/*
==================================================
  Optimized CSS for HTX Trading Platform Website
  Version: 3.0 (Matches the HTX HTML rewrite)
  Description: Fast, accessible, mobile-first, Baidu SEO-friendly.
==================================================

TABLE OF CONTENTS
------------------
1.  :root - CSS Variables (Global Theme)
2.  Global Styles & Typography
3.  Header & Navigation
4.  Mobile Menu (Slicknav)
5.  Hero Section
6.  Service Section
7.  App CTA (Call to Action) Section
8.  Feature Section
9.  Screenshot / Video Section
10. FAQ Section
11. Footer
12. Utilities, Accessibility & Motion
==================================================
*/

/* 1) :root - CSS Variables (Global Theme)
-------------------------------------------------- */
:root {
  /* Palette — dark base + cyan accent (稳重+信任感) */
  --color-primary: #0d1321;          /* 深色主色（文本/标题） */
  --color-primary-dark: #0a0f1a;     /* Header/Footer 背景 */
  --color-surface: #0f1629;          /* 深色卡片/深背景 */
  --color-background: #ffffff;       /* 浅色背景 */
  --color-background-dark: #0b1220;  /* 深色区块背景 */
  --color-accent: #12c2e9;           /* 品牌强调色（CTA/链接） */
  --color-accent-2: #0ea5e9;         /* 次强调（hover/细节） */

  --color-text-strong: #111827;      /* 深色文本 */
  --color-text: #374151;             /* 正文文本 */
  --color-text-subtle: #6b7280;      /* 次要文本 */
  --color-text-on-dark: #e5e7eb;     /* 深色背景上的文本 */
  --color-text-on-dark-subtle: #a6b0c3;

  --shadow-soft: 0 8px 30px rgba(0,0,0,.12);
  --radius: 10px;

  /* Type */
  --font-primary: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei", sans-serif;

  /* Transitions */
  --t-fast: all .25s ease;
  --t-med: all .35s ease;
}

/* 2) Global Styles & Typography
-------------------------------------------------- */
html { scroll-behavior: smooth; }
* { box-sizing: border-box; }

body {
  font-family: var(--font-primary);
  color: var(--color-text);
  background: var(--color-background);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a { text-decoration: none; transition: var(--t-fast); }
a:hover { opacity: .9; }

.section-title {
  text-align: center;
  margin-bottom: 48px;
}
.section-title h2 {
  font-size: 32px;
  font-weight: 800;           /* 强化H2权重，有利于移动端首屏信息层级 */
  color: var(--color-text-strong);
  line-height: 1.25;
  /* 不对中文使用全大写 */
}
.section-title p {
  margin-top: 12px;
  font-size: 18px;
  color: var(--color-text-subtle);
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

.bg-gray {                       /* 用于深色区块 */
  background: linear-gradient(180deg, var(--color-background-dark), #0a0f1a);
}
.bg-gray .section-title h2 { color: var(--color-text-on-dark); }
.bg-gray .section-title p  { color: var(--color-text-on-dark-subtle); }

/* 使锚点跳转不被Header遮挡（利于移动端体验） */
#home, #feature, #app-feature, #price, #faq { scroll-margin-top: 84px; }

/* 3) Header & Navigation
-------------------------------------------------- */
.header-area {
  position: absolute;
  inset: 0 auto auto 0;
  width: 100%;
  z-index: 999;
  padding: 14px 0;
  background: transparent;
  transition: background-color .25s ease, box-shadow .25s ease;
}
.sticky-menu {
  position: fixed;
  background: rgba(10,15,26,.9);
  backdrop-filter: saturate(150%) blur(6px);
  box-shadow: 0 2px 12px rgba(0,0,0,.15);
}
.logo a img { max-width: 132px; height: auto; }

.main-menu nav ul {
  text-align: right;
  margin: 0; padding: 0; list-style: none;
}
.main-menu nav ul li { display: inline-block; }
.main-menu nav ul li a {
  color: #ffffff;
  font-size: 16px;
  font-weight: 600;
  margin-left: 28px;
  padding: 8px 0 8px 14px;
  position: relative;
}
.main-menu nav ul li a::before{
  content:'';
  position:absolute; left:-8px; top:50%; transform:translateY(-50%);
  height:2px; width:14px; opacity:0; background: var(--color-accent);
  transition: var(--t-fast);
}
.main-menu nav ul li.active a,
.main-menu nav ul li a:hover {
  color: var(--color-accent);
}
.main-menu nav ul li.active a::before,
.main-menu nav ul li a:hover::before { opacity:1; left:0; }

