/* Reset & Base Styles */
:root {
    --bg-primary: #0a192f;
    --bg-secondary: #112240;
    --bg-tertiary: #233554;
    --text-primary: #ccd6f6;
    --text-secondary: #8892b0;
    --accent: #64ffda;
    --accent-glow: rgba(100, 255, 218, 0.1);
    --white: #ffffff;
    --transition: all 0.3s ease;
    --nav-height: 80px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

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

ul {
    list-style: none;
}

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

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-padding {
    padding: 100px 0;
}

h1, h2, h3, h4 {
    color: var(--text-primary);
    font-weight: 700;
    line-height: 1.1;
}

p {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 4px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary {
    background-color: transparent;
    border: 1px solid var(--accent);
    color: var(--accent);
}

.btn-primary:hover {
    background-color: var(--accent-glow);
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: var(--bg-tertiary);
    color: var(--white);
    border: 1px solid var(--bg-tertiary);
    margin-left: 15px;
}

.btn-secondary:hover {
    background-color: var(--bg-secondary);
    transform: translateY(-2px);
}

.btn-lg {
    padding: 15px 40px;
    font-size: 1.1rem;
}

.btn-outline {
    border: 1px solid var(--text-secondary);
    color: var(--text-secondary);
    margin-left: 15px;
}

.btn-outline:hover {
    border-color: var(--accent);
    color: var(--accent);
}

/* Navbar */
.navbar {
    height: var(--nav-height);
    background-color: rgba(10, 25, 47, 0.95);
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    box-shadow: 0 10px 30px -10px rgba(2, 12, 27, 0.7);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent);
}

.logo a {
    display: inline-flex;
    align-items: center;
}

.logo-icon {
    margin-right: 10px;
    font-size: 1.8rem;
}

.nav-links {
    display: flex;
    align-items: center;
}

.nav-links li {
    margin: 0 15px;
}

.nav-links a {
    font-size: 0.9rem;
    font-weight: 500;
}

.nav-links a:hover {
    color: var(--accent);
}

.nav-links a.active {
    color: var(--accent);
}

.btn-nav {
    padding: 8px 16px;
    border: 1px solid var(--accent);
    border-radius: 4px;
    color: var(--accent);
}

.btn-nav:hover {
    background-color: var(--accent-glow);
}

.menu-toggle {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-primary);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    padding-top: var(--nav-height);
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to right, rgba(10, 25, 47, 0.9), rgba(10, 25, 47, 0.65));
    z-index: 1;
}

.hero-bg-placeholder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    background: url('../image/hero_bg_placeholder.jpg') no-repeat center center/cover;
}

.hero-bg-video {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    min-width: 100%;
    min-height: 100%;
    width: auto;
    height: auto;
    object-fit: cover;
    z-index: -1;
}

.abstract-bg {
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 50% 50%, #112240 0%, #0a192f 100%);
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.hero h1 {
    font-size: clamp(40px, 8vw, 80px);
    margin-bottom: 20px;
    color: var(--text-primary);
}

.hero p {
    font-size: clamp(18px, 3vw, 24px);
    max-width: 600px;
    margin-bottom: 40px;
}

/* Features Intro */
.features-intro {
    background-color: var(--bg-primary);
}

.section-header {
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 15px;
    position: relative;
    display: inline-block;
}

.section-header h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background-color: var(--accent);
    margin: 10px auto 0;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    background-color: var(--bg-secondary);
    padding: 30px;
    border-radius: 6px;
    transition: var(--transition);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 30px -15px rgba(2, 12, 27, 0.7);
}

.icon-box {
    font-size: 3rem;
    color: var(--accent);
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
}

/* Metrics Section */
.metrics-section {
    background-color: var(--bg-tertiary);
}

.metrics-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 30px;
}

.metrics-column {
    flex: 1 1 260px;
}

.metrics-column-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.metrics-illustration {
    margin-bottom: 18px;
    border-radius: 8px;
    overflow: hidden;
    background: radial-gradient(circle at top left, rgba(100, 255, 218, 0.12), transparent 60%);
    height: 170px;
}

