--sp-lg) var(--sp-md);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background: var(--c-white);
}

.cert-item .cert-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto var(--sp-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--c-primary);
}

.cert-item h4 {
  font-size: var(--fs-small);
  font-weight: 500;
  margin-bottom: 4px;
}

.cert-item p {
  font-size: var(--fs-caption);
  color: var(--c-text-muted);
}

/* --- Cert Subsection --- */
.cert-subsection {
  margin-bottom: var(--sp-2xl);
}

.cert-subsection:last-child {
  margin-bottom: 0;
}

.cert-subsection h3 {
  font-size: var(--fs-h4);
  font-weight: 500;
  margin-bottom: var(--sp-md);
  color: var(--c-primary);
  display: flex;
  align-items: center;
  gap: var(--sp-xs);
}

.cert-subsection h3::before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 20px;
  background: var(--c-primary);
  border-radius: 2px;
}

/* --- Placeholder --- */
.placeholder-img {
  background: var(--c-bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  color: var(--c-text-light);
  font-size: var(--fs-small);
  border-radius: inherit;
  min-height: 200px;
}

.placeholder-img .placeholder-label {
  font-size: var(--fs-caption);
  color: var(--c-text-light);
  margin-top: var(--sp-xs);
  background: #F0F0F0;
  padding: 2px 12px;
  border-radius: 100px;
}

/* --- SVG Icons (inline) --- */
.icon-svg {
  width: 24px;
  height: 24px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* --- Animations --- */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-fade-up {
  animation: fadeUp var(--dur-slow) var(--ease) both;
}

.stagger-1 { animation-delay: 0.1s; }
.stagger-2 { animation-delay: 0.2s; }
.stagger-3 { animation-delay: 0.3s; }
.stagger-4 { animation-delay: 0.4s; }
.stagger-5 { animation-delay: 0.5s; }
.stagger-6 { animation-delay: 0.6s; }

/* --- Responsive --- */
@media (max-width: 1024px) {
  :root {
    --sp-3xl: 80px;
    --sp-2xl: 60px;
    --sp-xl: 40px;
  }
  .stats-grid { grid-template-columns: repeat(3, 1fr); }
  .grid-4, .grid-5, .process-grid { grid-template-columns: repeat(2, 1fr); }
  .case-grid { grid-template-columns: repeat(2, 1fr); }
  .cert-grid { grid-template-columns: repeat(2, 1fr); }
  .cert-grid-3 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: var(--sp-lg); }
  .contact-grid { grid-template-columns: 1fr; gap: var(--sp-xl); }
  .feature-row {
    grid-template-columns: 1fr;
    gap: var(--sp-xl);
  }
  .feature-row.reverse { direction: ltr; }
  /* Override about-section's 5fr/7fr for tablet */
  .about-section .feature-row {
    grid-template-columns: 1fr;
  }
  .nav-links { gap: var(--sp-md); }
}

@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
    --sp-3xl: 48px;
    --sp-2xl: 36px;
    --sp-xl: 28px;
    --sp-lg: 20px;
    --sp-md: 16px;
  }

  /* Container tighter padding */
  .container {
    padding: 0 var(--sp-md);
  }

  /* All grids to single column */
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: var(--sp-sm); }
  .grid-2, .grid-3, .grid-4, .grid-5, .grid-6 { grid-template-columns: 1fr; }
  .process-grid { grid-template-columns: 1fr; }
  .case-grid { grid-template-columns: 1fr; }
  .cert-grid, .cert-grid-3 { grid-template-columns: repeat(2, 1fr); }
  .form-row { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: var(--sp-lg); }
  .img-grid-2 { grid-template-columns: 1fr; }

  /* Override about-section's 5fr/7fr for mobile */
  .about-section .feature-row {
    grid-template-columns: 1fr;
  }

  /* Hero adjustments */
  .hero { min-height: 90vh; }
  .hero-content {
    padding: calc(var(--nav-height) + var(--sp-2xl)) var(--sp-md) var(--sp-2xl);
  }
  .hero-content h1 { font-size: 1.75rem; line-height: 1.25; }
  .hero-content .hero-subtitle { font-size: var(--fs-body-sm); margin-bottom: var(--sp-md); }
  .hero-actions {
    flex-direction: column;
    gap: var(--sp-sm);
  }
  .hero-actions .btn {
    width: 100%;
    flex: 1;
    min-width: 0;
    padding: 12px 20px;
    font-size: var(--fs-body-sm);
  }
  .hero-actions .btn-lg { padding: 12px 20px; font-size: var(--fs-body-sm); }

