/* ============================================================
   摇滚虎鲸官网 — 高级视觉设计系统
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;600;700&display=swap');

:root {
    --color-bg: #f4f6fb;
    --color-bg-alt: #eef2f9;
    --color-surface: #ffffff;
    --color-text: #0f172a;
    --color-text-secondary: #64748b;
    --color-text-muted: #94a3b8;
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-accent: #06b6d4;
    --color-accent-warm: #f59e0b;
    --color-navy: #0b1220;
    --color-navy-mid: #152238;
    --color-navy-soft: #1e3a5f;
    --gradient-brand: linear-gradient(135deg, #0b1220 0%, #152238 45%, #1e3a5f 100%);
    --gradient-hero: linear-gradient(145deg, #060d18 0%, #0f1f3d 40%, #1a3a6e 75%, #0e7490 100%);
    --gradient-cta: linear-gradient(135deg, #0b1220 0%, #1e40af 50%, #0891b2 100%);
    --gradient-card-shine: linear-gradient(135deg, rgba(37, 99, 235, 0.08) 0%, rgba(6, 182, 212, 0.04) 100%);
    --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.04);
    --shadow-sm: 0 4px 12px rgba(15, 23, 42, 0.06);
    --shadow-md: 0 8px 24px rgba(15, 23, 42, 0.08);
    --shadow-lg: 0 16px 48px rgba(15, 23, 42, 0.12);
    --shadow-glow: 0 0 40px rgba(37, 99, 235, 0.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;
    --header-height: 72px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
    --container: 1200px;
}

/* =================== Reset & Base =================== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font);
    color: var(--color-text);
    line-height: 1.7;
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    width: 100%;
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
}

.content-wrapper {
    display: flex;
    flex-wrap: wrap;
    gap: 40px;
}

.main-content {
    flex: 1;
    min-width: 0;
}

.sidebar {
    width: 100%;
    max-width: 340px;
}

@media (max-width: 992px) {
    .content-wrapper { flex-direction: column; }
    .sidebar { max-width: 100%; }
}

/* =================== Buttons =================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 0.95rem;
    text-align: center;
    cursor: pointer;
    border: none;
    transition: all var(--transition);
    letter-spacing: 0.02em;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: #fff;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(37, 99, 235, 0.45);
    color: #fff;
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.12);
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.35);
    backdrop-filter: blur(8px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.2);
    color: #fff;
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.5);
    color: #fff;
}

.btn-outline:hover {
    background: rgba(255, 255, 255, 0.1);
    color: #fff;
}

.btn-block { display: block; width: 100%; }
.btn-sm { padding: 10px 20px; font-size: 0.875rem; }

/* =================== Forms =================== */
.form-group { margin-bottom: 16px; }

input, select, textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid #e2e8f0;
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 0.95rem;
    transition: border-color var(--transition), box-shadow var(--transition);
    background: var(--color-surface);
}

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

textarea { min-height: 120px; resize: vertical; }

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

.form-hint {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-top: 8px;
}

.form-row {
    display: flex;
    gap: 16px;
}

.form-row .form-group { flex: 1; }

@media (max-width: 576px) {
    .form-row { flex-direction: column; gap: 0; }
}

/* =================== Header (legacy + site-header) =================== */
header,
.site-header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(11, 18, 32, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    transition: background var(--transition), box-shadow var(--transition);
}

header.scrolled,
.site-header.scrolled {
    background: rgba(11, 18, 32, 0.95);
    box-shadow: var(--shadow-md);
}

.header-content,
.site-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    min-height: var(--header-height);
    padding: 12px 24px;
}

.logo {
    font-size: 1.15rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 10px;
    color: #fff;
    letter-spacing: -0.02em;
}

.logo-icon img,
.logo img {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    object-fit: contain;
}

nav ul,
.main-nav ul {
    display: flex;
    align-items: center;
    gap: 4px;
}

nav ul li,
.main-nav li {
    margin: 0;
}

nav ul li a,
.main-nav a {
    color: rgba(255, 255, 255, 0.75);
    font-weight: 500;
    font-size: 0.9rem;
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    transition: all var(--transition);
    text-decoration: none;
    position: relative;
}

nav ul li a:hover,
.main-nav a:hover {
    color: #fff;
    background: rgba(255, 255, 255, 0.08);
    text-decoration: none;
}

nav ul li a.active,
.main-nav a.active {
    color: #fff;
    background: rgba(37, 99, 235, 0.25);
}

.main-nav a::after {
    display: none;
}

.header-cta {
    display: flex;
    gap: 12px;
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px;
}

.mobile-menu-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: #fff;
    margin: 5px 0;
    transition: all var(--transition);
    border-radius: 2px;
}

