.gnb{position:fixed;top:0;left:0;right:0;z-index:100;height:var(--header-h);background:rgba(15,15,26,.85);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--color-border)}.gnb__inner{max-width:1200px;margin:0 auto;height:100%;padding:0 2rem;display:flex;align-items:center;gap:2.5rem}.gnb__logo{display:flex;align-items:center;gap:.6rem;flex-shrink:0}.gnb__logo-icon{width:28px;height:28px}.gnb__logo-text{font-family:var(--font-sans);font-size:1.1rem;font-weight:700;letter-spacing:-.03em}.gnb__logo-cs{color:var(--color-text)}.gnb__logo-flow{color:var(--color-purple)}.gnb__nav{display:flex;align-items:center;gap:.25rem;margin-left:auto}.gnb__nav-item{padding:.4rem .75rem;border-radius:var(--radius-sm);font-size:.875rem;color:var(--color-text-sub);transition:color var(--transition),background var(--transition)}.gnb__nav-item:hover{color:var(--color-text);background:var(--color-purple-dim)}.gnb__nav-item--active{color:var(--color-purple);background:var(--color-purple-dim)}.gnb__hamburger{display:none;flex-direction:column;gap:5px;margin-left:auto;padding:.4rem}.gnb__hamburger-line{display:block;width:22px;height:2px;background:var(--color-text-sub);border-radius:2px;transition:transform var(--transition),opacity var(--transition)}.gnb__hamburger--open .gnb__hamburger-line:first-child{transform:translateY(7px) rotate(45deg)}.gnb__hamburger--open .gnb__hamburger-line:nth-child(2){opacity:0}.gnb__hamburger--open .gnb__hamburger-line:nth-child(3){transform:translateY(-7px) rotate(-45deg)}.gnb__drawer{display:none;flex-direction:column;background:var(--color-surface);border-bottom:1px solid var(--color-border);padding:.75rem 1.5rem}.gnb__drawer--open{display:flex}.gnb__drawer-item{padding:.75rem .5rem;font-size:.9rem;color:var(--color-text-sub);border-bottom:1px solid var(--color-border);transition:color var(--transition)}.gnb__drawer-item:last-child{border-bottom:none}.gnb__drawer-item--active,.gnb__drawer-item:hover{color:var(--color-purple)}@media (max-width:768px){.gnb__nav{display:none}.gnb__hamburger{display:flex;margin-left:auto;order:1}.gnb__search-btn{order:2}.gnb__theme-btn{order:2;margin-left:.5rem}}[data-theme=light] .gnb{background:rgba(245,245,255,.92);border-bottom-color:rgba(108,99,255,.18)}[data-theme=light] .gnb__drawer{background:var(--color-surface)}[data-theme=light] .gnb__hamburger-line{background:var(--color-text-sub)}.gnb__search-btn,.gnb__study-btn,.gnb__theme-btn{display:flex;align-items:center;justify-content:center;width:34px;height:34px;border-radius:50%;background:0 0;border:1px solid var(--color-border);color:var(--color-text-sub);cursor:pointer;flex-shrink:0;transition:border-color var(--transition),color var(--transition),background var(--transition)}.gnb__search-btn:hover,.gnb__study-btn.is-active,.gnb__study-btn:hover,.gnb__theme-btn:hover{border-color:var(--color-purple);color:var(--color-purple);background:var(--color-purple-dim)}.gnb__search-btn svg,.gnb__study-btn svg,.gnb__theme-btn svg{width:16px;height:16px;flex-shrink:0}.gnb__search-btn,.gnb__study-btn{margin-right:-1.75rem;text-decoration:none}@media (max-width:768px){.gnb__study-btn{display:none}}.gnb__theme-icon--dark{display:block}.gnb__theme-icon--light{display:none}[data-theme=light] .gnb__theme-icon--dark{display:none}[data-theme=light] .gnb__theme-icon--light{display:block}.gnb__logo-icon--dark{display:block}.gnb__logo-icon--light{display:none}[data-theme=light] .gnb__logo-icon--dark{display:none}[data-theme=light] .gnb__logo-icon--light{display:block}[data-theme=light] .topic-tabs{background:rgba(245,245,255,.95);border-bottom-color:rgba(108,99,255,.18)}[data-theme=light] .visualizer-canvas-area{background:var(--color-surface);border-color:rgba(108,99,255,.2)}