/* ===== 基础 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --bg: #f1f5f9;
    --card: #ffffff;
    --text: #0f172a;
    --muted: #64748b;
    --border: #e2e8f0;
    --danger: #dc2626;
    --success: #16a34a;
    --radius: 12px;
    --shadow: 0 1px 3px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.05);
}
html { font-size: 16px; }
body {
    font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
.container { width: 100%; max-width: 960px; margin: 0 auto; padding: 0 20px; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ===== 顶栏 ===== */
.topbar {
    background: var(--card);
    border-bottom: 1px solid var(--border);
    position: sticky; top: 0; z-index: 20;
}
.topbar-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { display: flex; align-items: center; gap: 8px; color: var(--text); font-weight: 700; }
.brand:hover { text-decoration: none; }
.brand-icon { font-size: 22px; }
.brand-name { font-size: 17px; }
.nav { display: flex; gap: 4px; }
.nav a {
    padding: 8px 14px;
    border-radius: 8px;
    color: var(--muted);
    font-size: 14px;
    transition: all .15s;
}
.nav a:hover { background: var(--bg); color: var(--text); text-decoration: none; }
.nav a.active { background: var(--primary); color: #fff; }

/* ===== 主体 ===== */
.main { flex: 1; padding: 32px 20px 48px; }

/* ===== 卡片 ===== */
.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 28px;
    margin-bottom: 20px;
}
.card h1 { font-size: 22px; margin-bottom: 6px; }
.card .sub { color: var(--muted); font-size: 14px; margin-bottom: 22px; }
.card h2 { font-size: 17px; margin: 18px 0 10px; }

/* ===== 表单 ===== */
.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 6px; }
.form-group .hint { font-size: 12px; color: var(--muted); margin-top: 4px; }
input[type=text], input[type=password], input[type=number], input[type=color],
select, textarea {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    font-family: inherit;
    background: #fff;
    color: var(--text);
    transition: border-color .15s, box-shadow .15s;
}
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37,99,235,.12);
}
input[type=color] { width: 56px; height: 40px; padding: 3px; cursor: pointer; }
input[type=file] {
    display: block;
    width: 100%;
    padding: 12px;
    border: 2px dashed var(--border);
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    background: #f8fafc;
    transition: border-color .15s;
}
input[type=file]:hover { border-color: var(--primary); }

/* 上传框 */
.dropzone { position: relative; }
.dropzone input[type=file] { padding: 34px 16px; text-align: center; }
.dropzone .dz-tip { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 6px; pointer-events: none; color: var(--muted); font-size: 14px; }
.dropzone .dz-tip .dz-icon { font-size: 30px; }
.dropzone.has-file .dz-tip { display: none; }
.file-meta { display: none; margin-top: 10px; font-size: 13px; color: var(--muted); background: #f8fafc; border: 1px solid var(--border); border-radius: 8px; padding: 10px 12px; }
.file-meta.show { display: block; }
.file-meta .fm-name { font-weight: 600; color: var(--text); word-break: break-all; }

/* 按钮 */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 6px;
    padding: 11px 22px;
    border: none; border-radius: 8px;
    font-size: 15px; font-weight: 600;
    cursor: pointer;
    transition: all .15s;
    background: var(--primary); color: #fff;
}
.btn:hover { background: var(--primary-dark); }
.btn:disabled { opacity: .55; cursor: not-allowed; }
.btn-block { width: 100%; }
.btn-secondary { background: #e2e8f0; color: var(--text); }
.btn-secondary:hover { background: #cbd5e1; }
.btn-success { background: var(--success); }
.btn-success:hover { background: #15803d; }

/* ===== 提示消息 ===== */
.flash {
    padding: 12px 16px;
    border-radius: 8px;
    margin-bottom: 18px;
    font-size: 14px;
    border: 1px solid;
}
.flash-error { background: #fef2f2; border-color: #fecaca; color: var(--danger); }
.flash-success { background: #f0fdf4; border-color: #bbf7d0; color: var(--success); }
.flash-info { background: #eff6ff; border-color: #bfdbfe; color: var(--primary-dark); }

/* ===== 结果框 ===== */
.result-box {
    margin-top: 20px;
    padding: 18px;
    border-radius: 10px;
    background: #f8fafc;
    border: 1px solid var(--border);
}
.result-box .result-file { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.result-box .result-name { font-weight: 600; word-break: break-all; }
.download-btn { flex-shrink: 0; }

/* ===== 进度条 ===== */
.progress-wrap { display: none; margin-top: 18px; }
.progress-wrap.show { display: block; }
.progress-track { height: 8px; background: var(--border); border-radius: 99px; overflow: hidden; }
.progress-bar { height: 100%; width: 0; background: var(--primary); border-radius: 99px; transition: width .3s; }
.progress-text { font-size: 13px; color: var(--muted); margin-top: 6px; text-align: center; }

/* ===== 首页功能卡 ===== */
.home-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; margin-top: 22px; }
.feature-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px;
    box-shadow: var(--shadow);
    transition: transform .15s, box-shadow .15s;
}
.feature-card:hover { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(0,0,0,.1); }
.feature-card .fc-icon { font-size: 30px; margin-bottom: 10px; }
.feature-card h3 { font-size: 16px; margin-bottom: 6px; }
.feature-card p { font-size: 13px; color: var(--muted); margin-bottom: 14px; }
.feature-card .btn { font-size: 13px; padding: 8px 16px; }

/* ===== 工具提示 ===== */
.tips { font-size: 13px; color: var(--muted); background: #f8fafc; border: 1px solid var(--border); border-radius: 10px; padding: 14px 16px; margin-top: 20px; }
.tips ul { padding-left: 18px; }
.tips li { margin: 4px 0; }

/* ===== 调色滑块 ===== */
.range-group { margin-bottom: 14px; }
.range-group .rg-head { display: flex; justify-content: space-between; font-size: 14px; font-weight: 600; margin-bottom: 4px; }
.range-group .rg-val { color: var(--primary); font-weight: 700; }
input[type=range] { width: 100%; accent-color: var(--primary); }

/* ===== 单选组（水印位置） ===== */
.pos-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.pos-grid label {
    display: flex; align-items: center; justify-content: center;
    padding: 9px 4px; border: 1.5px solid var(--border); border-radius: 8px;
    font-size: 13px; cursor: pointer; transition: all .15s; background: #fff;
}
.pos-grid input { display: none; }
.pos-grid label:has(input:checked) { border-color: var(--primary); background: #eff6ff; color: var(--primary-dark); font-weight: 600; }

/* 字体预览 */
.font-preview {
    margin-top: 10px; padding: 12px 14px; border: 1px solid var(--border); border-radius: 8px;
    background: #fff; font-size: 18px; color: #334155;
}

/* 响应式 */
@media (max-width: 640px) {
    .topbar-inner { flex-direction: column; height: auto; padding: 10px 0; gap: 8px; }
    .nav { flex-wrap: wrap; justify-content: center; }
    .nav a { font-size: 13px; padding: 6px 10px; }
    .card { padding: 20px; }
}