:root {
  --bg: #05060f;
  --bg2: #0b1026;
  --panel: #121a33;
  --panel2: #1a2342;
  --text: #e8ecff;
  --muted: #9fb0d8;
  --accent: #5b8cff;
  --accent2: #b06bff;
  --red: #ff5b6e;
  --green: #38e08b;
  --border: #2a3566;
}

* { box-sizing: border-box; }

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

body {
  min-height: 100vh;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(120,80,255,0.18), transparent 60%),
    radial-gradient(900px 500px at 10% 110%, rgba(80,140,255,0.15), transparent 60%),
    var(--bg);
  position: relative;
}

/* 星空 */
.stars {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    radial-gradient(1px 1px at 20% 30%, #fff, transparent),
    radial-gradient(1px 1px at 70% 20%, #cfe0ff, transparent),
    radial-gradient(1px 1px at 40% 70%, #fff, transparent),
    radial-gradient(2px 2px at 85% 60%, #fff, transparent),
    radial-gradient(1px 1px at 55% 85%, #bcd  , transparent),
    radial-gradient(1px 1px at 10% 80%, #fff, transparent);
  background-repeat: repeat;
  background-size: 400px 400px;
  opacity: 0.6;
}

.wrap {
  position: relative;
  z-index: 1;
  max-width: 920px;
  margin: 0 auto;
  padding: 24px 18px 60px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 0 22px;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  font-size: 26px;
  letter-spacing: 1px;
}
.brand .logo {
  width: auto; height: 46px;
  display: block;
  filter: drop-shadow(0 0 10px rgba(90,130,255,0.45));
}
.brand small { color: var(--muted); font-weight: 500; font-size: 13px; }

.userbox { display: flex; align-items: center; gap: 10px; font-size: 14px; }
.userbox input {
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 8px 10px;
  outline: none;
}
.userbox button, .btn {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 9px 16px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
}
.btn.ghost {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px;
  margin-bottom: 14px;
}

h1, h2, h3 { margin: 0 0 10px; }
h1 { font-size: 22px; }
.sub { color: var(--muted); font-size: 14px; }

.problem {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--panel2);
  margin-bottom: 10px;
  cursor: pointer;
  transition: transform .08s, border-color .2s;
}
.problem:hover { transform: translateY(-2px); border-color: var(--accent); }
.problem .meta { color: var(--muted); font-size: 13px; margin-top: 4px; }
.tag {
  display: inline-block;
  font-size: 12px;
  color: var(--accent);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1px 7px;
  margin-right: 6px;
}
.status { font-size: 13px; font-weight: 700; }
.status.ac { color: var(--green); }
.status.wa { color: var(--red); }
.status.none { color: var(--muted); }

pre {
  background: #070b1a;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  overflow-x: auto;
  color: #cfe0ff;
  font-family: "Consolas", "Menlo", monospace;
  font-size: 14px;
  white-space: pre-wrap;
  word-break: break-all;
}

.case-row {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  margin-bottom: 12px;
  background: var(--panel2);
}
.case-row .verdict { font-weight: 700; margin-top: 8px; }
.case-row .verdict.ac { color: var(--green); }
.case-row .verdict.wa { color: var(--red); }

textarea {
  width: 100%;
  min-height: 70px;
  background: #070b1a;
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  padding: 10px;
  font-family: "Consolas", "Menlo", monospace;
  font-size: 14px;
  resize: vertical;
}

.result-banner {
  text-align: center;
  font-size: 30px;
  font-weight: 800;
  padding: 16px;
  border-radius: 12px;
  margin: 14px 0;
}
.result-banner.ac { background: rgba(56,224,139,0.12); color: var(--green); border: 1px solid var(--green); }
.result-banner.wa { background: rgba(255,91,110,0.12); color: var(--red); border: 1px solid var(--red); }

.tips {
  background: rgba(90,140,255,0.08);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  padding: 12px 14px;
  color: var(--text);
  font-size: 14px;
  white-space: pre-wrap;
}
.note { color: var(--muted); font-size: 13px; line-height: 1.7; }
.backbtn {
  display: inline-block;
  margin-bottom: 16px;
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
}
.backbtn:hover { color: var(--text); }