  /* Page hero */
  .page-hero {
    padding-top: calc(var(--nav-height) + var(--sp-xl));
    padding-bottom: var(--sp-xl);
  }
  .page-hero h1 { font-size: 1.5rem; }

  /* Section spacing tighter */
  .section { padding: var(--sp-2xl) 0; }
  .section-tight { padding: var(--sp-xl) 0; }
  .section-header { margin-bottom: var(--sp-xl); }

  /* Typography */
  h2 { font-size: 1.375rem; }
  h3 { font-size: 1.25rem; }
  .section-title { font-size: 1.375rem; }
  .section-subtitle { font-size: var(--fs-body-sm); }

  /* Stats: smaller numbers */
  .stat-item { padding: var(--sp-sm) var(--sp-xs); }
  .stat-number { font-size: 1.75rem; }

  /* Process: hide arrows, tighten */
  .process-arrow { display: none; }
  .process-step { padding: var(--sp-md); }
  .process-number { width: 44px; height: 44px; font-size: 1.125rem; }

  /* Article cards: stack vertically */
  .article-card {
    flex-direction: column;
    gap: var(--sp-sm);
  }
  .article-card-img {
    width: 100%;
    height: 180px;
  }

  /* Article body */
  .article-body { padding: 0 var(--sp-xs); }
  .article-body h2 { font-size: 1.1875rem; }
  .article-body p { font-size: var(--fs-body-sm); }
  .article-summary { font-size: var(--fs-body); padding: var(--sp-md); }

  /* Cards: reduce padding */
  .card-body { padding: var(--sp-md); }
  .icon-card { padding: var(--sp-lg) var(--sp-sm); }
  .icon-card-icon { width: 48px; height: 48px; }

  /* Solution cards: better aspect on mobile */
  .solution-card { aspect-ratio: 16 / 10; }
  .solution-card-info { padding: var(--sp-md); }
  .solution-card-info h3 { font-size: 1.125rem; }

  /* CTA & Mission: tighter padding */
  .cta-banner { padding: var(--sp-xl) var(--sp-md); }
  .cta-banner h2 { font-size: 1.25rem; }
  .mission-banner { padding: var(--sp-xl) var(--sp-md); }
  .mission-text { font-size: 1.1875rem; }

  /* Footer */
  .footer { padding: var(--sp-xl) 0 var(--sp-md); }
  .footer-bottom { flex-direction: column; gap: var(--sp-sm); text-align: center; }

  /* Contact: stack map under info */
  #map { min-height: 280px; }

  /* Buttons */
  .btn { padding: 12px 24px; font-size: var(--fs-body-sm); }
  .btn-lg { padding: 14px 32px; }

  /* Mobile Navigation */
  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--c-white);
    flex-direction: column;
    padding: var(--sp-sm) var(--sp-md);
    box-shadow: var(--shadow-lg);
    gap: 0;
    max-height: calc(100vh - var(--nav-height));
    overflow-y: auto;
    border-top: 1px solid var(--border-color);
  }

  .nav-links.active { display: flex; }
  .nav-links a {
    padding: var(--sp-sm) 0;
    border-bottom: 1px solid var(--border-color);
    font-size: var(--fs-body);
  }
  .nav-links a:last-child { border-bottom: none; }
  .nav-links a::after { display: none; }

  /* Hamburger toggle */
  .nav-toggle {
    display: flex;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: var(--sp-xs);
    z-index: 1001;
  }

  .nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--c-text);
    transition: all var(--dur-base) var(--ease);
    transform-origin: center;
  }

  .nav-toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  .nav-toggle.active span:nth-child(2) {
    opacity: 0;
  }
  .nav-toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  /* Nav logo smaller */
  .nav-logo img { height: 30px; }

  /* Solution nav: scrollable pills */
  .solution-nav { top: var(--nav-height); }
  .solution-nav-inner { padding: var(--sp-xs) var(--sp-md); }
}

@media (min-width: 769px) {
  .nav-toggle { display: none; }
}

/* --- Article Inline Images & Placeholders --- */
.article-figure {
  margin: var(--sp-lg) 0;
  border-radius: var(--radius-md);
  overflow: hidden;
}

.article-figure img {
  width: 100%;
  display: block;
  border-radius: var(--radius-md);
}

.article-figure figcaption {
  padding: var(--sp-sm) var(--sp-md);
  font-size: var(--fs-small);
  color: var(--c-text-muted);
  background: var(--c-bg-alt);
  text-align: center;
  line-height: 1.6;
}

