/* ===== RESET ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;border:0;font:inherit;vertical-align:baseline}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%;text-size-adjust:100%}
body{min-height:100vh;line-height:1.6;background-color:#0D1117;color:#E0EFFC;font-family:'Inter',sans-serif;font-weight:400;font-size:1rem;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
img,svg,video{display:block;max-width:100%;height:auto}
a{color:inherit;text-decoration:none}
ul,ol{list-style:none}
button{cursor:pointer;background:none;border:none;color:inherit;font:inherit}
h1,h2,h3,h4,h5,h6{font-family:'Exo 2',sans-serif;font-weight:800;color:#E0EFFC;line-height:1.2}
:focus-visible{outline:2px solid #FF6B35;outline-offset:3px;border-radius:2px}
::selection{background:#FF6B35;color:#0D1117}

/* ===== VARIABLES ===== */
:root{
  --clr-primary:#0A1F3F;
  --clr-secondary:#005B96;
  --clr-accent1:#FF6B35;
  --clr-accent2:#39FF14;
  --clr-bg-dark:#0D1117;
  --clr-bg-light:#1A2A3A;
  --clr-surface:#142433;
  --clr-text-primary:#E0EFFC;
  --clr-text-secondary:#8899AA;
  --clr-border:#2C3E50;
  --font-headline:'Exo 2',sans-serif;
  --font-body:'Inter',sans-serif;
  --font-data:'JetBrains Mono',monospace;
  --font-caption:'Inter',sans-serif;
  --header-height:64px;
  --content-max:1200px;
  --content-narrow:800px;
  --content-wide:1400px;
  --gap-sm:0.5rem;
  --gap-md:1rem;
  --gap-lg:2rem;
  --gap-xl:4rem;
  --radius-sm:4px;
  --radius-md:8px;
  --transition-fast:0.2s ease;
  --transition-base:0.3s ease;
  --shadow-nav:0 4px 20px rgba(0,0,0,0.5);
}

/* ===== SKIP LINK ===== */
.skip-link{
  position:fixed;top:-100%;left:var(--gap-md);z-index:10000;
  padding:0.75rem 1.5rem;background:#FF6B35;color:#0D1117;
  font-family:var(--font-body);font-weight:600;font-size:0.9rem;
  border-radius:0 0 var(--radius-md) var(--radius-md);
  transition:top var(--transition-fast);
}
.skip-link:focus{top:0;outline:none;}

/* ===== HEADER ===== */
.header{
  position:fixed;top:0;left:0;right:0;z-index:9000;
  height:var(--header-height);
  background:transparent;
  transition:background var(--transition-base),box-shadow var(--transition-base);
  will-change:background;
}
.header[data-scrolled]{
  background:rgba(10,31,63,0.96);
  box-shadow:var(--shadow-nav);
  backdrop-filter:blur(12px);
  -webkit-backdrop-filter:blur(12px);
}
.header__inner{
  max-width:var(--content-wide);margin:0 auto;
  display:flex;align-items:center;justify-content:space-between;
  height:100%;padding:0 var(--gap-lg);
}
.header__brand{flex-shrink:0;}
.header__logo{
  display:flex;flex-direction:column;gap:0;
  line-height:1.1;
}
.header__logo-text{
  font-family:var(--font-headline);font-weight:800;font-size:1.4rem;
  color:var(--clr-text-primary);letter-spacing:0.02em;
}
.header__logo-subtext{
  font-family:var(--font-caption);font-weight:300;font-size:0.65rem;
  color:var(--clr-accent1);letter-spacing:0.3em;text-transform:uppercase;
}
.header__nav{margin:0 var(--gap-lg);}
.header__nav-list{
  display:flex;gap:var(--gap-md);
}
.header__nav-list a{
  font-family:var(--font-body);font-weight:500;font-size:0.9rem;
  color:var(--clr-text-secondary);padding:0.4rem 0.8rem;
  border-radius:var(--radius-sm);transition:color var(--transition-fast),background var(--transition-fast);
  position:relative;white-space:nowrap;
}
.header__nav-list a:hover,
.header__nav-list a:focus-visible{color:var(--clr-text-primary);background:rgba(255,255,255,0.06);}
.header__nav-list a[aria-current="page"]{
  color:var(--clr-accent1);font-weight:700;
}
.header__nav-list a[aria-current="page"]::after{
  content:'';position:absolute;bottom:0;left:0.8rem;right:0.8rem;
  height:2px;background:var(--clr-accent1);
  border-radius:1px;
}
.header__cta{
  flex-shrink:0;
  font-family:var(--font-headline);font-weight:700;font-size:0.85rem;
  color:#0D1117;background:var(--clr-accent1);
  padding:0.5rem 1.4rem;border-radius:4px;
  transition:background var(--transition-fast),transform var(--transition-fast);
  text-transform:uppercase;letter-spacing:0.05em;
  clip-path:polygon(8px 0,100% 0,calc(100% - 8px) 100%,0 100%);
}
.header__cta:hover,.header__cta:focus-visible{background:#e85d2c;transform:translateY(-1px);}
.header__toggle{display:none;flex-direction:column;gap:5px;padding:6px;border-radius:var(--radius-sm);}
.header__toggle-line{
  display:block;width:24px;height:2px;background:var(--clr-text-primary);
  border-radius:2px;transition:transform var(--transition-fast),opacity var(--transition-fast);
  transform-origin:center;
}
.header__toggle[aria-expanded="true"] .header__toggle-line:nth-child(1){transform:translateY(7px) rotate(45deg);}
.header__toggle[aria-expanded="true"] .header__toggle-line:nth-child(2){opacity:0;}
.header__toggle[aria-expanded="true"] .header__toggle-line:nth-child(3){transform:translateY(-7px) rotate(-45deg);}

