/* ================================================
   灵千科技官网 — 样式表
   风格A：Nu1L深蓝科技风
   背景：#041031 / 主强调：#00d4aa松绿
   ================================================ */

/* ---- CSS变量 ---- */
:root {
  --bg-deep: #041031;
  --bg-card: #0a1a40;
  --bg-card-hover: #0d2060;
  --bg-section-alt: #061438;
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-green: rgba(0, 212, 170, 0.3);
  --green: #00d4aa;
  --green-dim: rgba(0, 212, 170, 0.15);
  --blue: #1a73e8;
  --text-white: #ffffff;
  --text-gray: #8a9bbf;
  --text-dim: #5a6b8a;
  --font-cn: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", "Courier New", monospace;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 40px rgba(0, 212, 170, 0.15);
  --nav-height: 70px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ---- 重置与基础 ---- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-cn);
  background-color: var(--bg-deep);
  color: var(--text-white);
  line-height: 1.7;
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

ul { list-style: none; }

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

/* ---- 滚动条 ---- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-deep); }
::-webkit-scrollbar-thumb { background: var(--green); border-radius: 3px; }

/* ---- 文字选中 ---- */
::selection { background: var(--green); color: var(--bg-deep); }

/* ---- 通用动画 ---- */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

/* ================================================
   导航栏
   ================================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  background: rgba(4, 16, 49, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  transition: var(--transition);
}

.navbar.scrolled {
  background: rgba(4, 16, 49, 0.95);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-white);
  transition: var(--transition);
}

.nav-logo:hover { color: var(--green); }

.logo-img {
  height: 65px;
  width: auto;
  display: block;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 40px;
}

.nav-links a {
  font-size: 0.95rem;
  color: var(--text-gray);
  font-weight: 500;
  transition: var(--transition);
  position: relative;
  padding: 4px 0;
}

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

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

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

/* 移动端菜单按钮 */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-white);
  border-radius: 2px;
  transition: var(--transition);
}

/* ================================================
   首屏 Hero
   ================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: calc(var(--nav-height) + 40px) 24px 60px;
  overflow: hidden;
  background: var(--bg-deep);
}

/* 背景渐变效果 */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% 0%, rgba(0, 212, 170, 0.08) 0%, transparent 70%),
    radial-gradient(ellipse 60% 40% at 80% 80%, rgba(26, 115, 232, 0.06) 0%, transparent 60%);
  pointer-events: none;
}

/* 彩色装饰线 */
.hero-bg-effects {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.gradient-line {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(
    90deg,
    transparent 0%,
    #1a73e8 10%,
    #a855f7 30%,
    #ef4444 50%,
    #f97316 70%,
    #eab308 90%,
    transparent 100%
  );
  background-size: 200% 100%;
  animation: gradientShift 6s ease infinite;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  width: 100%;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.hero-title {
  font-size: clamp(2.4rem, 6vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.15;
  background: linear-gradient(135deg, #ffffff 0%, #e0f7f4 50%, var(--green) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: fadeInUp 0.8s ease-out;
}

.hero-subtitle {
  font-size: 1.2rem;
  color: #c8daf0;
  font-weight: 400;
  animation: fadeInUp 0.8s ease-out 0.15s both;
}

.hero-positioning {
  font-size: 0.95rem;
  color: #00e8bb;
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  animation: fadeInUp 0.8s ease-out 0.25s both;
  text-shadow: 0 0 12px rgba(0, 232, 187, 0.4);
}

/* ================================================
   AI对话框
   ================================================ */
.chat-container {
  width: 100%;
  max-width: min(1296px, 94vw);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card), var(--shadow-glow);
  animation: fadeInUp 0.8s ease-out 0.35s both;
  /* 锁死高度，不随内容变化 */
  height: 580px;
  display: flex;
  flex-direction: column;
}

.chat-messages {
  padding: 20px 24px;
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.chat-message {
  display: flex;
  gap: 10px;
  animation: fadeIn 0.3s ease-out;
  max-width: 80%;
}

.ai-message {
  align-self: flex-start;
}

.user-message {
  align-self: flex-end;
  flex-direction: row-reverse;
}

.message-avatar {
  font-size: 1.2rem;
  line-height: 1.4;
  flex-shrink: 0;
  width: 30px;
  height: 30px;
  background: var(--green-dim);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  align-self: flex-end;
}

.user-message .message-avatar {
  background: rgba(26, 115, 232, 0.15);
}

.message-content {
  min-width: 0;
}

.message-content p {
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--text-white);
  margin-bottom: 0;
}

