/* === RESET === */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{min-height:100vh;line-height:1.6;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
ul{list-style:none}
a{text-decoration:none;color:inherit}
button{cursor:pointer;font:inherit;color:inherit;border:none;background:none}
input,textarea{font:inherit}
:focus-visible{outline:3px solid var(--color-accent);outline-offset:2px;border-radius:4px}

/* === CSS VARIABLES === */
:root{
  --color-primary:#FF6600;
  --color-primary-variant:#E65C00;
  --color-secondary:#1A1A2E;
  --color-accent:#00B4D8;
  --color-bg-light:#F5F5F5;
  --color-bg-dark:#16213E;
  --color-surface:#FFFFFF;
  --color-text-primary:#FFFFFF;
  --color-text-secondary:#B0B0B0;
  --color-text-on-dark:#FFFFFF;
  --color-text-on-light:#1A1A2E;
  --color-success:#28A745;
  --color-warning:#FFC107;
  --color-error:#DC3545;
  --color-info:#17A2B8;
  --font-primary:'Noto Sans SC','PingFang SC','Microsoft YaHei',sans-serif;
  --font-secondary:'Noto Sans SC',sans-serif;
  --radius-sm:8px;
  --radius-md:16px;
  --radius-lg:24px;
  --radius-xl:32px;
  --radius-capsule:9999px;
  --shadow-sm:0 2px 8px rgba(0,0,0,0.12);
  --shadow-md:0 6px 24px rgba(0,0,0,0.16);
  --shadow-lg:0 12px 40px rgba(0,0,0,0.24);
  --transition-fast:0.2s ease;
  --transition-base:0.3s ease;
  --transition-slow:0.5s ease;
  --max-width:1200px;
  --header-height:72px;
  --z-header:100;
  --z-skip:200;
  --z-progress:150;
  --z-backtop:90;
}

/* === TYPOGRAPHY === */
body{font-family:var(--font-primary);font-weight:400;font-size:16px;line-height:1.6;color:var(--color-text-on-light);background:var(--color-bg-light)}
h1,h2,h3,h4{font-family:var(--font-secondary);font-weight:700;line-height:1.2}
h1{font-size:2.25rem;line-height:1.2}  /* 36px */
h2{font-size:1.75rem;line-height:1.3}  /* 28px */
h3{font-size:1.375rem;line-height:1.4} /* 22px */
h4{font-size:1.125rem;line-height:1.5} /* 18px */
small,.text-small{font-size:0.875rem;line-height:1.5}
.text-meta{font-size:0.875rem;color:var(--color-text-secondary)}
@media(min-width:768px){
  h1{font-size:2.5rem}  /* 40px */
  h2{font-size:2rem}    /* 32px */
  h3{font-size:1.5rem}  /* 24px */
  h4{font-size:1.25rem} /* 20px */
}

/* === SKIP LINK === */
.skip-link{position:fixed;top:-100%;left:1rem;padding:0.75rem 1.5rem;background:var(--color-primary);color:#fff;font-weight:700;border-radius:var(--radius-capsule);z-index:var(--z-skip);transition:top var(--transition-fast)}
.skip-link:focus{top:1rem}

/* === CONTAINER === */
.container{width:100%;max-width:var(--max-width);margin:0 auto;padding:0 1.25rem}
@media(min-width:768px){.container{padding:0 2rem}}

/* === SECTION === */
.section{padding:2.5rem 0}
@media(min-width:768px){.section{padding:4rem 0}}