/* ===== FOOTER ===== */
.footer{
  background:var(--clr-primary);color:var(--clr-text-secondary);
  border-top:1px solid var(--clr-border);margin-top:var(--gap-xl);
}
.footer__inner{
  max-width:var(--content-wide);margin:0 auto;
  padding:var(--gap-xl) var(--gap-lg) var(--gap-lg);
  display:grid;grid-template-columns:2fr 1.5fr 1fr;gap:var(--gap-lg);
}
.footer__brand{}
.footer__logo{
  font-family:var(--font-headline);font-weight:800;font-size:1.6rem;
  color:var(--clr-text-primary);letter-spacing:0.02em;
}
.footer__subtext{
  font-family:var(--font-caption);font-weight:300;font-size:0.7rem;
  color:var(--clr-accent1);letter-spacing:0.3em;text-transform:uppercase;
  margin-top:2px;
}
.footer__trust{
  margin-top:var(--gap-md);font-size:0.85rem;line-height:1.7;max-width:400px;
  color:var(--clr-text-secondary);
}
.footer__columns{display:grid;grid-template-columns:repeat(3,1fr);gap:var(--gap-lg);grid-column:2/4;}
.footer__column-title{
  font-family:var(--font-headline);font-weight:700;font-size:0.8rem;
  color:var(--clr-accent1);text-transform:uppercase;letter-spacing:0.08em;
  margin-bottom:var(--gap-sm);
}
.footer__column-list{display:flex;flex-direction:column;gap:0.4rem;}
.footer__column-list li{
  font-size:0.85rem;color:var(--clr-text-secondary);line-height:1.5;
}
.footer__column-list a{
  color:var(--clr-text-secondary);transition:color var(--transition-fast);
  position:relative;
}
.footer__column-list a::after{
  content:'';position:absolute;bottom:-2px;left:0;right:0;
  height:1px;background:var(--clr-accent1);transform:scaleX(0);
  transform-origin:left;transition:transform var(--transition-fast);
}
.footer__column-list a:hover,.footer__column-list a:focus-visible{color:var(--clr-text-primary);}
.footer__column-list a:hover::after,.footer__column-list a:focus-visible::after{transform:scaleX(1);}
.footer__info{
  grid-column:1/-1;display:flex;justify-content:space-between;align-items:center;
  padding-top:var(--gap-lg);margin-top:var(--gap-lg);
  border-top:1px solid var(--clr-border);font-size:0.8rem;color:var(--clr-text-secondary);
}
.footer__copyright,.footer__icp{margin:0;}

