:root {
    --bg: #070b14;
    --bg-card: #0d1420;
    --border: #1c2536;
    --cyan: #38e0f5;
    --purple: #a78bfa;
    --pink: #f472b6;
    --green: #4ade80;
    --red: #f87171;
    --text: #cbd5e1;
    --text-dim: #64748b;
}

* { box-sizing: border-box; }

html, body {
    margin: 0;
    min-height: 100%;
    background: var(--bg);
    color: var(--text);
    font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
}

/* 网格背景 */
body {
    background-image:
        linear-gradient(rgba(56, 224, 245, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(56, 224, 245, 0.05) 1px, transparent 1px);
    background-size: 42px 42px;
    position: relative;
    overflow-x: hidden;
}

/* 跟随鼠标的光晕 */
#spotlight {
    position: fixed;
    top: 0; left: 0;
    width: 100vw; height: 100vh;
    pointer-events: none;
    z-index: 0;
    background: radial-gradient(600px circle at var(--mx, 50%) var(--my, 50%),
        rgba(56, 224, 245, 0.07), transparent 70%);
    transition: background 0.05s ease-out;
}

.page-wrap { position: relative; z-index: 1; }

nav.topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 18px 40px;
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(6px);
}
nav.topbar .brand {
    display: flex; align-items: center; gap: 10px;
    font-weight: 800; font-size: 18px; color: #fff;
}
nav.topbar .brand .badge-icon {
    width: 34px; height: 34px; border-radius: 9px;
    display: flex; align-items: center; justify-content: center;
    background: linear-gradient(135deg, var(--cyan), var(--purple));
}
nav.topbar .links { display: flex; gap: 26px; align-items: center; }
nav.topbar a { color: var(--text); text-decoration: none; font-size: 14px; }
nav.topbar a:hover { color: var(--cyan); }
nav.topbar .pill {
    border: 1px solid var(--border); border-radius: 999px;
    padding: 6px 14px; font-size: 12px; color: var(--text-dim);
}

.container { max-width: 960px; margin: 0 auto; padding: 60px 24px; }
.container.narrow { max-width: 720px; }

.hero { text-align: center; margin-bottom: 56px; }
.hero h1 {
    font-size: 44px; font-weight: 900; margin: 0 0 14px 0;
    background: linear-gradient(90deg, var(--cyan), var(--purple));
    -webkit-background-clip: text; background-clip: text; color: transparent;
    letter-spacing: 1px;
}
.hero p { color: var(--text-dim); font-size: 15px; }
.hero .divider {
    width: 90px; height: 3px; margin: 22px auto;
    background: linear-gradient(90deg, var(--cyan), var(--purple));
    border-radius: 3px;
}
.eyebrow {
    display: inline-block; font-size: 12px; letter-spacing: 2px;
    color: var(--cyan); border: 1px solid rgba(56,224,245,.3);
    padding: 5px 16px; border-radius: 999px; margin-bottom: 16px;
}

.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 22px; }

.chal-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 28px 24px;
    text-decoration: none;
    color: var(--text);
    display: block;
    position: relative;
    overflow: hidden;
    transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.chal-card::before {
    content: "";
    position: absolute; inset: 0; border-radius: 16px; padding: 1px;
    background: linear-gradient(135deg, var(--cyan), var(--purple), var(--pink));
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor; mask-composite: exclude;
    opacity: 0; transition: opacity .25s ease;
}
.chal-card:hover {
    transform: translateY(-6px) scale(1.015);
    box-shadow: 0 18px 40px -12px rgba(56, 224, 245, 0.25);
}
.chal-card:hover::before { opacity: 1; }
.chal-card .lv {
    position: absolute; top: 20px; right: 22px;
    font-size: 11px; letter-spacing: 1px; color: var(--text-dim);
}
.chal-card .icon {
    width: 46px; height: 46px; margin-bottom: 18px;
    display: flex; align-items: center; justify-content: center;
    border-radius: 12px; background: rgba(56,224,245,.08);
}
.chal-card h3 { margin: 0 0 8px 0; font-size: 18px; color: #fff; }
.chal-card p { margin: 0; font-size: 13px; color: var(--text-dim); line-height: 1.6; }
.chal-card .go {
    margin-top: 18px; font-size: 13px; color: var(--cyan);
    display: flex; align-items: center; gap: 6px;
}

.panel {
    background: var(--bg-card); border: 1px solid var(--border);
    border-radius: 14px; padding: 26px 28px; margin-bottom: 22px;
}
.panel h2 { margin-top: 0; font-size: 16px; color: #fff; }

input[type=text], input[type=password] {
    width: 100%; padding: 10px 12px; margin: 6px 0 16px 0;
    border-radius: 8px; border: 1px solid var(--border);
    background: #0a0f1a; color: var(--text); font-size: 14px;
    outline: none; transition: border-color .2s;
}
input[type=text]:focus, input[type=password]:focus { border-color: var(--cyan); }
label { font-size: 13px; color: var(--text-dim); }

button, .btn {
    background: linear-gradient(90deg, var(--cyan), var(--purple));
    color: #06111f; border: none; padding: 10px 22px;
    border-radius: 8px; font-weight: 700; font-size: 14px; cursor: pointer;
    transition: filter .2s, transform .2s;
}
button:hover, .btn:hover { filter: brightness(1.12); transform: translateY(-1px); }
button.ghost {
    background: transparent; border: 1px solid var(--border); color: var(--text);
}
button.ghost:hover { border-color: var(--cyan); color: var(--cyan); }

table { width: 100%; border-collapse: collapse; margin-top: 6px; }
th, td { border: 1px solid var(--border); padding: 9px 11px; text-align: left; font-size: 13px; }
th { background: #0a0f1a; color: var(--text-dim); font-weight: 600; }

pre, code {
    background: #0a0f1a; color: #fbbf24; padding: 3px 8px;
    border-radius: 6px; font-size: 13px;
}
pre { padding: 14px; overflow-x: auto; }

.tag-success { color: var(--green); }
.tag-error { color: var(--red); }
.tag-warn { color: #fbbf24; }
.text-dim { color: var(--text-dim); font-size: 13px; }

.hint-box {
    border: 1px dashed var(--border); border-radius: 10px;
    padding: 14px 16px; margin-top: 10px;
}
.hint-content {
    display: none; margin-top: 10px; font-size: 13px; color: var(--text);
    animation: fadeIn .3s ease;
}
.hint-content.show { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(-4px); } to { opacity: 1; transform: translateY(0); } }

.flag-box { display: flex; gap: 10px; margin-top: 8px; }
.flag-box input { flex: 1; margin: 0; }
.flag-result { margin-top: 12px; font-size: 14px; min-height: 20px; }
.shake { animation: shake .4s; }
@keyframes shake {
    0%,100% { transform: translateX(0); }
    20%,60% { transform: translateX(-6px); }
    40%,80% { transform: translateX(6px); }
}
.pop { animation: pop .4s; }
@keyframes pop {
    0% { transform: scale(.9); opacity: 0; }
    60% { transform: scale(1.03); }
    100% { transform: scale(1); opacity: 1; }
}