header { background: var(--bg2); border-bottom: 1px solid var(--border); position: sticky; top: var(--gnav-h, 0px); z-index: 100; }
.nav-top { max-width: var(--max-w); margin: 0 auto; padding: 0 20px; height: 48px; display: flex; align-items: center; gap: 12px; }
.logo { display: flex; align-items: center; font-family: var(--font); font-size: 1rem; font-weight: 700; color: var(--accent); text-decoration: none; letter-spacing: .05em; flex-shrink: 0; }
.logo:hover { opacity: .8; }
.logo-sep { color: var(--border); font-family: var(--font); font-size: .9rem; margin: 0 2px; }
.logo-sub { font-family: var(--font); font-size: .8rem; color: var(--text3); }
.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-right { margin-left: auto; display: flex; align-items: center; gap: 6px; }
.theme-btn { background: none; border: 1px solid var(--border); color: var(--text2); width: 32px; height: 32px; border-radius: 6px; cursor: pointer; display: flex; align-items: center; justify-content: center; transition: all .2s; }
.theme-btn:hover { border-color: var(--accent); color: var(--accent); }

:root {
  --font: 'Space Mono', monospace;
  --font-ko: 'Pretendard', 'Apple SD Gothic Neo', 'Noto Sans KR', sans-serif;
  --bg: #0d1117; --bg2: #161b22; --bg3: #21262d;
  --border: #30363d; --border2: #444c56;
  --text1: #e6edf3; --text2: #8b949e; --text3: #6e7681;
  --accent: #f7931a; --accent2: #e07b10;
  --green: #3fb950; --red: #f85149; --blue: #58a6ff;
  --shadow: 0 4px 20px rgba(0,0,0,0.4);
  --max-w: 1200px; --radius: 10px;
}
[data-theme="light"] {
  --bg: #f6f8fa; --bg2: #ffffff; --bg3: #eaeef2;
  --border: #d0d7de; --border2: #b8c0cc;
  --text1: #1f2328; --text2: #656d76; --text3: #8c959f;
  --accent: #bc4e00; --shadow: 0 4px 12px rgba(0,0,0,0.1);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: var(--font-ko); background: var(--bg); color: var(--text1); min-height: 100vh; }
.nav-links a { color: var(--text2); font-size: .8rem; padding: 6px 12px; border-radius: 4px; transition: all .2s; text-decoration: none; font-family: var(--font-ko); position: relative; }
.nav-links a::after { content: ''; position: absolute; bottom: -2px; left: 50%; transform: translateX(-50%); width: 0; height: 2px; background: var(--accent); border-radius: 1px; transition: width .2s; }
.nav-links a:hover { color: var(--accent); background: rgba(247,147,26,.06); }
.nav-links a.active { color: var(--accent); background: rgba(247,147,26,.08); }
.nav-links a.active::after { width: 60%; }