/* === HEADER === */
.site-header{position:sticky;top:1rem;z-index:var(--z-header);padding:0 1.25rem;transition:all var(--transition-base)}
.header-inner{display:flex;align-items:center;justify-content:space-between;background:var(--color-secondary);border-radius:var(--radius-xl);padding:0.5rem 1rem;box-shadow:var(--shadow-lg);max-width:var(--max-width);margin:0 auto;min-height:var(--header-height);border:1px solid rgba(255,102,0,0.15)}
.brand{display:flex;align-items:center;gap:0.5rem;flex-shrink:0}
.brand-icon{font-size:1.75rem;line-height:1;filter:drop-shadow(0 0 6px rgba(255,102,0,0.5))}
.brand-text{font-size:1.375rem;font-weight:700;color:var(--color-primary);letter-spacing:0.02em}
.nav-capsule{display:none}
.nav-capsule[data-open]{display:block;position:absolute;top:calc(100% + 0.5rem);left:1rem;right:1rem;background:var(--color-secondary);border-radius:var(--radius-lg);padding:1rem;box-shadow:var(--shadow-md);border:1px solid rgba(255,102,0,0.15)}
.nav-list{display:flex;flex-direction:column;gap:0.25rem}
.nav-link{display:block;padding:0.625rem 1.25rem;border-radius:var(--radius-capsule);font-weight:500;font-size:0.9375rem;color:var(--color-text-secondary);transition:all var(--transition-fast);white-space:nowrap;text-align:center}
.nav-link:hover,.nav-link:focus-visible{color:var(--color-text-primary);background:rgba(255,102,0,0.12)}
.nav-link[aria-current="page"]{color:var(--color-primary);background:rgba(255,102,0,0.15);font-weight:700}
.header-actions{display:flex;align-items:center;gap:0.625rem;flex-shrink:0}
.search-trigger{width:40px;height:40px;display:flex;align-items:center;justify-content:center;border-radius:var(--radius-capsule);color:var(--color-text-secondary);transition:all var(--transition-fast)}
.search-trigger:hover,.search-trigger:focus-visible{color:var(--color-primary);background:rgba(255,102,0,0.1)}
.btn-download{display:none}
.nav-toggle{width:40px;height:40px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:4px;border-radius:var(--radius-capsule);transition:all var(--transition-fast)}
.nav-toggle:hover,.nav-toggle:focus-visible{background:rgba(255,102,0,0.1)}
.nav-toggle-line{display:block;width:22px;height:2.5px;background:var(--color-text-primary);border-radius:2px;transition:all var(--transition-fast)}
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1){transform:translateY(6.5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3){transform:translateY(-6.5px) rotate(-45deg)}
@media(min-width:768px){
  .site-header{top:1.25rem;padding:0 2rem}
  .header-inner{padding:0.5rem 1.5rem;border-radius:var(--radius-xl)}
  .nav-capsule{display:flex !important;position:static !important;background:transparent;padding:0;box-shadow:none;border:none}
  .nav-list{flex-direction:row;gap:0.125rem}
  .nav-link{padding:0.5rem 1.125rem;font-size:0.9375rem}
  .btn-download{display:inline-flex}
  .nav-toggle{display:none}
  .search-trigger{width:36px;height:36px}
}
@media(min-width:1024px){
  .nav-link{padding:0.5rem 1.25rem;font-size:1rem}
}

/* === BUTTONS === */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:0.5rem;padding:0.625rem 1.5rem;border-radius:var(--radius-capsule);font-weight:600;font-size:0.9375rem;line-height:1.4;transition:all var(--transition-fast);white-space:nowrap}
.btn:hover,.btn:focus-visible{transform:translateY(-1px);box-shadow:var(--shadow-sm)}
.btn-primary{background:var(--color-primary);color:#fff}
.btn-primary:hover,.btn-primary:focus-visible{background:var(--color-primary-variant);box-shadow:0 4px 20px rgba(255,102,0,0.35)}
.btn-accent{background:var(--color-accent);color:#fff}
.btn-accent:hover,.btn-accent:focus-visible{background:#0098b8;box-shadow:0 4px 20px rgba(0,180,216,0.35)}
.btn-outline{border:2px solid var(--color-primary);color:var(--color-primary);background:transparent}
.btn-outline:hover,.btn-outline:focus-visible{background:var(--color-primary);color:#fff}
.btn-sm{padding:0.4375rem 1rem;font-size:0.8125rem}

/* === CARD === */
.card{background:var(--color-surface);border-radius:var(--radius-lg);padding:1.5rem;box-shadow:var(--shadow-sm);transition:all var(--transition-base)}
.card:hover{box-shadow:var(--shadow-md);transform:translateY(-2px)}
.card--dark{background:var(--color-bg-dark);color:var(--color-text-on-dark)}
.card--accent{border-left:4px solid var(--color-primary)}

/* === BENTO GRID === */
.bento-grid{display:grid;grid-template-columns:1fr;gap:1.25rem}
@media(min-width:640px){.bento-grid{grid-template-columns:repeat(2,1fr)}}
@media(min-width:1024px){.bento-grid{grid-template-columns:repeat(3,1fr);grid-auto-rows:auto}}
.bento-item{border-radius:var(--radius-lg);overflow:hidden;background:var(--color-surface);box-shadow:var(--shadow-sm);transition:all var(--transition-base)}
.bento-item:hover{box-shadow:var(--shadow-md);transform:translateY(-2px)}
.bento-item--wide{grid-column:span 1}
.bento-item--tall{grid-row:span 1}
@media(min-width:640px){.bento-item--wide{grid-column:span 2}}
@media(min-width:1024px){.bento-item--tall{grid-row:span 2}}

/* === TAG / CAPSULE === */
.tag-capsule{display:inline-flex;align-items:center;padding:0.25rem 1rem;border-radius:var(--radius-capsule);font-size:0.8125rem;font-weight:500;background:rgba(255,102,0,0.12);color:var(--color-primary)}
.tag-capsule--accent{background:rgba(0,180,216,0.12);color:var(--color-accent)}
.tag-capsule--dark{background:rgba(26,26,46,0.08);color:var(--color-secondary)}