.metrics-illustration img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.metric-card {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: 30px 24px;
    text-align: center;
    border: 1px solid var(--accent-glow);
    box-shadow: 0 20px 40px -20px rgba(2, 12, 27, 0.9);
}

.metric-value {
    font-size: 2.4rem;
    font-weight: 800;
    color: var(--accent);
    margin-bottom: 10px;
}

.metric-label {
    font-size: 0.95rem;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.metric-note {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* Solutions Section */
.bg-dark {
    background-color: var(--bg-secondary);
}

.solution-block {
    display: flex;
    align-items: center;
    margin-bottom: 100px;
    gap: 50px;
}

.solution-block.reverse {
    flex-direction: row-reverse;
}

.solution-content {
    flex: 1;
}

.solution-image {
    flex: 1;
    position: relative;
}

.img-placeholder {
    width: 100%;
    height: auto;
    background-color: var(--bg-tertiary);
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: var(--text-secondary);
    border: 2px dashed var(--text-secondary);
    position: relative;
    overflow: hidden;
    transition: var(--transition);
}

.img-placeholder:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.img-placeholder img {
    max-width: 100%;
    max-height: 100%;
    width: auto;
    height: auto;
    object-fit: contain;
    position: static;
}

.tag {
    color: var(--accent);
    font-family: monospace;
    font-size: 0.9rem;
    margin-bottom: 10px;
    display: block;
}

.solution-content h3 {
    font-size: 2rem;
    margin-bottom: 20px;
}

.solution-list {
    margin-bottom: 30px;
}

.solution-list li {
    margin-bottom: 15px;
    display: flex;
    align-items: flex-start;
}

.solution-list i {
    color: var(--accent);
    margin-right: 10px;
    margin-top: 5px;
}

.btn-text {
    color: var(--accent);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
}

.btn-text i {
    margin-left: 5px;
    transition: var(--transition);
}

.btn-text:hover {
    text-decoration: underline;
}

.btn-text:hover i {
    transform: translateX(5px);
}

/* Tech Details */
.tech-details {
    background-color: var(--bg-primary);
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.tech-item {
    background-color: var(--bg-secondary);
    border-radius: 6px;
    overflow: hidden;
}

.tech-img-placeholder {
    height: 200px;
    background-color: var(--bg-tertiary);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 4rem;
    color: var(--text-secondary);
}

.tech-img-placeholder img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.tech-info {
    padding: 25px;
}

.tech-info h4 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: var(--white);
}

/* CTA Section */
.cta-section {
    padding: 100px 0;
    background-color: var(--bg-tertiary);
}

.cta-section h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: var(--white);
}

.cta-btns {
    margin-top: 40px;
}

/* Modal (申请工程应用) */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(2, 12, 27, 0.85);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1100;
}

.modal-overlay.active {
    display: flex;
}

.modal {
    background: var(--bg-secondary);
    border-radius: 8px;
    width: 90%;
    max-width: 520px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.7);
    border: 1px solid var(--accent-glow);
    animation: fadeInUp 0.3s ease forwards;
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 18px 24px;
    border-bottom: 1px solid var(--bg-tertiary);
}

.modal-header h3 {
    font-size: 1.3rem;
}

.modal-close {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 1.2rem;
}

.modal-close:hover {
    color: var(--accent);
}

.modal-body {
    padding: 16px 24px 0 24px;
}

.modal-body p {
    margin-bottom: 16px;
}

#engineering-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

#engineering-form label {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

#engineering-form input,
#engineering-form textarea {
    margin-top: 4px;
    padding: 8px 10px;
    border-radius: 4px;
    border: 1px solid var(--bg-tertiary);
    background: #020c1b;
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.95rem;
}

#engineering-form input:focus,
#engineering-form textarea:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 1px var(--accent-glow);
}