@media (max-width: 992px) {
    .main-nav, .header-cta { display: none; }

    .mobile-menu-toggle { display: block; }

    nav ul {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        background: var(--color-navy);
        padding: 16px;
        border-bottom: 1px solid rgba(255, 255, 255, 0.08);
        box-shadow: var(--shadow-lg);
    }

    nav.nav-open ul,
    .main-nav.active {
        display: flex;
    }

    .main-nav.active {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--color-navy);
        padding: 20px;
        box-shadow: var(--shadow-lg);
    }

    .main-nav.active ul {
        flex-direction: column;
        align-items: stretch;
    }

    .header-content {
        flex-wrap: wrap;
        position: relative;
    }
}

/* =================== Hero =================== */
.hero {
    position: relative;
    min-height: 88vh;
    display: flex;
    align-items: center;
    overflow: hidden;
    background: var(--gradient-hero);
    padding: 100px 0 80px;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 50% at 20% 40%, rgba(37, 99, 235, 0.25) 0%, transparent 50%),
        radial-gradient(ellipse 60% 40% at 80% 60%, rgba(6, 182, 212, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 50% 100%, rgba(15, 23, 42, 0.8) 0%, transparent 60%);
    pointer-events: none;
}

.hero::after {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 60px 60px;
    mask-image: radial-gradient(ellipse 70% 60% at 50% 50%, black 20%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
    color: #fff;
    max-width: 720px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 14px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 500;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 24px;
    backdrop-filter: blur(8px);
}

.hero-badge::before {
    content: '';
    width: 6px;
    height: 6px;
    background: var(--color-accent);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--color-accent);
}

.hero h1 {
    font-size: clamp(2rem, 5vw, 3.25rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
    letter-spacing: -0.03em;
}

.hero h1 .highlight {
    background: linear-gradient(135deg, #60a5fa 0%, #22d3ee 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: rgba(255, 255, 255, 0.75);
    margin-bottom: 36px;
    max-width: 560px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
}

/* =================== Sections =================== */
section {
    padding: 96px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 64px;
}

.section-title .label {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--color-primary);
    margin-bottom: 12px;
}

.section-title h2 {
    font-size: clamp(1.75rem, 3vw, 2.25rem);
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}

.section-title p {
    font-size: 1.05rem;
    color: var(--color-text-secondary);
    max-width: 640px;
    margin: 0 auto;
    line-height: 1.8;
}

/* =================== Feature Cards =================== */
#features {
    background: var(--color-surface);
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.feature-card {
    position: relative;
    background: var(--color-surface);
    border: 1px solid #e8edf5;
    border-radius: var(--radius-lg);
    padding: 32px;
    transition: all var(--transition);
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    opacity: 0;
    transition: opacity var(--transition);
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.feature-card:hover::before {
    opacity: 1;
}

.feature-icon {
    width: 52px;
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-primary);
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1) 0%, rgba(6, 182, 212, 0.08) 100%);
    border: 1px solid rgba(37, 99, 235, 0.12);
    border-radius: var(--radius-md);
    margin-bottom: 20px;
    transition: all var(--transition);
}

.feature-icon svg {
    width: 26px;
    height: 26px;
    fill: none;
    stroke: currentColor;
}

.feature-card:hover .feature-icon {
    color: #fff;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    border-color: transparent;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
}

.feature-card h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--color-text);
}

.feature-card p {
    font-size: 0.95rem;
    color: var(--color-text-secondary);
    line-height: 1.75;
}

/* scroll reveal */
.reveal {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* =================== About =================== */
.about {
    background: var(--color-bg-alt);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 56px;
    align-items: center;
}

.about-image {
    position: relative;
}

.about-image::before {
    content: '';
    position: absolute;
    inset: -12px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    border-radius: var(--radius-xl);
    opacity: 0.12;
    z-index: 0;
}

.about-image img {
    position: relative;
    z-index: 1;
    width: 100%;
    height: auto;
    aspect-ratio: 4 / 3;
    object-fit: cover;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.about-text h3 {
    font-size: clamp(1.5rem, 2.5vw, 2rem);
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--color-text);
    letter-spacing: -0.02em;
}

.about-text p {
    margin-bottom: 16px;
    color: var(--color-text-secondary);
    line-height: 1.85;
}

.stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-top: 64px;
}

.stat-item {
    text-align: center;
    padding: 32px 20px;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid #e8edf5;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
}

.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: rgba(37, 99, 235, 0.2);
}

.stat-item h4 {
    font-size: 2.25rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
    line-height: 1.2;
}

.stat-item p {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    font-weight: 500;
}

/* =================== CTA =================== */
.cta {
    position: relative;
    background: var(--gradient-cta);
    color: #fff;
    text-align: center;
    padding: 100px 0;
    overflow: hidden;
}

