/* ===== RESET ===== */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}

/* ===== THEME ===== */
:root,[data-theme="dark"]{
  --bg-primary:#0a0a0a;
  --bg-secondary:#111111;
  --bg-card:#1a1a1a;
  --accent:#00d4aa;
  --accent-dim:#0f4c5c;
  --accent-glow:rgba(0,212,170,.15);
  --text-primary:#f0f0f0;
  --text-secondary:#888888;
  --border:#2a2a2a;
  --nav-bg:rgba(10,10,10,.88);
  --r:8px;
  --ff:'IBM Plex Sans',system-ui,sans-serif;
  --mono:'IBM Plex Mono',monospace;
  --nav-h:56px;
}
[data-theme="light"]{
  --bg-primary:#ffffff;
  --bg-secondary:#f5f6f7;
  --bg-card:#ffffff;
  --accent:#009e7e;
  --accent-dim:#b8e6d9;
  --accent-glow:rgba(0,158,126,.08);
  --text-primary:#1a1a1a;
  --text-secondary:#5a5a5a;
  --border:#e0e0e0;
  --nav-bg:rgba(255,255,255,.88);
}

html,body{
  min-height:100%;
  font-family:var(--ff);
  color:var(--text-primary);
  background:var(--bg-primary);
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
a{color:var(--accent);text-decoration:none}
a:hover{color:var(--accent)}
a[href]::after{
  content:'';display:inline-block;
  width:1.2em;height:1.2em;margin-left:.2em;vertical-align:middle;
  background:currentColor;opacity:.45;
  -webkit-mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
  mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
  -webkit-mask-size:contain;mask-size:contain;
  -webkit-mask-repeat:no-repeat;mask-repeat:no-repeat;
}
.top-nav a::after,
.blog-footer a::after{content:none !important}
img{max-width:100%;display:block}
button{cursor:pointer;font-family:var(--ff)}

/* ===== TOP NAV ===== */
.top-nav{
  position:fixed;top:0;left:0;right:0;
  height:var(--nav-h);
  background:var(--nav-bg);
  backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);
  z-index:200;
  display:flex;align-items:center;padding:0 2rem;
  border-bottom:1px solid var(--border);
}
.top-nav .brand{
  font-weight:700;font-size:.9rem;color:var(--text-primary);
  letter-spacing:.04em;text-transform:uppercase;margin-right:auto;
}
.nav-link{
  font-size:.73rem;font-weight:500;color:var(--text-secondary);
  letter-spacing:.03em;text-transform:uppercase;margin-right:1.2rem;
}
.nav-link:hover,.nav-link.active{color:var(--accent)}
.nav-link.active::after{
  content:'';position:absolute;bottom:-4px;left:0;right:0;
  height:2px;background:var(--accent);border-radius:1px;
}
.theme-toggle{
  background:none;border:1px solid var(--border);
  color:var(--text-secondary);
  width:36px;height:36px;border-radius:50%;font-size:1.05rem;
  display:flex;align-items:center;justify-content:center;
  transition:border-color .2s,color .2s;
}
.theme-toggle:hover{border-color:var(--accent);color:var(--accent)}

/* ===== BLOG MAIN ===== */
.blog-main{
  max-width:760px;margin:0 auto;
  padding:calc(var(--nav-h) + 3rem) 2rem 4rem;
}
.blog-header{margin-bottom:2.5rem}
.sec-title{
  font-size:1.3rem;font-weight:700;
  color:var(--accent);letter-spacing:-.01em;margin-bottom:.3rem;
}
.sec-subtitle{font-size:.88rem;color:var(--text-secondary)}

/* ===== BLOG LIST ===== */
.blog-list{display:flex;flex-direction:column;gap:1rem}
.blog-card{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:12px;padding:1.6rem;
  display:block;text-decoration:none;transition:border-color .2s;
}
.blog-card:hover{border-color:var(--accent-dim)}
.blog-tag{
  display:inline-block;background:var(--accent-glow);color:var(--accent);
  font-size:.66rem;font-weight:600;padding:.18rem .65rem;border-radius:4px;
  letter-spacing:.06em;font-family:var(--mono);margin-bottom:.6rem;
}
.blog-card h2{font-size:1.1rem;font-weight:700;color:var(--text-primary);margin-bottom:.4rem}
.blog-card h2 a{color:inherit;text-decoration:none}
.blog-card:hover h2 a{color:var(--accent)}
.blog-excerpt{font-size:.84rem;color:var(--text-secondary);line-height:1.7;margin-bottom:.8rem}

/* ===== FOOTER ===== */
.blog-footer{
  text-align:center;padding:2rem;
  font-size:.73rem;color:var(--text-secondary);
  border-top:1px solid var(--border);
}
.blog-footer a{color:var(--accent)}

/* ===== RESPONSIVE ===== */
@media(max-width:768px){
  .sec-title{font-size:1.1rem}
  .blog-main{padding:calc(var(--nav-h) + 2rem) 1.2rem 3rem}
}