/* ========== 全局重置 & 字体 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Roboto, Arial, sans-serif;
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 2rem 1.5rem;
    line-height: 1.5;
    background: linear-gradient(145deg, #f0f4fa, #e9f0f5); /* 默认渐变，会被JS随机覆盖 */
    background-attachment: fixed;
    transition: background 0.3s ease;
}

/* ========== 毛玻璃容器 ========== */
.glass-container {
    width: 100%;
    max-width: 950px;
    margin: 0 auto;
}

.glass-card {
    background: rgba(255, 255, 255, 0.68);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    border-radius: 36px;
    padding: 2.2rem 2.5rem;
    box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.08), 0 1px 3px rgba(0,0,0,0.02);
    border: 1px solid rgba(255, 255, 255, 0.6);
    margin-bottom: 1.8rem;
    transition: all 0.25s ease;
}

/* ========== 导航栏 ========== */
.nav-bar {
    display: flex;
    justify-content: center;
    gap: 1.2rem;
    margin-bottom: 2.2rem;
    background: rgba(255, 255, 255, 0.58);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 0.8rem 1.8rem;
    border-radius: 80px;
    border: 1px solid rgba(255, 255, 255, 0.8);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.02);
    flex-wrap: wrap;
}

.nav-btn {
    background: rgba(255,255,255,0.3);
    padding: 0.7rem 1.8rem;
    border-radius: 60px;
    font-size: 1.05rem;
    font-weight: 600;
    color: #1c1c1e;
    text-decoration: none;
    transition: 0.2s;
    border: 1px solid rgba(255,255,255,0.2);
    backdrop-filter: blur(4px);
}

.nav-btn.active {
    background: #007aff;
    color: white;
    border-color: rgba(255,255,255,0.5);
    box-shadow: 0 6px 12px rgba(0,122,255,0.25);
}

.nav-btn:hover:not(.active) {
    background: rgba(0,122,255,0.12);
    color: #007aff;
    border-color: rgba(0,122,255,0.3);
}

/* ========== 标题 ========== */
.glass-header {
    font-size: 2rem;
    font-weight: 600;
    letter-spacing: -0.5px;
    color: #1c1c1e;
    margin-bottom: 0.6rem;
    background: linear-gradient(130deg, #1c1c1e, #2a2a2e);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* ========== 按钮（007aff 主色） ========== */
button, .btn-like, .btn-delete, .btn-upload, .file-input-label {
    background: #007aff;
    border: none;
    border-radius: 50px;
    padding: 0.7rem 1.8rem;
    color: white;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: 0.2s;
    border: 1px solid rgba(255,255,255,0.2);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
}

button:hover, .btn-delete:hover, .btn-upload:hover, .file-input-label:hover {
    background: #005bbf;
    transform: scale(1.02);
    box-shadow: 0 9px 18px rgba(0,122,255,0.35);
}

.btn-delete, .btn-upload {
    padding: 0.9rem 2.2rem;
    font-size: 1.1rem;
}

/* ========== 文件列表 ========== */
.file-list {
    list-style: none;
    padding: 0;
    margin: 1.8rem 0 0.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.file-item {
    background: rgba(255,255,255,0.5);
    backdrop-filter: blur(5px);
    padding: 1rem 1.6rem;
    border-radius: 16px;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    border: 1px solid rgba(255,255,255,0.6);
    box-shadow: 0 2px 6px rgba(0,0,0,0.02);
    color: #1c1c1e;
    font-weight: 470;
}

.file-icon {
    margin-right: 1rem;
    font-size: 1.4rem;
}

.empty-message {
    padding: 2.5rem;
    text-align: center;
    color: #5e5e5e;
    font-style: italic;
    background: rgba(255,255,255,0.3);
    border-radius: 24px;
    backdrop-filter: blur(4px);
}

/* ========== 欢迎页专用 ========== */
.welcome-card {
    text-align: center;
    padding: 2.5rem 2rem;
}
.welcome-card h1 {
    font-size: 2.8rem;
    font-weight: 500;
    margin-bottom: 1.2rem;
    letter-spacing: -0.5px;
    background: linear-gradient(145deg, #1c1c1e, #3a3a3c);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.welcome-card p {
    font-size: 1.4rem;
    color: #1c1c1e;
    opacity: 0.8;
    font-weight: 400;
    margin: 1rem 0;
}
.redirect-note {
    margin-top: 2rem;
    font-size: 1.1rem;
    color: #007aff;
    font-weight: 500;
}

/* ========== 编辑页复选框 ========== */
.checkbox-item {
    display: flex;
    align-items: center;
    gap: 1rem;
}
.file-checkbox {
    width: 1.4rem;
    height: 1.4rem;
    border-radius: 8px;
    border: 2px solid #007aff;
    accent-color: #007aff;
    cursor: pointer;
}
.delete-area {
    margin-top: 2.2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid rgba(0,122,255,0.2);
    padding-top: 1.8rem;
    flex-wrap: wrap;
}
.select-actions {
    display: flex;
    gap: 1.2rem;
    color: #007aff;
    font-weight: 500;
}
.select-actions span {
    cursor: pointer;
    padding: 0.4rem 0.8rem;
    background: rgba(0,122,255,0.08);
    border-radius: 30px;
    font-size: 0.95rem;
}

/* ========== 上传页 ========== */
.upload-area {
    background: rgba(255,255,255,0.4);
    backdrop-filter: blur(8px);
    border-radius: 28px;
    padding: 2.5rem 2rem;
    margin-top: 1.2rem;
    border: 2px dashed rgba(0,122,255,0.4);
    transition: 0.2s;
    text-align: center;
}
.upload-area:hover {
    border-color: #007aff;
    background: rgba(255,255,255,0.6);
}
.file-input-label {
    margin-bottom: 1.2rem;
    cursor: pointer;
}
#file-input {
    display: none;
}
.selected-file-name {
    margin-top: 1rem;
    font-size: 1.1rem;
    color: #1c1c1e;
    background: rgba(255,255,255,0.5);
    padding: 0.7rem 1.4rem;
    border-radius: 40px;
    display: inline-block;
    backdrop-filter: blur(4px);
}
.btn-upload {
    margin-top: 1.8rem;
    width: 100%;
    max-width: 280px;
}
.btn-upload:disabled {
    background: #a0c4ff;
    box-shadow: none;
    transform: none;
    cursor: not-allowed;
}

/* ========== 徽章 & 标注 ========== */
.badge {
    background: #007aff;
    color: white;
    padding: 0.3rem 1rem;
    border-radius: 40px;
    font-size: 0.9rem;
    font-weight: 500;
}
.page-title {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

/* ========== 响应式 ========== */
@media (max-width: 600px) {
    .glass-card {
        padding: 1.8rem 1.5rem;
        border-radius: 28px;
    }
    .nav-btn {
        padding: 0.5rem 1.2rem;
        font-size: 0.95rem;
    }
    .glass-header {
        font-size: 1.8rem;
    }
    .welcome-card h1 {
        font-size: 2.2rem;
    }
}

/* ========== 滚动条 ========== */
::-webkit-scrollbar {
    width: 8px;
}
::-webkit-scrollbar-track {
    background: rgba(0,0,0,0.02);
    border-radius: 20px;
}
::-webkit-scrollbar-thumb {
    background: rgba(0,122,255,0.4);
    border-radius: 20px;
}