/* ===== PROGRESS BAR ===== */
[data-progress-bar]{
  position:fixed;top:var(--header-height);left:0;right:0;z-index:8999;
  height:3px;background:transparent;pointer-events:none;
}
[data-progress-bar]::after{
  content:'';display:block;height:100%;width:0%;
  background:linear-gradient(90deg,var(--clr-accent2),var(--clr-accent1));
  transition:width 0.15s ease;
  border-radius:0 2px 2px 0;
}

/* ===== BACK TO TOP ===== */
[data-back-to-top]{
  position:fixed;bottom:2rem;right:2rem;z-index:8000;
  width:48px;height:48px;border-radius:50%;
  background:var(--clr-surface);border:1px solid var(--clr-border);
  color:var(--clr-accent1);font-size:1.2rem;display:flex;align-items:center;justify-content:center;
  opacity:0;visibility:hidden;transform:translateY(16px);
  transition:opacity var(--transition-base),visibility var(--transition-base),transform var(--transition-base),background var(--transition-fast);
  box-shadow:0 4px 16px rgba(0,0,0,0.4);
}
[data-back-to-top].visible{
  opacity:1;visibility:visible;transform:translateY(0);
}
[data-back-to-top]:hover,[data-back-to-top]:focus-visible{
  background:var(--clr-accent1);color:#0D1117;border-color:var(--clr-accent1);
}
[data-back-to-top]::after{content:'↑';font-weight:700;font-size:1.2rem;line-height:1;}

/* ===== GENERAL COMPONENTS ===== */
.container{max-width:var(--content-max);margin:0 auto;padding:0 var(--gap-lg);}
.container-narrow{max-width:var(--content-narrow);margin:0 auto;padding:0 var(--gap-lg);}
.container-wide{max-width:var(--content-wide);margin:0 auto;padding:0 var(--gap-lg);}
.section{padding:var(--gap-xl) 0;}
.section-sm{padding:var(--gap-lg) 0;}

.grid{display:grid;gap:var(--gap-lg);}
.grid-2{grid-template-columns:repeat(2,1fr);}
.grid-3{grid-template-columns:repeat(3,1fr);}
.grid-4{grid-template-columns:repeat(4,1fr);}

/* ===== PANEL CORNER (斜切面板) ===== */
.panel-corner{
  background:var(--clr-surface);padding:var(--gap-lg);
  clip-path:polygon(16px 0,100% 0,calc(100% - 16px) 100%,0 100%);
  border-left:3px solid var(--clr-accent1);
  transition:transform var(--transition-fast),box-shadow var(--transition-fast);
}
.panel-corner:hover{transform:translateY(-2px);box-shadow:0 8px 32px rgba(0,0,0,0.3);}

/* ===== DATA HIGHLIGHT ===== */
.data-highlight{
  font-family:var(--font-data);font-weight:500;font-size:1.2rem;
  color:var(--clr-accent2);letter-spacing:0.02em;
}
.data-highlight-lg{font-size:2rem;font-weight:700;}

/* ===== DIVIDER SLASH (斜线装饰) ===== */
.divider-slash{
  height:4px;background:linear-gradient(135deg,var(--clr-accent1) 30%,var(--clr-accent2) 70%);
  clip-path:polygon(0 0,100% 0,calc(100% - 20px) 100%,20px 100%);
  margin:var(--gap-lg) 0;width:120px;
}

/* ===== ROTATED NOTE (旋转注释) ===== */
.note-rotated{
  font-family:var(--font-caption);font-weight:300;font-size:0.75rem;
  color:var(--clr-text-secondary);writing-mode:vertical-rl;
  transform:rotate(180deg);letter-spacing:0.15em;
  opacity:0.7;white-space:nowrap;
}

/* ===== BREADCRUMB ===== */
.breadcrumb{display:flex;flex-wrap:wrap;gap:0.4rem 0.8rem;font-size:0.85rem;color:var(--clr-text-secondary);margin-bottom:var(--gap-lg);}
.breadcrumb a{color:var(--clr-text-secondary);transition:color var(--transition-fast);}
.breadcrumb a:hover{color:var(--clr-accent1);}
.breadcrumb>[aria-current="page"]{color:var(--clr-text-primary);font-weight:600;}
.breadcrumb li+li::before{content:'/';margin-right:0.8rem;color:var(--clr-border);}