/* Color-block placeholder for planned images — 品牌淡色四色系 v1.1 */
.img-placeholder {
  width: 100%;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-md);
  border: 1px dashed transparent;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--sp-lg) var(--sp-md) var(--sp-md);
  position: relative;
}

.img-placeholder .ph-tag {
  position: absolute;
  top: 12px;
  left: 12px;
  font-size: var(--fs-caption);
  font-weight: 600;
  letter-spacing: 0.06em;
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  color: #fff;
  background: var(--c-red);
}

.img-placeholder .ph-desc {
  font-size: var(--fs-small);
  line-height: 1.7;
  max-width: 480px;
}

/* 四色淡色区分（一道红 / 金 / 蓝 / 灰） */
.img-placeholder.tone-red  { background: #FDF2F4; border-color: #E6B7C1; }
.img-placeholder.tone-red  .ph-desc { color: #8B1A2B; }
.img-placeholder.tone-gold { background: #FAF5EA; border-color: #DFCFA8; }
.img-placeholder.tone-gold .ph-desc { color: #7A6234; }
.img-placeholder.tone-blue { background: #EEF4F9; border-color: #B7CDDD; }
.img-placeholder.tone-blue .ph-desc { color: #1A3A5C; }
.img-placeholder.tone-gray { background: #F2F3F5; border-color: #CFD3D8; }
.img-placeholder.tone-gray .ph-desc { color: #4A4F55; }

/* Two-column image grid for comparison figures */
.img-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-md);
  margin: var(--sp-lg) 0;
}

.img-grid-2 .article-figure {
  margin: 0;
}

/* Article cover hero */
.article-hero-img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: var(--radius-md);
  display: block;
  margin-bottom: var(--sp-xl);
}

/* --- Print --- */
@media print {
  .nav, .footer { display: none; }
}

/* --- Client Wall --- */
.client-wall {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: var(--sp-md);
}

.client-logo {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1 / 1;
  background: var(--c-dark-alt);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--dur-base) var(--ease);
}

.client-logo img {
  max-width: 72%;
  max-height: 72%;
  width: auto;
  height: auto;
  object-fit: contain;
  filter: brightness(0) invert(1); /* ensure white display */
}

.client-logo:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(196,18,48,0.15), 0 2px 8px rgba(0,0,0,0.12);
}

/* --- Mission Banner --- */
.mission-banner {
  text-align: center;
  padding: var(--sp-2xl) var(--sp-xl);
  background: var(--c-dark);
  border-radius: var(--radius-xl);
  color: var(--c-white);
}

.mission-banner .section-label {
  color: var(--c-white);
  background: var(--c-red);
}

.mission-text {
  font-size: var(--fs-h2);
  font-weight: 600;
  color: var(--c-white);
  line-height: 1.5;
  max-width: 820px;
  margin: 0 auto var(--sp-md);
}

.mission-sub {
  font-size: var(--fs-body);
  color: rgba(255,255,255,0.6);
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.8;
}

/* --- Client Wall & Mission Responsive --- */
@media (max-width: 1200px) {
  .client-wall { grid-template-columns: repeat(5, 1fr); }
}
@media (max-width: 1024px) {
  .client-wall { grid-template-columns: repeat(4, 1fr); }
}

@media (max-width: 768px) {
  .client-wall { grid-template-columns: repeat(3, 1fr); }
  .mission-text { font-size: var(--fs-h3); }
}

@media (max-width: 480px) {
  :root {
    --sp-3xl: 36px;
    --sp-2xl: 28px;
    --sp-xl: 20px;
  }

  .container { padding: 0 14px; }

  /* Stats: single column on very small screens */
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: var(--sp-xs); }
  .stat-number { font-size: 1.5rem; }
  .stat-label { font-size: var(--fs-caption); }

  /* Cert grid: single column */
  .cert-grid, .cert-grid-3 { grid-template-columns: 1fr; }

  /* Client wall: 2 columns */
  .client-wall { grid-template-columns: repeat(2, 1fr); }

  /* Hero: even tighter */
  .hero-content h1 { font-size: 1.5rem; }
  .hero-content .section-label { font-size: var(--fs-caption); }

  /* Article card image smaller */
  .article-card-img { height: 160px; }

  /* Page hero */
  .page-hero h1 { font-size: 1.25rem; }

  /* CTA */
  .cta-banner { padding: var(--sp-lg) var(--sp-sm); }
  .cta-banner h2 { font-size: 1.125rem; }
  .mission-text { font-size: 1.0625rem; }
}