/* AI教练气泡 — 微信风格，靠左 */
.ai-message .message-content p {
  background: rgba(0, 212, 170, 0.1);
  border: 1px solid rgba(0, 212, 170, 0.18);
  border-radius: 16px 16px 16px 4px;
  padding: 10px 14px;
}

/* 学生气泡 — 微信风格，靠右 */
.user-message .message-content p {
  background: rgba(26, 115, 232, 0.15);
  border: 1px solid rgba(26, 115, 232, 0.2);
  border-radius: 16px 16px 4px 16px;
  padding: 10px 14px;
}

/* 推荐话题按钮 */
.quick-topics {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 8px;
}

.topic-btn {
  background: var(--green-dim);
  border: 1px solid var(--border-green);
  color: var(--green);
  font-size: 0.82rem;
  padding: 6px 14px;
  border-radius: 20px;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-cn);
  font-weight: 500;
}

.topic-btn:hover {
  background: var(--green);
  color: var(--bg-deep);
  transform: translateY(-1px);
}



/* AI思考中 */
.ai-thinking {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-dim);
  font-size: 0.85rem;
  padding: 8px 0;
}

.ai-thinking-dots span {
  display: inline-block;
  width: 6px;
  height: 6px;
  background: var(--green);
  border-radius: 50%;
  animation: pulse 1.4s ease-in-out infinite;
}

.ai-thinking-dots span:nth-child(2) { animation-delay: 0.2s; }
.ai-thinking-dots span:nth-child(3) { animation-delay: 0.4s; }

/* 打字机光标 */
.typing-cursor::after {
  content: '|';
  animation: blink 1s step-end infinite;
  color: var(--green);
  font-weight: 700;
}

/* 输入区 */
.chat-input-area {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 24px;
  border-top: 1px solid var(--border-subtle);
  background: rgba(4, 16, 49, 0.5);
  flex-shrink: 0;
}

.chat-input {
  flex: 1;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-white);
  font-size: 0.95rem;
  padding: 12px 16px;
  font-family: var(--font-cn);
  transition: var(--transition);
  outline: none;
}

.chat-input::placeholder { color: var(--text-dim); }

.chat-input:focus {
  border-color: var(--green);
  background: rgba(0, 212, 170, 0.05);
  box-shadow: 0 0 0 3px rgba(0, 212, 170, 0.1);
}

.chat-send {
  width: 44px;
  height: 44px;
  background: var(--green);
  border: none;
  border-radius: var(--radius-sm);
  color: var(--bg-deep);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  flex-shrink: 0;
}

.chat-send:hover {
  background: #00e8bb;
  transform: scale(1.05);
}

.chat-send:active { transform: scale(0.97); }

.chat-send:disabled {
  background: var(--text-dim);
  cursor: not-allowed;
  transform: none;
}

/* 滚动提示 */
.scroll-hint {
  margin-top: 32px;
  font-size: 0.85rem;
  color: #90b8d8;
  animation: fadeInUp 0.8s ease-out 0.6s both;
}

.scroll-hint span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border: 1px solid var(--border-subtle);
  border-radius: 20px;
}

/* ================================================
   通用区块
   ================================================ */
.section {
  padding: 100px 0;
}

.section-container {
  max-width: min(1280px, 90vw);
  margin: 0 auto;
  padding: 0 24px;
}

.section-title {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
  color: #ffffff;
}

.section-subtitle {
  text-align: center;
  font-size: 1.1rem;
  color: #c0d8f0;
  margin-bottom: 12px;
}

.section-desc {
  text-align: center;
  font-size: 0.95rem;
  color: #b0cce8;
  max-width: min(860px, 85vw);
  margin: 0 auto 60px;
  line-height: 1.8;
}

/* ================================================
   产品特点卡片
   ================================================ */
/* 区块分割线通用样式 */
.section-divider {
  position: relative;
}
.section-divider::before {
  content: '';
  position: absolute;
  top: 0;
  left: 8%;
  right: 8%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(0, 212, 170, 0.3), transparent);
  z-index: 1;
}

.product-section {
  background: #071640;
  position: relative;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  justify-items: center;
}

