/* ===== 数对与坐标定位练习 ===== */
#gcApp .gc-hero { text-align: center; padding: 12px 10px 0; }
#gcApp .gc-hero h1 { font-size: 30px; font-weight: 800; color: var(--c-text); margin-bottom: 10px; }
#gcApp .gc-hero p { font-size: 15px; color: var(--c-text-sub); line-height: 1.7; }

#gcApp .gc-bar { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin: 18px 0; }
#gcApp .gc-tab {
    border: 2px solid var(--c-primary); background: transparent; color: var(--c-primary);
    border-radius: 999px; padding: 8px 16px; font-size: 14px; font-weight: 700;
    cursor: pointer; transition: background .15s, color .15s;
}
#gcApp .gc-tab.is-on { background: var(--c-primary); color: #fff; }
#gcApp .gc-tab.gray { border-color: var(--c-border); color: var(--c-text-sub); }
#gcApp .gc-tab.gray.is-on { background: var(--c-text-sub); color: #fff; border-color: var(--c-text-sub); }

#gcApp .gc-panel {
    max-width: 660px; margin: 0 auto; background: var(--c-surface);
    border: 1px solid var(--c-border); border-radius: var(--radius-md);
    padding: 20px 16px; box-shadow: var(--shadow-md);
}
#gcApp .gc-q { text-align: center; font-size: 18px; font-weight: 800; color: var(--c-text); line-height: 1.7; margin-bottom: 16px; }
#gcApp .gc-q b { color: var(--c-primary); font-size: 22px; }

#gcApp .gc-board { max-width: 480px; margin: 0 auto; }
#gcApp .gc-grid { display: grid; gap: 5px; }
#gcApp .gc-lab {
    display: flex; align-items: center; justify-content: center;
    font-size: 13px; font-weight: 800; color: var(--c-text-muted);
}
#gcApp .gc-cell {
    aspect-ratio: 1 / 1; border: 2px solid var(--c-border); border-radius: 8px;
    background: var(--c-surface-soft); cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    font-size: 22px; transition: background .15s, border-color .15s;
}
#gcApp .gc-cell:hover { border-color: var(--c-primary); background: var(--c-primary-soft); }
#gcApp .gc-cell.is-target { background: var(--c-primary-soft); border-color: var(--c-primary); }
#gcApp .gc-cell.ok { background: var(--c-primary-soft); border-color: var(--c-accent-green); }
#gcApp .gc-cell.bad { background: #fff0f0; border-color: #e03131; }
#gcApp .gc-axis { text-align: center; font-size: 12px; font-weight: 700; color: var(--c-text-muted); margin-top: 6px; }

#gcApp .gc-fill { text-align: center; margin-top: 18px; display: none; gap: 10px; justify-content: center; flex-wrap: wrap; }
#gcApp .gc-fill.show { display: flex; }
#gcApp .gc-slot { display: flex; flex-direction: column; align-items: center; gap: 6px; }
#gcApp .gc-slot label { font-size: 13px; font-weight: 700; color: var(--c-text-muted); }
#gcApp .gc-in {
    width: 74px; height: 58px; border: 2px solid var(--c-primary); border-radius: 14px;
    background: var(--c-surface-soft); color: var(--c-primary);
    font-size: 24px; font-weight: 800; text-align: center; outline: none;
}
#gcApp .gc-in.ok { border-color: var(--c-accent-green); background: var(--c-primary-soft); }
#gcApp .gc-in.bad { border-color: #e03131; background: #fff0f0; color: #e03131; }

#gcApp .gc-msg { text-align: center; font-size: 17px; font-weight: 800; min-height: 26px; margin-top: 14px; color: var(--c-text); }
#gcApp .gc-msg.ok { color: var(--c-primary); }
#gcApp .gc-msg.bad { color: #e03131; }

#gcApp .gc-ctrl { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-top: 18px; }
#gcApp .gc-btn {
    border: none; border-radius: 999px; padding: 12px 20px; font-size: 15px; font-weight: 700;
    color: #fff; cursor: pointer; background: linear-gradient(135deg, var(--c-primary), var(--c-accent-cyan));
    box-shadow: var(--shadow-md);
}
#gcApp .gc-btn.gray { background: var(--c-surface-2); color: var(--c-text); box-shadow: none; border: 1px solid var(--c-border); }
#gcApp .gc-btn:disabled { opacity: .5; cursor: default; }

#gcApp .gc-stat {
    max-width: 660px; margin: 18px auto 0; background: var(--c-surface);
    border: 1px solid var(--c-border); border-radius: var(--radius-md);
    padding: 14px 18px; box-shadow: var(--shadow-md); text-align: center;
    font-size: 14px; line-height: 1.9; color: var(--c-text-sub);
}
#gcApp .gc-stat b { color: var(--c-primary); font-size: 18px; }

#gcApp .gc-ai, #gcApp .gc-info { max-width: 700px; margin: 30px auto 0; }
#gcApp .gc-ai h2, #gcApp .gc-info h2 { font-size: 20px; font-weight: 800; color: var(--c-text); margin-bottom: 10px; }
#gcApp .gc-ai p { font-size: 14px; color: var(--c-text-sub); line-height: 1.8; margin-bottom: 14px; }
#gcApp .gc-ai-row { display: flex; gap: 10px; flex-wrap: wrap; }
#gcApp .gc-out {
    margin-top: 14px; background: var(--c-surface-soft); border: 1px solid var(--c-border);
    border-radius: var(--radius-sm); padding: 16px 18px;
    font-size: 15px; line-height: 1.85; color: var(--c-text); white-space: pre-wrap;
}
#gcApp .gc-info ul { list-style: disc; padding-left: 22px; margin-bottom: 24px; }
#gcApp .gc-info li { font-size: 14px; line-height: 1.9; color: var(--c-text-sub); margin-bottom: 8px; }
#gcApp .gc-info li b { color: var(--c-text); }

@media (max-width: 560px) {
    #gcApp .gc-hero h1 { font-size: 24px; }
    #gcApp .gc-cell { font-size: 18px; }
}