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

:root {
    --color-bg: #f5f5f7;
    --color-surface: #ffffff;
    --color-primary: #e85d3a;
    --color-primary-hover: #d44d2a;
    --color-text: #1d1d1f;
    --color-text-secondary: #6e6e73;
    --color-border: #d2d2d7;
    --color-header-bg: rgba(255, 255, 255, 0.85);
    --sidebar-width: 320px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

a {
    color: var(--color-primary);
    text-decoration: none;
}

a:hover {
    color: var(--color-primary-hover);
}

/* ── Header ── */

.header {
    flex-shrink: 0;
    background: var(--color-header-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 48px;
    padding: 0 20px;
}

.logo {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--color-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.nav {
    display: flex;
    align-items: center;
    gap: 20px;
}

.nav-link {
    font-size: 0.8125rem;
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-text);
}

/* ── App Layout ── */

.app-layout {
    flex: 1;
    display: flex;
    overflow: hidden;
}

/* ── Sidebar ── */

.sidebar {
    width: var(--sidebar-width);
    flex-shrink: 0;
    overflow-y: auto;
    border-right: 1px solid var(--color-border);
    background: var(--color-surface);
}

.sidebar-empty {
    padding: 24px 16px;
    text-align: center;
    font-size: 0.8125rem;
    color: var(--color-text-secondary);
}

.sidebar-empty p {
    margin-bottom: 8px;
}

.sidebar-item {
    padding: 12px 16px;
    cursor: pointer;
    border-bottom: 1px solid var(--color-border);
    transition: background 0.15s;
}

.sidebar-item:hover {
    background: var(--color-bg);
}

.sidebar-item.active {
    background: var(--color-bg);
    border-left: 3px solid var(--color-primary);
    padding-left: 13px;
}

.sidebar-item-title {
    font-size: 0.8125rem;
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: 4px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.sidebar-item-meta {
    font-size: 0.6875rem;
    color: var(--color-text-secondary);
    display: flex;
    align-items: center;
    gap: 6px;
}

.sidebar-item-feed {
    color: var(--color-primary);
    font-weight: 600;
}

/* ── Content ── */

.content {
    flex: 1;
    overflow-y: auto;
    background: var(--color-surface);
}

.content-empty {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--color-text-secondary);
}

.content-empty h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 8px;
}

.content-empty p {
    font-size: 0.875rem;
}

/* ── Article Detail ── */

.article-detail {
    padding: 32px 40px 80px;
}

.article-title {
    font-size: 1.75rem;
    font-weight: 700;
    line-height: 1.3;
    letter-spacing: -0.02em;
    margin-bottom: 12px;
}

.article-meta {
    font-size: 0.8125rem;
    color: var(--color-text-secondary);
    display: flex;
    align-items: center;
    gap: 12px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--color-border);
    margin-bottom: 24px;
}

.article-feed {
    font-weight: 600;
    color: var(--color-primary);
}

.article-link {
    margin-left: auto;
}

.article-body {
    font-size: 1rem;
    line-height: 1.75;
    color: var(--color-text);
}

.article-body p {
    margin-bottom: 1em;
}

.article-body img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 1em 0;
}

.article-body a {
    color: var(--color-primary);
    text-decoration: underline;
}

.article-body blockquote {
    border-left: 3px solid var(--color-border);
    padding-left: 16px;
    margin: 1em 0;
    color: var(--color-text-secondary);
}

.article-body pre,
.article-body code {
    font-family: "SF Mono", Menlo, monospace;
    font-size: 0.875rem;
    background: var(--color-bg);
    border-radius: 4px;
    padding: 2px 6px;
}

.article-body pre {
    padding: 16px;
    overflow-x: auto;
    margin: 1em 0;
}

.article-body pre code {
    background: none;
    padding: 0;
}

.article-body ul,
.article-body ol {
    margin: 1em 0;
    padding-left: 24px;
}

.article-body h1,
.article-body h2,
.article-body h3,
.article-body h4 {
    margin-top: 1.5em;
    margin-bottom: 0.5em;
    font-weight: 600;
}