nav a { color: var(--text2); text-decoration: none; font-size: .82rem; font-family: var(--font-ko); transition: color .2s; }
nav a:hover, nav a.active { color: var(--accent); }
#theme-btn { background: var(--bg3); border: 1px solid var(--border); color: var(--text2); width: 32px; height: 32px; border-radius: 7px; cursor: pointer; font-size: .9rem; display: flex; align-items: center; justify-content: center; margin-left: auto; }
.hero { text-align: center; padding: 60px 20px 40px; }
.hero h1 { font-family: var(--font); font-size: 2.4rem; font-weight: 700; color: var(--text1); margin-bottom: 12px; }
.hero h1 .accent { color: var(--accent); }
.hero-sub { color: var(--text2); font-size: .95rem; font-family: var(--font-ko); }
.tools-grid { max-width: var(--max-w); margin: 0 auto; padding: 0 20px 60px; display: grid; grid-template-columns: repeat(auto-fill, minmax(480px, 1fr)); gap: 20px; }
.tool-card { background: var(--bg2); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; transition: border-color .2s; }
.tool-card:hover { border-color: var(--border2); }
.tool-icon { width: 22px; height: 22px; color: var(--accent); flex-shrink: 0; }
.tool-header { display: flex; align-items: center; gap: 8px; margin-bottom: 18px; }
.tool-header h2 { font-size: .95rem; font-weight: 600; font-family: var(--font-ko); color: var(--text1); }
.tool-input { width: 100%; background: var(--bg3); border: 1px solid var(--border); border-radius: 7px; color: var(--text1); font-family: var(--font); font-size: .8rem; padding: 10px 12px; outline: none; transition: border-color .2s; margin-bottom: 10px; }
.tool-input:focus { border-color: var(--accent); }
.tool-input.textarea { resize: vertical; }
.tool-btn { background: var(--accent); border: none; color: #000; font-family: var(--font-ko); font-weight: 700; font-size: .82rem; padding: 8px 18px; border-radius: 7px; cursor: pointer; transition: background .2s; }
.tool-btn:hover { background: var(--accent2); }
.tool-btn.sm { padding: 6px 14px; font-size: .75rem; }
.tool-btn.danger { background: var(--red); color: #fff; }
.tool-btn.danger:hover { background: #c93a2e; }
.btn-row { display: flex; gap: 8px; margin-bottom: 10px; flex-wrap: wrap; }
.tool-result { margin-top: 14px; font-family: var(--font); font-size: .78rem; color: var(--text2); background: var(--bg3); border-radius: 7px; padding: 12px; display: none; word-break: break-all; line-height: 1.7; }
.tool-result.show { display: block; }
.tool-result .ok { color: var(--green); }
.tool-result .err { color: var(--red); }
.tool-result .key { color: var(--text3); }
.tool-result .val { color: var(--text1); }
.tool-result .accent { color: var(--accent); }
.conv-row { display: grid; grid-template-columns: 90px 1fr; align-items: center; gap: 10px; margin-bottom: 8px; }
.conv-row label { font-size: .75rem; color: var(--text3); font-family: var(--font-ko); text-align: right; }
.conv-row .tool-input { margin-bottom: 0; }
.conv-price-info { font-size: .68rem; color: var(--text3); font-family: var(--font-ko); margin-top: 8px; text-align: right; }
.op-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 8px; padding: 10px; }
.op-item { background: var(--bg2); border: 1px solid var(--border); border-radius: 6px; padding: 8px 10px; }
.op-name { font-family: var(--font); font-size: .72rem; color: var(--accent); font-weight: 700; }
.op-hex { font-family: var(--font); font-size: .65rem; color: var(--text3); }
.op-desc { font-family: var(--font-ko); font-size: .68rem; color: var(--text2); margin-top: 4px; }
footer { border-top: 1px solid var(--border); padding: 20px; }
.footer-inner { max-width: var(--max-w); margin: 0 auto; display: flex; justify-content: space-between; font-size: .72rem; color: var(--text3); font-family: var(--font-ko); }
@media (max-width: 600px) { .tools-grid { grid-template-columns: 1fr; } .hero h1 { font-size: 1.8rem; } }

.lang-dropdown{position:relative;}
.lang-btn{background:none;border:1px solid var(--border);color:var(--text2);font-family:var(--font);font-size:.72rem;font-weight:700;padding:0 8px;height:32px;border-radius:6px;cursor:pointer;transition:all .2s;letter-spacing:.05em;}
.lang-btn:hover{border-color:var(--accent);color:var(--accent);}
.lang-menu{display:none;position:absolute;top:calc(100% + 6px);right:0;background:var(--bg2);border:1px solid var(--border);border-radius:8px;min-width:100px;z-index:200;box-shadow:0 8px 24px rgba(0,0,0,.4);overflow:hidden;}
.lang-menu.open{display:block;}
.lang-menu button{display:block;width:100%;text-align:left;padding:8px 14px;background:none;border:none;color:var(--text2);font-family:var(--font-ko);font-size:.78rem;cursor:pointer;transition:background .15s,color .15s;}
.lang-menu button:hover{background:var(--bg3);color:var(--accent);}

@media(max-width:768px){.appbar{display:none !important;}}

/* utility classes (migrated from inline styles) */
.icon-noshrink{flex-shrink:0}
.logo-icon{flex-shrink:0;margin-right:6px}
.inline-icon{display:inline;vertical-align:middle}
.auth-mount{position:relative;display:inline-flex}
.hidden{display:none !important}
.mt-10{margin-top:10px}
.explorer-link{color:var(--accent);text-decoration:none}
.word-break-all{word-break:break-all}
.no-results{color:var(--text3);padding:8px}
.retry-btn{margin-left:8px;padding:2px 8px;font-size:.72rem;cursor:pointer}