/* ===== BUTTON ===== */
.btn{
  display:inline-flex;align-items:center;gap:0.5rem;
  font-family:var(--font-headline);font-weight:700;font-size:0.85rem;
  padding:0.6rem 1.6rem;border-radius:4px;
  transition:background var(--transition-fast),transform var(--transition-fast),color var(--transition-fast);
  text-transform:uppercase;letter-spacing:0.04em;white-space:nowrap;
}
.btn-primary{background:var(--clr-accent1);color:#0D1117;}
.btn-primary:hover,.btn-primary:focus-visible{background:#e85d2c;transform:translateY(-1px);}
.btn-secondary{background:transparent;color:var(--clr-text-primary);border:1px solid var(--clr-border);}
.btn-secondary:hover,.btn-secondary:focus-visible{background:var(--clr-surface);border-color:var(--clr-accent1);}
.btn-outline{background:transparent;color:var(--clr-accent1);border:1px solid var(--clr-accent1);}
.btn-outline:hover,.btn-outline:focus-visible{background:var(--clr-accent1);color:#0D1117;}

/* ===== CARD ===== */
.card{background:var(--clr-surface);padding:var(--gap-lg);border-radius:0;border-left:3px solid var(--clr-secondary);transition:transform var(--transition-fast),box-shadow var(--transition-fast);}
.card:hover{transform:translateY(-2px);box-shadow:0 8px 32px rgba(0,0,0,0.3);}
.card__title{font-family:var(--font-headline);font-weight:700;font-size:1.1rem;margin-bottom:var(--gap-sm);}
.card__text{font-size:0.9rem;color:var(--clr-text-secondary);line-height:1.7;}

/* ===== RESPONSIVE ===== */
@media(max-width:900px){
  .header__nav{position:fixed;top:var(--header-height);left:0;right:0;bottom:0;
    background:rgba(10,31,63,0.98);backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);
    padding:var(--gap-lg);transform:translateX(100%);transition:transform var(--transition-base);
    overflow-y:auto;margin:0;z-index:9001;}
  .header__nav[data-open]{transform:translateX(0);}
  .header__nav-list{flex-direction:column;gap:0.2rem;}
  .header__nav-list a{font-size:1.1rem;padding:0.8rem 1rem;display:block;border-radius:var(--radius-md);}
  .header__nav-list a[aria-current="page"]{background:rgba(255,107,53,0.12);}
  .header__nav-list a[aria-current="page"]::after{display:none;}
  .header__toggle{display:flex;}
  .header__cta{font-size:0.8rem;padding:0.4rem 1rem;}

  .footer__inner{grid-template-columns:1fr;gap:var(--gap-lg);}
  .footer__columns{grid-column:1;grid-template-columns:repeat(3,1fr);}
  .footer__info{flex-direction:column;text-align:center;gap:var(--gap-sm);}

  .grid-2,.grid-3,.grid-4{grid-template-columns:1fr;}
  .grid-2-sm{grid-template-columns:1fr 1fr;}
}

@media(max-width:600px){
  :root{--header-height:56px;--gap-lg:1.2rem;--gap-xl:2.5rem;}
  .header__inner{padding:0 var(--gap-md);}
  .header__logo-text{font-size:1.1rem;}
  .header__logo-subtext{font-size:0.55rem;}
  .header__cta{font-size:0.7rem;padding:0.3rem 0.9rem;clip-path:polygon(6px 0,100% 0,calc(100% - 6px) 100%,0 100%);}
  .footer__inner{padding:var(--gap-lg) var(--gap-md);}
  .footer__columns{grid-template-columns:1fr;gap:var(--gap-md);}
  .panel-corner{clip-path:polygon(12px 0,100% 0,calc(100% - 12px) 100%,0 100%);padding:var(--gap-md);}
  .divider-slash{width:80px;}
  [data-back-to-top]{bottom:1.2rem;right:1.2rem;width:42px;height:42px;}
}

/* ===== ACCESSIBILITY / MOTION ===== */
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:0.01ms!important;animation-iteration-count:1!important;transition-duration:0.01ms!important;}
  html{scroll-behavior:auto;}
  .header__nav{transition:none;}
  [data-progress-bar]::after{transition:none;}
  [data-back-to-top]{transition:none;}
}