/* 下面两个居中：用6列网格实现 */
@media (min-width: 768px) {
  .features-grid {
    grid-template-columns: repeat(6, 1fr);
  }
  .features-grid .feature-card:nth-child(1) { grid-column: 1 / 3; }
  .features-grid .feature-card:nth-child(2) { grid-column: 3 / 5; }
  .features-grid .feature-card:nth-child(3) { grid-column: 5 / 7; }
  .features-grid .feature-card:nth-child(4) { grid-column: 2 / 4; }
  .features-grid .feature-card:nth-child(5) { grid-column: 4 / 6; }
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 36px 32px;
  text-align: center;
  transition: var(--transition);
  cursor: default;
  display: flex;
  flex-direction: column;
  gap: 12px;
  position: relative;
  overflow: hidden;
  width: 100%;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--green), var(--blue));
  opacity: 0;
  transition: var(--transition);
}

.feature-card:hover {
  border-color: var(--border-green);
  transform: translateY(-4px);
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

.feature-card:hover::before { opacity: 1; }

.feature-icon {
  width: 72px;
  height: 72px;
  margin: 0 auto 8px;
  background: var(--green-dim);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--green);
  flex-shrink: 0;
}

.feature-icon svg {
  width: 36px;
  height: 36px;
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 6px;
  line-height: 1.4;
}

.feature-brief {
  font-size: 0.88rem;
  color: var(--green);
  font-weight: 500;
  line-height: 1.5;
}

.feature-detail {
  font-size: 0.85rem;
  color: #b0cce8;
  line-height: 1.75;
  flex: 1;
}

.feature-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: auto;
  justify-content: center;
}

.feature-stats span {
  font-size: 0.72rem;
  color: var(--text-dim);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-subtle);
  padding: 4px 10px;
  border-radius: 4px;
  font-family: var(--font-mono);
}

/* ================================================
   解决方案
   ================================================ */
.solutions-section {
  background: var(--bg-deep);
  position: relative;
}

.solutions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.solution-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 36px 32px;
  text-align: center;
  transition: var(--transition);
}

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

.solution-icon {
  width: 72px;
  height: 72px;
  margin: 0 auto 20px;
  background: var(--green-dim);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--green);
}

.solution-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 14px;
  line-height: 1.4;
}

.solution-card p {
  font-size: 0.88rem;
  color: #b0cce8;
  line-height: 1.8;
  text-align: left;
}

/* ================================================
   关于我们
   ================================================ */
.about-section {
  background: #071640;
  position: relative;
}

.brand-area {
  text-align: center;
  margin-bottom: 80px;
}

.brand-slogan {
  font-size: 1rem;
  color: #00e8bb;
  font-family: var(--font-mono);
  letter-spacing: 0.05em;
  margin-bottom: 48px;
  text-shadow: 0 0 10px rgba(0, 232, 187, 0.3);
}

.brand-explain {
  display: flex;
  justify-content: center;
  gap: 100px;
}

.brand-word {
  flex: 1;
  max-width: 260px;
  text-align: center;
}

.brand-char {
  display: block;
  font-size: 3rem;
  font-weight: 800;
  background: linear-gradient(135deg, #fff, var(--green));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 12px;
}

.brand-word p {
  font-size: 0.88rem;
  color: #b0cce8;
  line-height: 1.8;
}

/* Nu1L战队 */
.team-area {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 48px;
  text-align: center;
}

.team-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 20px;
}

.team-area > p {
  font-size: 0.92rem;
  color: #b0cce8;
  line-height: 1.9;
  max-width: 860px;
  margin: 0 auto 36px;
  text-align: left;
}

.achievement-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px;
}

.achievement-item {
  display: flex;
  align-items: center;
  gap: 12px;
  background: rgba(0, 212, 170, 0.06);
  border: 1px solid var(--border-green);
  border-radius: 8px;
  padding: 10px 20px;
  transition: var(--transition);
}

.achievement-item:hover {
  background: var(--green-dim);
  transform: translateY(-2px);
}

.achievement-year {
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--green);
  font-family: var(--font-mono);
}

.achievement-text {
  font-size: 0.88rem;
  color: #e0f0ff;
  font-weight: 500;
}

/* ================================================
   联系方式（白底反差）
   ================================================ */
.contact-section.section-divider::before {
  background: linear-gradient(90deg, transparent, rgba(26, 115, 232, 0.3), transparent);
}

.contact-section {
  background: #ffffff;
  color: #1a1a2e;
  position: relative;
}

.contact-section .section-title {
  background: linear-gradient(135deg, #1a1a2e, #1a73e8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.contact-desc {
  text-align: center;
  font-size: 0.95rem;
  color: #5a6b8a;
  margin-bottom: 40px;
}

.contact-grid {
  display: flex;
  justify-content: center;
  gap: 48px;
  flex-wrap: wrap;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 14px;
  color: #1a1a2e;
}