/* === FOOTER === */
.site-footer{background:var(--color-secondary);color:var(--color-text-on-dark);padding:3rem 1.25rem 1.5rem;margin-top:3rem}
.footer-inner{max-width:var(--max-width);margin:0 auto;display:grid;grid-template-columns:1fr;gap:2rem}
.footer-brand{display:flex;flex-direction:column;align-items:flex-start;gap:0.5rem}
.footer-brand .brand-icon{font-size:2rem}
.footer-brand .brand-text{font-size:1.5rem;color:var(--color-primary)}
.footer-slogan{font-size:0.9375rem;color:var(--color-text-secondary);letter-spacing:0.06em}
.footer-links{display:flex;flex-direction:column;gap:0.75rem}
.footer-link{color:var(--color-text-secondary);font-size:0.9375rem;transition:color var(--transition-fast);padding:0.25rem 0}
.footer-link:hover,.footer-link:focus-visible{color:var(--color-primary)}
.footer-contact{display:flex;flex-direction:column;gap:0.5rem}
.footer-contact-item{font-size:0.875rem;color:var(--color-text-secondary);line-height:1.6}
.footer-bottom{padding-top:1.5rem;border-top:1px solid rgba(255,255,255,0.08);display:flex;flex-direction:column;gap:0.5rem;align-items:flex-start;grid-column:1 / -1}
.footer-icp{font-size:0.8125rem;color:var(--color-text-secondary)}
.footer-copyright{font-size:0.8125rem;color:var(--color-text-secondary)}
@media(min-width:640px){
  .footer-inner{grid-template-columns:1fr 1fr;gap:2.5rem}
  .footer-brand{grid-column:1 / -1}
  .footer-bottom{flex-direction:row;justify-content:space-between;align-items:center}
}
@media(min-width:1024px){
  .footer-inner{grid-template-columns:2fr 1fr 1fr;gap:3rem}
  .footer-brand{grid-column:1}
  .footer-bottom{grid-column:1 / -1}
}

/* === PROGRESS BAR === */
.progress-bar{position:fixed;top:0;left:0;width:100%;height:3px;background:rgba(255,102,0,0.15);z-index:var(--z-progress);pointer-events:none}
.progress-bar-fill{height:100%;width:0%;background:linear-gradient(90deg,var(--color-primary),var(--color-accent));border-radius:0 2px 2px 0;transition:width 0.1s linear}

/* === BACK TO TOP === */
.back-to-top{position:fixed;bottom:2rem;right:2rem;width:48px;height:48px;border-radius:50%;background:var(--color-primary);color:#fff;display:flex;align-items:center;justify-content:center;box-shadow:var(--shadow-md);opacity:0;visibility:hidden;transform:translateY(12px);transition:all var(--transition-base);z-index:var(--z-backtop)}
.back-to-top.visible{opacity:1;visibility:visible;transform:translateY(0)}
.back-to-top:hover,.back-to-top:focus-visible{background:var(--color-primary-variant);transform:translateY(-2px);box-shadow:var(--shadow-lg)}

/* === REVEAL ANIMATION === */
[data-reveal]{opacity:0;transform:translateY(24px);transition:opacity 0.6s ease,transform 0.6s ease}
[data-reveal].revealed{opacity:1;transform:translateY(0)}
[data-reveal-left]{opacity:0;transform:translateX(-30px);transition:opacity 0.6s ease,transform 0.6s ease}
[data-reveal-left].revealed{opacity:1;transform:translateX(0)}
[data-reveal-right]{opacity:0;transform:translateX(30px);transition:opacity 0.6s ease,transform 0.6s ease}
[data-reveal-right].revealed{opacity:1;transform:translateX(0)}
[data-reveal-scale]{opacity:0;transform:scale(0.94);transition:opacity 0.6s ease,transform 0.6s ease}
[data-reveal-scale].revealed{opacity:1;transform:scale(1)}

/* === REDUCED 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}
  [data-reveal],[data-reveal-left],[data-reveal-right],[data-reveal-scale]{opacity:1;transform:none;transition:none}
  .back-to-top{transition:none}
}

/* === UTILITY === */
.text-primary{color:var(--color-primary)}
.text-accent{color:var(--color-accent)}
.text-center{text-align:center}
.flex-center{display:flex;align-items:center;justify-content:center}
.gap-1{gap:0.5rem}
.gap-2{gap:1rem}
.gap-3{gap:1.5rem}
.mt-1{margin-top:0.5rem}
.mt-2{margin-top:1rem}
.mt-3{margin-top:1.5rem}
.mb-2{margin-bottom:1rem}
.mb-3{margin-bottom:1.5rem}

/* === RESPONSIVE IMAGE CONTAINER === */
.img-container{position:relative;overflow:hidden;border-radius:var(--radius-md);background:var(--color-bg-dark)}
.img-container img{width:100%;height:100%;object-fit:cover}
.img-container--16x9{padding-bottom:56.25%}
.img-container--4x3{padding-bottom:75%}
.img-container--1x1{padding-bottom:100%}
.img-container img{position:absolute;top:0;left:0;width:100%;height:100%}
.img-container .img-placeholder{position:absolute;top:0;left:0;width:100%;height:100%;display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,var(--color-secondary),var(--color-primary-variant));color:var(--color-text-secondary);font-size:0.875rem}

/* === RESPONSIVE === */
@media(max-width:639px){
  :root{--header-height:64px}
  .btn-download{padding:0.5rem 1rem;font-size:0.8125rem}
  .section{padding:1.5rem 0}
  .card{padding:1.25rem}
}
@media(min-width:640px)and(max-width:1023px){
  .header-inner{padding:0.5rem 1.25rem}
}