/* ── Centered pages (subscribe / settings) ── */

.page {
    max-width: 720px;
    margin: 0 auto;
    padding: 0 20px;
}

.page-header {
    padding: 32px 0 24px;
}

.page-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 4px;
}

.page-header p {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

.feed-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding-bottom: 48px;
}

.feed-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 10px;
    padding: 20px 24px;
}

.subscribe-card {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.subscribe-info {
    flex: 1;
    min-width: 0;
}

.subscribe-info h3 {
    font-size: 0.9375rem;
    font-weight: 600;
    margin-bottom: 2px;
}

.subscribe-info p {
    font-size: 0.8125rem;
    color: var(--color-text-secondary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.subscribe-btn {
    flex-shrink: 0;
    border: 1px solid var(--color-primary);
    border-radius: 20px;
    padding: 5px 16px;
    font-size: 0.8125rem;
    font-weight: 600;
    cursor: pointer;
    background: var(--color-surface);
    color: var(--color-primary);
    transition: all 0.2s;
    white-space: nowrap;
}

.subscribe-btn:hover {
    background: var(--color-primary);
    color: #fff;
}

.subscribe-btn.subscribed {
    background: var(--color-primary);
    color: #fff;
}

.subscribe-btn.subscribed:hover {
    background: var(--color-primary-hover);
    border-color: var(--color-primary-hover);
}

/* ── Form (settings) ── */

.form-label {
    display: block;
    font-size: 0.9375rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.form-hint {
    font-size: 0.8125rem;
    color: var(--color-text-secondary);
    margin-bottom: 12px;
}

.form-textarea {
    width: 100%;
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: 10px 12px;
    font-family: inherit;
    font-size: 0.875rem;
    line-height: 1.5;
    resize: vertical;
    outline: none;
    transition: border-color 0.2s;
}

.form-textarea:focus {
    border-color: var(--color-primary);
}

.form-btn {
    margin-top: 12px;
    border: none;
    border-radius: 20px;
    padding: 7px 24px;
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    background: var(--color-primary);
    color: #fff;
    transition: background 0.2s;
}

.form-btn:hover {
    background: var(--color-primary-hover);
}

.form-toast {
    margin-left: 12px;
    font-size: 0.8125rem;
    color: var(--color-primary);
    opacity: 0;
    transition: opacity 0.3s;
}

.form-toast.show {
    opacity: 1;
}

/* ── About ── */

.about-card p {
    font-size: 0.9375rem;
    line-height: 1.8;
    margin-bottom: 1em;
}

.about-sign {
    margin-top: 24px;
    padding-top: 16px;
    border-top: 1px solid var(--color-border);
    color: var(--color-primary);
    font-weight: 600;
}

/* ── Mobile ── */

.back-btn {
    display: none;
}

@media (max-width: 768px) {
    .header-inner {
        padding: 0 12px;
        height: 44px;
    }

    .logo {
        font-size: 1rem;
    }

    .nav {
        gap: 12px;
    }

    .nav-link {
        font-size: 0.75rem;
    }

    .app-layout {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        flex: 1;
    }

    .sidebar.mobile-hidden {
        display: none;
    }

    .content {
        display: none;
        flex: 1;
    }

    .content.mobile-visible {
        display: block;
    }

    .content-empty h2 {
        font-size: 1.25rem;
    }

    .back-btn {
        display: block;
        width: 100%;
        border: none;
        border-bottom: 1px solid var(--color-border);
        background: var(--color-bg);
        padding: 10px 16px;
        font-size: 0.875rem;
        font-family: inherit;
        color: var(--color-primary);
        cursor: pointer;
        text-align: left;
        font-weight: 600;
    }

    .back-btn:hover {
        background: var(--color-border);
    }

    .article-detail {
        padding: 20px 16px 60px;
    }

    .article-title {
        font-size: 1.375rem;
    }

    .article-meta {
        flex-wrap: wrap;
        gap: 6px;
    }

    .article-link {
        margin-left: 0;
    }

    .sidebar-item {
        padding: 10px 12px;
    }

    .sidebar-item.active {
        padding-left: 9px;
    }

    .page {
        padding: 0 12px;
    }

    .page-header {
        padding: 20px 0 16px;
    }

    .page-header h1 {
        font-size: 1.25rem;
    }

    .subscribe-card {
        padding: 14px 16px;
    }

    .about-card p {
        font-size: 0.875rem;
    }
}