.modal-actions {
    padding: 16px 24px 20px 24px;
    border-top: 1px solid var(--bg-tertiary);
    text-align: right;
}

.modal-actions .btn {
    min-width: 120px;
}

/* =======================
   Engineering Page Styles
   ======================= */

/* Inner hero for engineering page */
.hero.hero-inner {
    min-height: 70vh;
    padding-bottom: 60px;
}

.hero.hero-inner .hero-content {
    max-width: 900px;
}

.hero-bullets ul {
    /* 工程仿真页面：这里希望三条描述竖向一行一个，而不是自动多列排布 */
    display: block;
}

.hero-bullets li {
    display: flex;
    align-items: flex-start;
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.hero-bullets {
    margin-top: 12px;
    margin-bottom: 20px;
}

.hero-bullets i {
    color: var(--accent);
    margin-right: 8px;
    margin-top: 4px;
}

.hero-bg-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.35;
}

/* 子页面（带 hero-inner）的英雄图整体提亮 */
.hero.hero-inner .hero-overlay {
    background: linear-gradient(to right, rgba(10, 25, 47, 0.75), rgba(10, 25, 47, 0.35));
}

.hero.hero-inner .hero-bg-image {
    opacity: 0.65;
}

/* Workflow section */
.workflow-grid {
    display: grid;
    grid-template-columns: minmax(0, 2.1fr) minmax(0, 1.9fr);
    gap: 36px;
    align-items: stretch;
}

.workflow-steps {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.step {
    position: relative;
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: 14px 16px 14px 20px;
    border: 1px solid rgba(100, 255, 218, 0.08);
}

.step-index {
    position: absolute;
    left: 16px;
    top: 14px;
    width: 24px;
    height: 24px;
    border-radius: 999px;
    border: 1px solid var(--accent);
    color: var(--accent);
    font-size: 0.8rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.step h4,
.step p {
    margin-left: 40px;
}

.workflow-figure {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: 18px;
    border: 1px solid var(--accent-glow);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.workflow-figure .img-responsive {
    width: 100%;
    height: auto;
    border-radius: 6px;
}

.img-caption {
    margin-top: 10px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-align: center;
}

.case-highlight {
    display: flex;
    gap: 32px;
    align-items: flex-start;
    margin-bottom: 40px;
}

.case-image {
    flex: 1;
}

.case-image img {
    width: 100%;
    height: 320px;
    object-fit: contain;
}

.case-info {
    flex: 1.2;
}

.case-metrics {
    margin: 16px 0 16px;
    padding-left: 18px;
}

.case-metrics li {
    margin-bottom: 8px;
}

.case-list ul {
    padding-left: 18px;
}

.case-list li {
    margin-bottom: 8px;
}

.case-list h4 {
    margin-bottom: 16px;
}

.case-more {
    display: flex;
    gap: 32px;
    align-items: flex-start;
    margin-top: 24px;
}

.case-extra-image {
    flex: 0.8;
    min-width: 260px;
    max-width: 420px;
}

.case-extra-image img {
    border-radius: 8px;
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.table-engineering {
    width: 100%;
    min-width: 720px;
    border-collapse: collapse;
    background-color: var(--bg-secondary);
    border-radius: 8px;
    overflow: hidden;
}

.table-engineering thead {
    background-color: var(--bg-tertiary);
}

.table-engineering th,
.table-engineering td {
    padding: 14px 16px;
    border-bottom: 1px solid var(--bg-tertiary);
    font-size: 0.9rem;
    text-align: center;
    vertical-align: middle;
}

.table-engineering th {
    color: var(--white);
    white-space: nowrap;
}

.table-engineering td:first-child {
    white-space: nowrap;
}

/* Environment cards */
.env-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.env-card {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: 24px;
    border: 1px solid rgba(100, 255, 218, 0.08);
}

.env-card h3 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.env-card i {
    color: var(--accent);
}