/* 4) Mobile Menu (Slicknav)
-------------------------------------------------- */
.slicknav_menu { padding: 0; background: transparent; margin-top: 0; }
.slicknav_btn { background: transparent; margin: 8px 8px 0; float: right; top: -45px; position: relative; }
.slicknav_menutxt { display: none; }
.slicknav_icon-bar { background: var(--color-accent); height: 2px; width: 24px; margin: 5px 0; }
.slicknav_nav {
  background: #1a2234;
  margin: 8px 0 0;
  padding: 5px 0;
  border-radius: 8px;
}
.slicknav_nav a {
  font-size: 15px; padding: 10px 16px; color: var(--color-text-on-dark);
}
.slicknav_nav a:hover {
  background: rgba(18,194,233,.15);
  color: #e9f6ff;
}

/* 5) Hero Section
-------------------------------------------------- */
.hero-area {
  min-height: 640px;
  position: relative;
  background: radial-gradient(1200px 600px at 20% 20%, #15223b, #0b1220 60%, #0a0f1a 100%);
}
.full-height { height: 100vh; }

.slider_overlay {
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(0,0,0,.25), rgba(0,0,0,.55));
}

.hero-content { position: relative; z-index: 1; }
.hero-content h1 {
  font-size: 44px;             /* 更贴合移动端 */
  color: #fff;
  margin: 0 0 14px;
  font-weight: 900;
  line-height: 1.2;
}
.hero-content .sub-heading {
  display: block;
  font-size: 22px;
  font-weight: 500;
  margin-top: 8px;
  color: #cfe7ff;
  letter-spacing: .3px;
}
.hero-content .hero-sub-title {
  color: #e6eef7;
  font-size: 17px;
  line-height: 28px;
  max-width: 840px;
  opacity: .95;
}

/* 唯一注册按钮（高对比+较大可点击区域） */
.hero-content .btn-register{
  display:inline-block;
  font-size:18px;
  font-weight:800;
  letter-spacing:.2px;
  color:#001018;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-2));
  padding: 14px 36px;
  border-radius: 999px;
  margin-top: 28px;
  border: 0;
  box-shadow: 0 10px 28px rgba(14,165,233,.35);
  transition: transform .18s ease, box-shadow .18s ease;
}
.hero-content .btn-register:hover{
  transform: translateY(-3px);
  box-shadow: 0 14px 34px rgba(14,165,233,.48);
  color:#001018;
}

a.scrl_me_down {
  position:absolute; left:50%; bottom:4%; transform:translateX(-50%); z-index:9;
}
a.scrl_me_down span {
  display:inline-block; color:#cfe7ff; font-size:40px; animation: scrolldown 1.5s ease-in-out infinite;
}
@keyframes scrolldown { 0%,100%{transform:translateY(-4px);opacity:1;} 50%{transform:translateY(10px);opacity:.55;} }

/* 右侧媒体容器在深色背景下留白 */
.screen-slides-area { position: relative; z-index: 1; }
#myVideo { border-radius: 16px; box-shadow: var(--shadow-soft); }

/* 6) Service Section
-------------------------------------------------- */
.service-area { background:#fff; }
.single-service{
  text-align:center; padding:28px 22px; border-radius: var(--radius);
  transition: var(--t-med);
  background: #fff;
  border: 1px solid #eef2f7;
}
.single-service:hover{
  transform: translateY(-6px);
  box-shadow: 0 12px 36px rgba(16,24,40,.08);
}
.single-service h3{
  font-size:20px; color: var(--color-text-strong); margin-bottom: 10px; font-weight: 700;
}
.single-service p{ font-size:16px; line-height:1.7; color: var(--color-text); }

/* 7) App CTA Section (深色区块，只有介绍，无额外按钮) */
.app-cta-area { background: var(--color-surface); }
.app-cta-area .appcta-content h2{
  font-size:30px; line-height:1.25; margin-bottom:16px; color: var(--color-text-on-dark);
}
.app-cta-area .appcta-content p{
  font-size:16px; color: var(--color-text-on-dark-subtle);
}
.mscreen-right img, .mscreen-left img { border-radius: 14px; box-shadow: var(--shadow-soft); }