.cta::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 50% 80% at 50% 120%, rgba(6, 182, 212, 0.2) 0%, transparent 60%);
}

.cta .container {
    position: relative;
    z-index: 1;
}

.cta h3 {
    font-size: clamp(1.5rem, 3vw, 2.25rem);
    font-weight: 700;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}

.cta p {
    font-size: 1.05rem;
    color: rgba(255, 255, 255, 0.8);
    max-width: 600px;
    margin: 0 auto 32px;
    line-height: 1.8;
}

/* =================== Footer =================== */
footer,
.site-footer {
    background: var(--color-navy);
    color: rgba(255, 255, 255, 0.65);
    padding: 72px 0 28px;
}

.footer-content,
.footer-top {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 48px;
}

.footer-column h3,
.footer-col h4 {
    font-size: 1rem;
    font-weight: 600;
    color: #fff;
    margin-bottom: 20px;
    position: relative;
    padding-bottom: 12px;
}

.footer-column h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 32px;
    height: 2px;
    background: linear-gradient(90deg, var(--color-primary-light), var(--color-accent));
    border-radius: 2px;
}

.footer-column ul li,
.footer-links li {
    margin-bottom: 10px;
}

.footer-column ul li a,
.footer-links a {
    color: rgba(255, 255, 255, 0.55);
    font-size: 0.9rem;
    transition: all var(--transition);
}

.footer-column ul li a:hover,
.footer-links a:hover {
    color: #fff;
    padding-left: 4px;
}

.footer-column ul li {
    font-size: 0.9rem;
    line-height: 1.7;
}

.copyright,
.footer-bottom {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.4);
}

.copyright a,
.copyright p {
    color: inherit;
}

/* =================== Page Banner (inner pages) =================== */
.page-header,
.page-banner {
    position: relative;
    background: var(--gradient-hero);
    color: #fff;
    padding: 80px 0 72px;
    text-align: center;
    overflow: hidden;
}

.page-header::before,
.page-banner::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 60% 50% at 30% 50%, rgba(37, 99, 235, 0.2) 0%, transparent 50%),
        radial-gradient(ellipse 50% 40% at 70% 60%, rgba(6, 182, 212, 0.12) 0%, transparent 50%);
}

.page-header h1,
.page-banner h1,
.banner-content h1 {
    position: relative;
    font-size: clamp(1.75rem, 4vw, 2.75rem);
    font-weight: 700;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

.page-header p,
.page-banner p,
.banner-content p {
    position: relative;
    font-size: 1.05rem;
    max-width: 640px;
    margin: 0 auto;
    color: rgba(255, 255, 255, 0.75);
    line-height: 1.8;
}

.page-header-content {
    position: relative;
    z-index: 1;
}

/* =================== Filter / Category Buttons =================== */
.platform-categories,
.case-filter,
.filter-buttons {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 48px;
}

.category-btn,
.filter-btn {
    padding: 10px 22px;
    background: var(--color-surface);
    border: 1px solid #e2e8f0;
    border-radius: var(--radius-full);
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    font-family: var(--font);
    color: var(--color-text-secondary);
    transition: all var(--transition);
}

.category-btn:hover,
.filter-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background: rgba(37, 99, 235, 0.04);
}

.category-btn.active,
.filter-btn.active {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: #fff;
    border-color: transparent;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.category-btn.active:hover,
.filter-btn.active:hover {
    color: #fff;
}

/* =================== Cards (generic) =================== */
.feature-detail,
.case-card,
.blog-card,
.whitepaper-card {
    background: var(--color-surface);
    border: 1px solid #e8edf5;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
}

.feature-detail:hover,
.case-card:hover,
.blog-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.feature-content h3,
.showcase-content h3 {
    color: var(--color-text);
}

.feature-content p,
.showcase-content p {
    color: var(--color-text-secondary);
}

.feature-content .feature-benefits h4 {
    color: var(--color-primary);
}

/* =================== Sidebar Widgets =================== */
.sidebar-widget {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid #e8edf5;
    box-shadow: var(--shadow-sm);
    padding: 24px;
    margin-bottom: 24px;
}

.widget-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid #f1f5f9;
    color: var(--color-text);
}

.cta-widget {
    background: var(--gradient-brand);
    color: #fff;
    border: none;
}

.cta-widget .widget-title {
    border-color: rgba(255, 255, 255, 0.1);
    color: #fff;
}

/* =================== Newsletter =================== */
.newsletter-section {
    padding: 80px 0;
    background: var(--color-bg-alt);
}

.newsletter-box {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    border: 1px solid #e8edf5;
    box-shadow: var(--shadow-md);
    padding: 48px;
    display: flex;
    align-items: center;
    gap: 40px;
}