.contact-item svg {
  color: var(--blue);
  flex-shrink: 0;
}

.contact-label {
  display: block;
  font-size: 0.78rem;
  color: #8a9bbf;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 2px;
}

.contact-value {
  font-size: 1rem;
  font-weight: 600;
  color: #1a1a2e;
}

a.contact-value:hover {
  color: var(--blue);
  text-decoration: underline;
}

/* ================================================
   页脚
   ================================================ */
.footer {
  background: #020a1a;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding: 28px 24px;
  text-align: center;
}

.footer p {
  font-size: 0.85rem;
  color: var(--text-dim);
}

/* ================================================
   API Key弹窗
   ================================================ */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(2, 10, 26, 0.85);
  backdrop-filter: blur(8px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 36px;
  max-width: 480px;
  width: 100%;
  box-shadow: var(--shadow-card);
  transform: translateY(20px);
  transition: var(--transition);
}

.modal-overlay.active .modal-content {
  transform: translateY(0);
}

.modal-content h3 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-white);
  margin-bottom: 12px;
}

.modal-content > p {
  font-size: 0.88rem;
  color: var(--text-gray);
  line-height: 1.7;
  margin-bottom: 24px;
}

.modal-field {
  margin-bottom: 18px;
}

.modal-field label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-gray);
  margin-bottom: 6px;
  font-weight: 500;
}

.modal-field input,
.modal-field select {
  width: 100%;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-white);
  font-size: 0.95rem;
  padding: 11px 14px;
  font-family: var(--font-cn);
  transition: var(--transition);
  outline: none;
}

.modal-field select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%238a9bbf' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 36px;
  cursor: pointer;
}

.modal-field select option {
  background: var(--bg-card);
  color: var(--text-white);
}

.modal-field input:focus,
.modal-field select:focus {
  border-color: var(--green);
  box-shadow: 0 0 0 3px rgba(0, 212, 170, 0.1);
}

.modal-actions {
  display: flex;
  gap: 12px;
  margin-top: 24px;
}

.btn-secondary,
.btn-primary {
  flex: 1;
  padding: 12px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  font-family: var(--font-cn);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-subtle);
  color: var(--text-gray);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-white);
}

.btn-primary {
  background: var(--green);
  color: var(--bg-deep);
}

.btn-primary:hover {
  background: #00e8bb;
  transform: translateY(-1px);
}

.modal-hint {
  font-size: 0.78rem;
  color: var(--text-dim);
  margin-top: 16px;
  text-align: center;
  line-height: 1.5;
}

/* ================================================
   滚动动画
   ================================================ */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ================================================
   响应式
   ================================================ */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .features-grid .feature-card:nth-child(1),
  .features-grid .feature-card:nth-child(2),
  .features-grid .feature-card:nth-child(3),
  .features-grid .feature-card:nth-child(4),
  .features-grid .feature-card:nth-child(5) { grid-column: auto; }
  .solutions-grid { grid-template-columns: repeat(2, 1fr); }
  .brand-explain { gap: 32px; }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: rgba(4, 16, 49, 0.98);
    flex-direction: column;
    padding: 20px;
    gap: 20px;
    border-bottom: 1px solid var(--border-subtle);
  }

  .nav-links.open { display: flex; }

  .nav-toggle { display: flex; }

  .hero { padding-top: calc(var(--nav-height) + 24px); }

  .hero-title { font-size: 2rem; }
  .hero-subtitle { font-size: 1rem; }

  .features-grid {
    grid-template-columns: 1fr;
  }
  .features-grid .feature-card:nth-child(1),
  .features-grid .feature-card:nth-child(2),
  .features-grid .feature-card:nth-child(3),
  .features-grid .feature-card:nth-child(4),
  .features-grid .feature-card:nth-child(5) { grid-column: auto; }
  .solutions-grid { grid-template-columns: 1fr; }

  .brand-explain {
    flex-direction: column;
    align-items: center;
    gap: 32px;
  }

  .brand-word { max-width: 320px; }

  .team-area { padding: 32px 24px; }

  .contact-grid {
    flex-direction: column;
    align-items: center;
    gap: 24px;
  }

  .achievement-list { flex-direction: column; align-items: center; }

  .modal-content { padding: 24px; }
}

@media (max-width: 480px) {
  .section { padding: 72px 16px; }
  .feature-card { padding: 24px 20px; }
  .solution-card { padding: 28px 20px; }
  .chat-messages { padding: 16px; }
  .chat-input-area { padding: 12px 16px; }
}