/* ==========================================================================
   DARPA 官网官方风格规范 (darpa.mil / USWDS 官方标准视觉系统)
   配色：纯白底色 + DARPA 深海蓝 (#003366) + 科技蓝 (#005EA2) + 典雅灰 (#F8F9FA)
   ========================================================================== */

:root {
    --darpa-navy: #003366;
    --darpa-dark-navy: #002244;
    --darpa-blue: #005EA2;
    --darpa-hover-blue: #1A4480;
    --darpa-cyan: #0284C7;
    --darpa-red: #D9381E;

    --bg-white: #FFFFFF;
    --bg-light: #F8FAFC;
    --bg-subtle: #F1F5F9;
    --border-color: #E2E8F0;
    --border-dark: #CBD5E1;

    --text-main: #0F172A;
    --text-body: #334155;
    --text-muted: #64748B;
    --text-light: #94A3B8;

    --font-sans: -apple-system, BlinkMacSystemFont, "Public Sans", "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    --font-mono: "Roboto Mono", Consolas, Monaco, monospace;

    --radius-sm: 4px;
    --radius-md: 6px;
    --radius-lg: 8px;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.08), 0 2px 4px -2px rgba(0,0,0,0.04);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -4px rgba(0,0,0,0.05);
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-white);
    color: var(--text-main);
    line-height: 1.6;
    font-size: 15px;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1240px;
    margin: 0 auto;
    padding: 0 24px;
}

/* 1. 联邦政府官方标识条 (Official Banner) */
.gov-banner {
    background-color: #F0F2F5;
    border-bottom: 1px solid #E4E7EB;
    padding: 7px 0;
    font-size: 12px;
    color: #333333;
}
.gov-banner-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
}
.gov-banner-left {
    display: flex;
    align-items: center;
    gap: 8px;
}
.gov-flag {
    width: 16px;
    height: 11px;
    background: linear-gradient(to bottom, #d9381e 0%, #d9381e 16%, #fff 16%, #fff 33%, #d9381e 33%, #d9381e 50%, #fff 50%, #fff 66%, #d9381e 66%, #d9381e 83%, #fff 83%, #fff 100%);
    border: 1px solid rgba(0,0,0,0.2);
    position: relative;
    display: inline-block;
}
.gov-flag::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 40%;
    height: 55%;
    background-color: #002855;
}

/* 2. DARPA 官方主头部 (Header) */
.site-header {
    background: #FFFFFF;
    border-bottom: 1px solid var(--border-color);
    padding: 22px 0;
}
.header-flex {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}
.brand-group {
    display: flex;
    align-items: center;
    gap: 18px;
    text-decoration: none;
}
.darpa-logo-big {
    font-size: 36px;
    font-weight: 900;
    letter-spacing: 2px;
    color: var(--darpa-navy);
    line-height: 1;
}
.darpa-title-block {
    border-left: 2px solid var(--border-dark);
    padding-left: 16px;
}
.darpa-title-block h1 {
    font-size: 16px;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: 0.5px;
    line-height: 1.3;
}
.darpa-title-block p {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
}

/* 3. 主导航栏 (Navigation Bar) */
.main-nav {
    background-color: var(--darpa-navy);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-md);
}
.nav-flex {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}
.nav-tabs {
    display: flex;
    list-style: none;
    overflow-x: auto;
}
.nav-tab-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 14px 20px;
    color: #FFFFFF;
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    border: none;
    background: transparent;
    border-bottom: 3px solid transparent;
    transition: all 0.15s ease;
    white-space: nowrap;
}
.nav-tab-btn:hover {
    background-color: var(--darpa-hover-blue);
}
.nav-tab-btn.active {
    background-color: var(--darpa-dark-navy);
    border-bottom: 3px solid #00F0FF;
    color: #FFFFFF;
}

/* 4. 英雄横幅 (Hero Section) */
.hero-section {
    background: linear-gradient(135deg, #002244 0%, #003366 60%, #0B2545 100%);
    color: #FFFFFF;
    padding: 48px 0;
    border-bottom: 4px solid var(--darpa-blue);
    position: relative;
    overflow: hidden;
}
.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 600px;
    height: 100%;
    background: radial-gradient(circle at 80% 50%, rgba(2, 132, 199, 0.15), transparent 70%);
    pointer-events: none;
}
.hero-tag {
    display: inline-block;
    background: rgba(2, 132, 199, 0.25);
    border: 1px solid rgba(2, 132, 199, 0.5);
    color: #38BDF8;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 700;
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
.hero-title {
    font-size: 32px;
    font-weight: 800;
    line-height: 1.3;
    margin-bottom: 16px;
}
.hero-desc {
    font-size: 16px;
    color: #CBD5E1;
    max-width: 920px;
    line-height: 1.7;
    margin-bottom: 28px;
}
.hero-stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.15);
}
.stat-box {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: var(--radius-md);
    padding: 16px;
}
.stat-number {
    font-size: 26px;
    font-weight: 800;
    color: #38BDF8;
    font-family: var(--font-mono);
}
.stat-label {
    font-size: 13px;
    color: #CBD5E1;
    margin-top: 4px;
}