/* skip-link */
.skip-link{position:absolute;top:-40px;left:0;background:var(--accent);color:#fff;padding:8px 16px;z-index:1000;font-size:.8rem;font-family:var(--font-ko);transition:top .2s;text-decoration:none;border-radius:0 0 4px 0}
.skip-link:focus{top:0}

/* learn-links */
.learn-links{display:flex;align-items:center;gap:8px;flex-wrap:wrap;padding:10px 14px;background:var(--bg2);border:1px solid var(--border);border-radius:7px;margin:10px auto;max-width:var(--max-w);font-size:.78rem}
.learn-links svg{color:var(--text3);flex-shrink:0}
.learn-label{color:var(--text3);font-family:var(--font-ko);white-space:nowrap;margin-right:2px}
.learn-chip{color:var(--text2);text-decoration:none;padding:3px 10px;border:1px solid var(--border);border-radius:4px;font-family:var(--font-ko);font-size:.72rem;transition:all .15s;white-space:nowrap}
.learn-chip:hover{border-color:var(--accent);color:var(--accent)}

/* appbar */
.appbar{display:flex;flex-wrap:wrap;gap:6px;justify-content:center;padding:12px 20px;border-top:1px solid var(--border);background:var(--bg2);position:fixed;bottom:0;left:0;right:0;z-index:90;backdrop-filter:blur(10px)}
.appbar a{display:flex;flex-direction:column;align-items:center;gap:4px;padding:8px 12px;border:1px solid var(--border);border-radius:8px;text-decoration:none;color:var(--text2);font-size:.62rem;font-family:var(--font-ko);background:var(--bg3);min-width:56px;transition:all .2s}
.appbar a:hover,.appbar a.active{border-color:var(--accent);color:var(--accent)}
.appbar a svg{flex-shrink:0}
.nav-links{display:flex;gap:4px;margin-left:12px;padding-left:12px;border-left:1px solid var(--border);}
.logo-sub{display:inline-block;min-width:65px;}
.nav-links a{color:var(--text2);font-size:.78rem;padding:5px 10px;border-radius:4px;font-family:var(--font-ko);transition:all .2s;white-space:nowrap;}
.nav-links a:hover{color:var(--accent);background:rgba(247,147,26,.06);}
@media(max-width:600px){.nav-links{display:none;}}

/* ── 데스크톱/모바일 토글 ── */
.mobile-only { display: none; }
@media (max-width: 768px) {
  .desktop-only { display: none !important; }
  .mobile-only { display: block; }
}

/* ── 햄버거 메뉴 (모바일) ── */
.hamburger-wrap { position: relative; }
.hamburger-panel {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 10px;
  min-width: 200px;
  z-index: 300;
  box-shadow: 0 8px 32px rgba(0,0,0,.5);
  overflow: hidden;
}
.hamburger-panel.open { display: block; }
.settings-section { padding: 8px 6px; }
.settings-section--border { border-top: 1px solid var(--border); }
.settings-label { font-size: .68rem; color: var(--text3); font-family: var(--font-ko); padding: 2px 8px 6px; text-transform: uppercase; letter-spacing: .06em; }
.settings-lang-row { display: flex; gap: 4px; padding: 2px 8px 4px; }
.settings-lang-btn { flex: 1; background: var(--bg3); border: 1px solid var(--border); color: var(--text2); font-family: var(--font); font-size: .72rem; padding: 5px 0; border-radius: 5px; cursor: pointer; transition: all .2s; text-align: center; }
.settings-lang-btn:hover, .settings-lang-btn.active { border-color: var(--accent); color: var(--accent); background: rgba(247,147,26,.08); }
.settings-item { display: flex; align-items: center; gap: 9px; width: 100%; background: none; border: none; color: var(--text2); font-family: var(--font-ko); font-size: .78rem; padding: 7px 10px; border-radius: 6px; cursor: pointer; transition: background .15s, color .15s; text-align: left; }
.settings-item:hover { background: var(--bg3); color: var(--accent); }

/* Focus indicator for keyboard navigation (WCAG 2.1 AA) */
:focus-visible{outline:2px solid var(--accent,#f7931a);outline-offset:2px;border-radius:2px}
:focus:not(:focus-visible){outline:none}