/* 8) Feature Section */
.app-feature-area { background:#fff; }
.feature-item{
  margin-top: 40px; display:flex; align-items:flex-start; text-align:left;
}
.feature-item .icon{
  flex-shrink:0; margin-right: 16px; height:54px; width:54px;
  border:1px dashed #e5e7eb; border-radius:50%;
  display:flex; align-items:center; justify-content:center; font-size:24px; color:#0f172a;
}
.right-side .feature-item .icon{ order:1; margin-right:0; margin-left:16px; }
.right-side .feature-item .content{ order:0; }
.feature-item h3{
  font-size:18px; color: var(--color-text-strong); margin:0 0 6px; font-weight:700;
}
.feature-item p{ color: var(--color-text); }

/* 9) Screenshot / Video Section */
.screenshot-area { background: var(--color-surface); }
.screenshot-area .section-title h2 { color: var(--color-text-on-dark); }
.screenshot-area .section-title p  { color: var(--color-text-on-dark-subtle); }
.screenshot-pagination{ margin-top: 48px; text-align:center; }
.swiper-pagination-bullet{
  width: 10px; height:10px; background:#c5d2e8; opacity:1; margin:0 4px; border-radius:50%; transition: var(--t-fast);
}
.swiper-pagination-bullet-active{ background: var(--color-accent); transform: scale(1.2); }

/* 10) FAQ Section */
.accordion-area .card{
  margin-bottom: 12px; border:1px solid #e5e7eb; border-radius: 10px; overflow:hidden; box-shadow:none; background:#fff;
}
.accordion-area .card-header{
  padding:0; border-bottom:1px solid #eef2f7; background:#fff;
}
.accordion-area .card-header h3{ margin:0; }
.accordion-area .card-header h3 button{
  border:0; background:transparent; padding:18px 54px 18px 18px; width:100%; text-align:left;
  font-size:16px; color: var(--color-text-strong); font-weight:700; position:relative; outline:none; cursor:pointer;
}
.accordion-area .card-header h3 button::before{ /* 一横 */
  content:''; position:absolute; right:22px; top:50%; transform:translateY(-50%); height:2px; width:12px; background:#94a3b8;
}
.accordion-area .card-header h3 button::after{  /* 一竖 -> 展开后转成减号 */
  content:''; position:absolute; right:27px; top:calc(50% - 6px); width:2px; height:12px; background:#94a3b8; transition: transform .25s ease;
}
.accordion-area .card-header h3 button[aria-expanded="true"]::after{ transform: rotate(90deg); }
.accordion-area .card-body{
  font-size:15px; line-height:1.8; padding:18px; color: var(--color-text);
}
.faq-left-thumb img{ max-width:100%; border-radius: 12px; box-shadow: var(--shadow-soft); }

/* 11) Footer */
.footer-area{ background: var(--color-primary-dark); }
.footer-content{ text-align:center; }
.footer-content p{
  color: #97a3b6; font-size:14px; margin: 4px 0;
}

/* 12) Utilities, Accessibility & Motion
-------------------------------------------------- */
.ptb--50{ padding:50px 0; }
.ptb--100{ padding:100px 0; }
.pb--100{ padding-bottom:100px; }
.pt--70{ padding-top:70px; }

/* 在深色区块内自动反色的标题/文本（兜底） */
.bg-gray h1, .bg-gray h2, .bg-gray h3, .bg-gray p, .bg-gray a { color: var(--color-text-on-dark); }
.bg-gray a:hover { color: #b8ecff; }

/* 键盘可见性 */
a:focus-visible, button:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
  border-radius: 6px;
}

/* 降低动画以避免眩晕（系统偏好） */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}

/* 响应式优化 */
@media (max-width: 991.98px){
  .hero-content h1{ font-size: 34px; }
  .hero-content .sub-heading{ font-size: 18px; }
  .main-menu nav ul li a{ margin-left: 18px; }
}
@media (max-width: 767.98px){
  .header-area{ padding: 10px 0; }
  .hero-area{ min-height: 560px; }
  .hero-content .hero-sub-title{ font-size: 16px; }
  .single-service{ padding:24px 18px; }
  .section-title h2{ font-size: 28px; }
}