/* 5. 视图切换容器 */
.view-container {
    padding: 40px 0 60px;
}
.tab-pane {
    display: none;
    animation: fadeIn 0.2s ease-in;
}
.tab-pane.active {
    display: block;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(4px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 6. 处室切换栏 (Offices Bar) */
.section-heading-row {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 12px;
}
.section-main-title {
    font-size: 22px;
    font-weight: 800;
    color: var(--darpa-navy);
    display: flex;
    align-items: center;
    gap: 10px;
}
.section-main-title::before {
    content: '';
    display: inline-block;
    width: 5px;
    height: 22px;
    background: var(--darpa-blue);
    border-radius: 2px;
}
.offices-cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 12px;
    margin-bottom: 28px;
}
.office-tab-card {
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 14px;
    cursor: pointer;
    transition: all 0.15s ease;
}
.office-tab-card:hover {
    border-color: var(--darpa-blue);
    background: #FFFFFF;
    box-shadow: var(--shadow-sm);
    transform: translateY(-2px);
}
.office-tab-card.active {
    border-color: var(--darpa-blue);
    background: #EFF6FF;
    border-left: 4px solid var(--darpa-blue);
    box-shadow: var(--shadow-sm);
}
.office-code {
    font-size: 16px;
    font-weight: 800;
    color: var(--darpa-navy);
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.office-count-badge {
    font-size: 11px;
    background: #E2E8F0;
    color: var(--text-body);
    padding: 2px 7px;
    border-radius: 12px;
    font-family: var(--font-mono);
}
.office-name-zh {
    font-size: 13px;
    font-weight: 700;
    color: var(--text-main);
    margin-top: 4px;
}
.office-desc-short {
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 4px;
    line-height: 1.4;
}

/* 7. 搜索与筛选工具栏 (Filter Bar) */
.filter-toolbar {
    background: #F8FAFC;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    margin-bottom: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 14px;
}
.search-box-wrap {
    flex: 1;
    min-width: 280px;
    position: relative;
}
.search-input-field {
    width: 100%;
    padding: 10px 14px 10px 36px;
    border: 1px solid var(--border-dark);
    border-radius: var(--radius-sm);
    font-size: 14px;
    color: var(--text-main);
    background: #FFFFFF;
}
.search-input-field:focus {
    outline: 2px solid var(--darpa-blue);
    border-color: var(--darpa-blue);
}
.search-icon-svg {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    pointer-events: none;
}
.select-box-styled {
    padding: 9px 14px;
    border: 1px solid var(--border-dark);
    border-radius: var(--radius-sm);
    font-size: 13px;
    color: var(--text-main);
    background: #FFFFFF;
    cursor: pointer;
}

/* 8. BAA 卡片网格 (BAA Cards Grid) */
.baa-cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(380px, 1fr));
    gap: 24px;
    margin-bottom: 40px;
}
.baa-item-card {
    background: #FFFFFF;
    border: 1px solid var(--border-color);
    border-top: 4px solid var(--darpa-navy);
    border-radius: var(--radius-md);
    padding: 24px;
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: all 0.2s ease;
}
.baa-item-card:hover {
    border-top-color: var(--darpa-blue);
    box-shadow: var(--shadow-lg);
    transform: translateY(-3px);
}
.baa-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}
.baa-num-badge {
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 700;
    color: var(--darpa-navy);
    background: #EFF6FF;
    border: 1px solid #BFDBFE;
    padding: 3px 8px;
    border-radius: 4px;
}
.baa-status-tag {
    font-size: 11px;
    font-weight: 700;
    padding: 3px 8px;
    border-radius: 4px;
}
.status-open {
    background: #DCFCE7;
    color: #166534;
    border: 1px solid #86EFAC;
}
.status-closing {
    background: #FEF3C7;
    color: #92400E;
    border: 1px solid #FCD34D;
}
.status-rolling {
    background: #E0E7FF;
    color: #3730A3;
    border: 1px solid #A5B4FC;
}
.baa-title-zh {
    font-size: 18px;
    font-weight: 800;
    color: var(--darpa-navy);
    line-height: 1.4;
    margin-bottom: 6px;
}
.baa-title-en {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: 12px;
    font-family: var(--font-mono);
}
.baa-desc-text {
    font-size: 13px;
    color: var(--text-body);
    line-height: 1.6;
    margin-bottom: 16px;
    flex-grow: 1;
}
.baa-tags-wrap {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 16px;
}
.baa-tech-tag {
    font-size: 11px;
    background: #F1F5F9;
    color: var(--text-body);
    padding: 2px 8px;
    border-radius: 3px;
    border: 1px solid #E2E8F0;
}
.baa-meta-table {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    padding: 12px 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 16px;
    font-size: 12px;
}
.meta-row-label {
    color: var(--text-muted);
    font-size: 11px;
}
.meta-row-value {
    color: var(--text-main);
    font-weight: 700;
    font-family: var(--font-mono);
}
.btn-view-details {
    width: 100%;
    background: #FFFFFF;
    border: 1px solid var(--darpa-blue);
    color: var(--darpa-blue);
    padding: 9px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.15s ease;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 6px;
}
.btn-view-details:hover {
    background: var(--darpa-blue);
    color: #FFFFFF;
}

