@font-face {
    font-family: 'FandolKaiSubset';
    src: url('static/fandolkai-subset.woff2') format('woff2');
    font-display: block;
}

:root {
    --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-cjk: "PingFang SC", "PingFang TC", "Hiragino Sans GB", "Heiti SC", "Noto Sans CJK SC", serif;
    --font-kai: "FandolKaiSubset", "Kaiti SC", "STKaiti", "KaiTi", "楷体", var(--font-cjk);
    --bg:     #f5f5f7;
    --fg:     #1a1a1a;
    --fg-muted: #555;
    --border: #ddd;
    --accent: #F7D74B;
    --success: #1a7a44;
    --danger:  #c0392b;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--fg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    font-size: 16px;
    line-height: 1.55;
}

header {
    width: 100%;
    max-width: 480px;
    display: flex;
    align-items: center;
    padding: 1.25rem 1.25rem 0.5rem;
}

main {
    width: 100%;
    max-width: 480px;
    display: flex;
    flex-direction: column;
    padding: 0 1rem 1rem 1rem;
}

/* ── Global Buttons ────────────────────────────────────── */
.primary-btn {
    width: 100%;
    padding: 0.65rem 1rem;
    font-size: 1rem;
    font-weight: 500;
    background: var(--accent);
    color: var(--fg);
    border: none;
    border-radius: 999px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: transform 120ms ease, opacity 120ms ease;
    text-align: center;
    text-decoration: none;
    display: block;
}
.primary-btn:disabled { 
    opacity: 0.4; 
    cursor: default; 
    box-shadow: none; 
}
.primary-btn:not(:disabled):active { 
    transform: scale(0.98); 
    opacity: 0.85;
}