.newsletter-content h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
}

.newsletter-form form {
    display: flex;
    align-items: stretch;
    gap: 0;
    max-width: 480px;
}

.newsletter-form input {
    flex: 1;
    min-width: 0;
    margin-bottom: 0;
    border-radius: var(--radius-full) 0 0 var(--radius-full);
    border: 1px solid #e2e8f0;
    border-right: none;
    padding: 14px 20px;
}

.newsletter-form input:focus {
    border-color: var(--color-primary);
    box-shadow: none;
}

.newsletter-form button {
    flex-shrink: 0;
    width: auto;
    padding: 14px 28px;
    border-radius: 0 var(--radius-full) var(--radius-full) 0;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: #fff;
    border: none;
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
    transition: all var(--transition);
}

.newsletter-form button:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 18px rgba(37, 99, 235, 0.45);
    color: #fff;
}

/* 侧边栏订阅（纵向） */
.subscribe-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.subscribe-form input {
    width: 100%;
    margin-bottom: 0;
    padding: 12px 16px;
    border: 1px solid #e2e8f0;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    background: var(--color-surface);
}

.subscribe-form input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

.subscribe-form button {
    width: 100%;
    padding: 12px 16px;
    border: none;
    border-radius: var(--radius-sm);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: #fff;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
    transition: all var(--transition);
}

.subscribe-form button:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(37, 99, 235, 0.4);
    color: #fff;
}

/* 横幅区订阅（邮箱 + 按钮横排） */
.subscribe-section {
    background: var(--gradient-cta);
    color: #fff;
    padding: 80px 0;
    text-align: center;
}

.subscribe-content {
    max-width: 640px;
    margin: 0 auto;
}

.subscribe-content h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 700;
    margin-bottom: 16px;
}

.subscribe-content p {
    font-size: 1.05rem;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 32px;
    line-height: 1.8;
}

.subscribe-form--inline {
    display: flex;
    flex-direction: row;
    align-items: stretch;
    max-width: 480px;
    margin: 0 auto;
    gap: 0;
}

.subscribe-form--inline input {
    flex: 1;
    min-width: 0;
    padding: 14px 20px;
    border: none;
    border-radius: var(--radius-full) 0 0 var(--radius-full);
    font-size: 0.95rem;
    background: #fff;
    color: var(--color-text);
}

.subscribe-form--inline input::placeholder {
    color: var(--color-text-muted);
}

.subscribe-form--inline input:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.25);
}

.subscribe-form--inline button {
    flex-shrink: 0;
    width: auto;
    padding: 14px 28px;
    border: none;
    border-radius: 0 var(--radius-full) var(--radius-full) 0;
    background: linear-gradient(135deg, #1d4ed8 0%, #2563eb 100%);
    color: #fff;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: none;
    transition: background var(--transition), transform var(--transition);
}

.subscribe-form--inline button:hover {
    background: linear-gradient(135deg, #1e40af 0%, #1d4ed8 100%);
    transform: none;
    color: #fff;
}

.sidebar-widget .subscribe-form + p,
.sidebar-widget > p {
    margin-bottom: 16px;
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
}

@media (max-width: 576px) {
    .newsletter-form form,
    .subscribe-form--inline {
        flex-direction: column;
        gap: 12px;
    }

    .newsletter-form input,
    .subscribe-form--inline input {
        border-radius: var(--radius-full);
        border-right: 1px solid #e2e8f0;
    }

    .newsletter-form button,
    .subscribe-form--inline button {
        width: 100%;
        border-radius: var(--radius-full);
    }
}

@media (max-width: 768px) {
    .newsletter-box {
        flex-direction: column;
        text-align: center;
        padding: 32px;
    }

    .newsletter-form form {
        margin: 0 auto;
    }
}

/* =================== Floating UI =================== */
.back-to-top {
    position: fixed;
    bottom: 28px;
    right: 28px;
    width: 44px;
    height: 44px;
    background: var(--color-primary);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition);
    box-shadow: var(--shadow-md);
    z-index: 99;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--color-primary-dark);
    transform: translateY(-3px);
}

.reading-progress-container {
    position: fixed;
    top: 0;
    z-index: 1001;
    width: 100%;
    height: 3px;
    background: transparent;
}

.reading-progress-bar {
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    width: 0%;
}

/* =================== Responsive =================== */
@media (max-width: 768px) {
    section { padding: 64px 0; }

    .hero {
        min-height: auto;
        padding: 80px 0 64px;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .stats {
        grid-template-columns: repeat(2, 1fr);
    }

    .showcase-item {
        grid-template-columns: 1fr !important;
    }

    .showcase-item:nth-child(even) {
        direction: ltr;
    }
}

@media (max-width: 480px) {
    .stats { grid-template-columns: 1fr; }

    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }
}