/* 日期天数计算器 */
:root {
    --dc-bg: #0f172a;
    --dc-card: #1e293b;
    --dc-card-hi: #2a3a52;
    --dc-border: #334155;
    --dc-text: #e2e8f0;
    --dc-text-mute: #94a3b8;
    --dc-accent: #818cf8;
    --dc-accent-solid: #6366f1;
    --dc-accent-bg: rgba(99, 102, 241, 0.15);
    --dc-success: #34d399;
    --dc-warning: #fbbf24;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    background: var(--dc-bg);
    color: var(--dc-text);
    min-height: 100vh;
    line-height: 1.55;
}

.dc-fullscreen {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.dc-header {
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--dc-border);
    height: 56px;
    padding: 0 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    position: sticky;
    top: 0;
    z-index: 100;
}
.dc-back {
    color: var(--dc-text-mute);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    transition: color .15s;
}
.dc-back:hover { color: var(--dc-text); }
.dc-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--dc-text);
}
.dc-spacer { flex: 1; }

.dc-main {
    flex: 1;
    padding: 24px 16px 60px;
    max-width: 720px;
    width: 100%;
    margin: 0 auto;
}

.dc-card {
    background: var(--dc-card);
    border: 1px solid var(--dc-border);
    border-radius: 16px;
    padding: 24px;
}

/* Tabs */
.dc-tabs {
    display: flex;
    gap: 6px;
    background: var(--dc-bg);
    border: 1px solid var(--dc-border);
    border-radius: 10px;
    padding: 4px;
    margin-bottom: 24px;
}
.dc-tab {
    flex: 1;
    background: transparent;
    color: var(--dc-text-mute);
    border: none;
    padding: 9px 8px;
    border-radius: 7px;
    cursor: pointer;
    font-size: 14px;
    font-family: inherit;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    transition: all .15s;
}
.dc-tab:hover { color: var(--dc-text); }
.dc-tab.active {
    background: var(--dc-accent-bg);
    color: var(--dc-accent);
    font-weight: 500;
}
.dc-tab i { font-size: 16px; }

.dc-pane.hidden { display: none; }

.dc-row {
    margin-bottom: 16px;
}
.dc-label {
    display: block;
    font-size: 13px;
    color: var(--dc-text-mute);
    margin-bottom: 6px;
}
.dc-input {
    width: 100%;
    padding: 11px 14px;
    border-radius: 8px;
    background: var(--dc-bg);
    border: 1px solid var(--dc-border);
    color: var(--dc-text);
    font-size: 15px;
    font-family: inherit;
    outline: none;
    transition: border-color .15s, box-shadow .15s;
}
.dc-input:focus {
    border-color: var(--dc-accent-solid);
    box-shadow: 0 0 0 3px var(--dc-accent-bg);
}
/* 让 PC 端 <input type="date"> 的内嵌日历图标变灰白色（暗色主题适配） */
.dc-input[type="date"] {
    color-scheme: dark;
}
.dc-input[type="date"]::-webkit-calendar-picker-indicator {
    cursor: pointer;
    opacity: 0.7;
}
.dc-input[type="date"]::-webkit-calendar-picker-indicator:hover {
    opacity: 1;
}
.dc-select {
    cursor: pointer;
    -webkit-appearance: none;
    appearance: none;
    background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='%2394a3b8'><path d='M8 11L3 6h10z'/></svg>");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 36px;
}
.dc-hint {
    font-size: 12px;
    color: var(--dc-text-mute);
    margin-top: 4px;
}

.dc-checkbox {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 14px;
    color: var(--dc-text-mute);
    user-select: none;
}
.dc-checkbox-box {
    display: inline-flex;
    align-items: center;
    flex-shrink: 0;
}
.dc-checkbox-box input {
    margin: 0;
    width: 16px;
    height: 16px;
    cursor: pointer;
}
.dc-checkbox-text {
    white-space: nowrap;
}
.dc-checkbox:hover { color: var(--dc-text); }

.dc-add-inline {
    display: flex;
    gap: 8px;
    align-items: center;
}
.dc-add-inline .dc-select { flex: 0 0 140px; }
.dc-add-inline .dc-input[type=number] { flex: 1; }
.dc-add-suffix { color: var(--dc-text-mute); font-size: 14px; }

/* Result */
.dc-result {
    margin-top: 20px;
    padding: 18px 20px;
    background: linear-gradient(180deg, var(--dc-card-hi), var(--dc-card));
    border: 1px solid var(--dc-border);
    border-radius: 12px;
    min-height: 80px;
}
.dc-result-empty {
    color: var(--dc-text-mute);
    font-size: 14px;
    text-align: center;
    padding: 12px 0;
}
.dc-result-main {
    font-size: 28px;
    font-weight: 600;
    color: var(--dc-accent);
    line-height: 1.25;
    margin-bottom: 10px;
    word-break: break-all;
}
.dc-result-main em {
    font-style: normal;
    color: var(--dc-text);
    font-size: 22px;
    margin: 0 4px;
}
.dc-result-main .dc-num {
    font-variant-numeric: tabular-nums;
}
.dc-result-sub {
    font-size: 14px;
    color: var(--dc-text-mute);
    line-height: 1.7;
}
.dc-result-sub b {
    color: var(--dc-text);
    font-weight: 500;
}
.dc-result-warning {
    color: var(--dc-warning);
    font-size: 14px;
    text-align: center;
    padding: 12px 0;
}

.dc-foot {
    margin-top: 18px;
    color: var(--dc-text-mute);
    font-size: 12px;
    text-align: center;
}

/* SEO description */
.dc-seo {
    margin-top: 36px;
    padding: 20px 24px;
    background: var(--dc-card);
    border: 1px solid var(--dc-border);
    border-radius: 12px;
    color: var(--dc-text-mute);
    font-size: 14px;
}
.dc-seo h2 {
    color: var(--dc-text);
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 12px;
}
.dc-seo p {
    margin-bottom: 10px;
}
.dc-seo p:last-child { margin-bottom: 0; }
.dc-seo b {
    color: var(--dc-text);
    font-weight: 500;
}
.dc-seo i {
    color: var(--dc-accent);
    font-style: normal;
}

@media (max-width: 540px) {
    .dc-tab { font-size: 13px; padding: 8px 4px; }
    .dc-tab i { font-size: 14px; }
    .dc-card { padding: 18px; }
    .dc-result-main { font-size: 22px; }
    .dc-result-main em { font-size: 18px; }
    .dc-add-inline .dc-select { flex: 0 0 110px; font-size: 13px; }
    .dc-main { padding: 16px 12px 60px; }
}