.env-card ul {
    padding-left: 18px;
}

.env-card li {
    margin-bottom: 8px;
}

/* Experience cards */
.exp-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.exp-card {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: 20px;
    border: 1px solid rgba(100, 255, 218, 0.06);
    transition: var(--transition);
}

.exp-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 18px 28px -18px rgba(2, 12, 27, 0.9);
}

.exp-img {
    border-radius: 6px;
    margin-bottom: 16px;
}

.exp-card h4 {
    margin-bottom: 8px;
}

/* Feedback section */
.feedback-grid {
    display: grid;
    grid-template-columns: 2fr 1.4fr;
    gap: 24px;
    align-items: center;
}

.feedback-photo {
    border-radius: 8px;
    overflow: hidden;
}

.feedback-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.feedback-text ul {
    padding-left: 18px;
}

.feedback-text li {
    margin-bottom: 8px;
}

/* Device section */
.device-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 24px;
}

.device-card {
    background-color: var(--bg-tertiary);
    border-radius: 8px;
    padding: 24px;
    text-align: center;
    border: 1px solid rgba(100, 255, 218, 0.06);
}

.device-card i {
    font-size: 2rem;
    color: var(--accent);
    margin-bottom: 12px;
}

.device-card h4 {
    margin-bottom: 8px;
}

/* Case logo section */
.case-logo-marquee {
    overflow: hidden;
    margin-bottom: 24px;
}

.case-logo-track {
    display: flex;
    align-items: center;
    gap: 32px;
    width: max-content;
    animation: logo-scroll 25s linear infinite;
}

.case-logo-card {
    background-color: #ffffff;
    border-radius: 10px;
    padding: 10px 18px;
    box-shadow: 0 10px 25px -15px rgba(2, 12, 27, 0.9);
}

.case-logo {
    max-height: 48px;
    width: auto;
    object-fit: contain;
    display: block;
}

@keyframes logo-scroll {
    from {
        transform: translateX(0);
    }
    to {
        transform: translateX(-50%);
    }
}

/* Footer */
footer {
    background-color: #020c1b;
    padding-top: 60px;
    padding-bottom: 30px;
    text-align: center;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 60px;
    text-align: left;
}

.footer-brand h3 {
    color: var(--white);
    margin-bottom: 10px;
}

.footer-links h4 {
    color: var(--white);
    margin-bottom: 20px;
    font-size: 1.1rem;
}

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

.footer-links a:hover {
    color: var(--accent);
}

.footer-bottom {
    border-top: 1px solid var(--bg-tertiary);
    padding-top: 30px;
    font-size: 0.9rem;
}

/* Beian bar (shown near footer, not fixed) */
.beian-bar {
    background-color: #020c1b;
    border-top: 1px solid var(--bg-tertiary);
    padding: 8px 0;
}

.beian-bar-inner {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 24px;
    text-align: center;
}

.beian-link {
    display: flex;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.beian-link:hover {
    color: var(--accent);
}

.beian-icon {
    width: 16px;
    height: 16px;
    margin-right: 4px;
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-up {
    opacity: 0;
    animation: fadeInUp 0.8s ease forwards;
}

.delay-1 { animation-delay: 0.2s; }
.delay-2 { animation-delay: 0.4s; }

/* Responsive */
@media (max-width: 768px) {
    .navbar .container {
        padding: 0 20px;
    }

    .nav-links {
        position: fixed;
        top: var(--nav-height);
        right: 0;
        height: calc(100vh - var(--nav-height));
        background-color: var(--bg-secondary);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        width: 70%;
        transform: translateX(100%);
        transition: var(--transition);
    }

    .nav-links.active {
        transform: translateX(0);
    }

    .nav-links li {
        margin: 20px 0;
    }

    .menu-toggle {
        display: block;
    }

    .hero h1 {
        font-size: 40px;
    }

    .solution-block, .solution-block.reverse {
        flex-direction: column;
        text-align: center;
    }

    .solution-list {
        text-align: left;
        display: inline-block;
    }
}