/* 9. 海尔迈耶问卷与操作指南容器 */
.white-card-block {
    background: #FFFFFF;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 32px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 32px;
}
.heilmeier-intro {
    background: #EFF6FF;
    border-left: 4px solid var(--darpa-blue);
    padding: 18px;
    border-radius: 4px;
    font-size: 14px;
    color: #1E3A8A;
    line-height: 1.7;
    margin-bottom: 28px;
}
.questions-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 28px;
}
@media (max-width: 860px) {
    .questions-list {
        grid-template-columns: 1fr;
    }
}
.question-box {
    background: #F8FAFC;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 20px;
}
.q-title-row {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 15px;
    font-weight: 800;
    color: var(--darpa-navy);
    margin-bottom: 8px;
}
.q-badge {
    background: var(--darpa-navy);
    color: #FFFFFF;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: inline-flex;
    justify-content: center;
    align-items: center;
    font-size: 12px;
    font-weight: 800;
    font-family: var(--font-mono);
}
.q-desc {
    font-size: 13px;
    color: var(--text-body);
    line-height: 1.6;
    margin-bottom: 12px;
}
.q-example {
    background: #FFFFFF;
    border-left: 3px solid #94A3B8;
    padding: 8px 12px;
    font-size: 12px;
    color: #475569;
    line-height: 1.5;
}

/* 10. BAAT 登录与提交通道样式 */
.dod-notice-box {
    background: #FFFBEB;
    border: 1px solid #FCD34D;
    border-left: 6px solid #D97706;
    border-radius: var(--radius-sm);
    padding: 20px 24px;
    margin-bottom: 28px;
    box-shadow: var(--shadow-sm);
}
.dod-notice-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 15px;
    font-weight: 800;
    color: #92400E;
    margin-bottom: 8px;
}
.dod-notice-content {
    font-size: 13px;
    color: #78350F;
    line-height: 1.7;
}
.two-col-grid {
    display: grid;
    grid-template-columns: 1.15fr 1fr;
    gap: 28px;
}
@media (max-width: 920px) {
    .two-col-grid {
        grid-template-columns: 1fr;
    }
}
.darpa-card {
    background: #FFFFFF;
    border: 1px solid var(--border-color);
    border-top: 4px solid var(--darpa-navy);
    border-radius: var(--radius-md);
    padding: 28px;
    box-shadow: var(--shadow-sm);
}
.darpa-card h2 {
    font-size: 20px;
    font-weight: 800;
    color: var(--darpa-navy);
    margin-bottom: 6px;
}
.darpa-card-desc {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 20px;
}
.login-field {
    margin-bottom: 18px;
}
.login-field label {
    display: block;
    font-size: 13px;
    font-weight: 700;
    color: var(--darpa-navy);
    margin-bottom: 6px;
}
.login-input {
    width: 100%;
    padding: 12px 14px;
    border: 1.5px solid var(--border-dark);
    border-radius: var(--radius-sm);
    font-size: 14px;
    color: var(--text-main);
    background: #FFFFFF;
    transition: all 0.15s ease;
    box-sizing: border-box;
}
.login-input:focus {
    outline: none;
    border-color: var(--darpa-blue);
    box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.2);
}
.login-btn-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 14px;
    margin-top: 24px;
}
.btn-darpa {
    background: var(--darpa-navy);
    color: #FFFFFF;
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.15s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}
.btn-darpa:hover {
    background: var(--darpa-blue);
}
.btn-darpa:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}
.login-links {
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 12px;
}
.login-links a {
    color: var(--darpa-blue);
    text-decoration: none;
    font-weight: 600;
}
.login-links a:hover {
    text-decoration: underline;
}
.registration-info-box {
    background: #F8FAFC;
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--darpa-blue);
    border-radius: 4px;
    padding: 18px;
    margin-top: 24px;
}
.registration-info-box h3 {
    font-size: 14px;
    font-weight: 800;
    color: var(--darpa-navy);
    margin-bottom: 10px;
}
.registration-info-box ol {
    padding-left: 20px;
    font-size: 13px;
    color: var(--text-body);
    line-height: 1.7;
}
.guide-item {
    background: #F8FAFC;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 14px 16px;
    margin-bottom: 12px;
}
.guide-item h4 {
    font-size: 14px;
    font-weight: 700;
    color: var(--darpa-navy);
    margin-bottom: 4px;
}
.guide-item p {
    font-size: 13px;
    color: var(--text-body);
    line-height: 1.6;
}

/* 头部与横幅显要入口按钮 */
.btn-header-login {
    background: var(--darpa-navy);
    color: #FFFFFF;
    border: 1px solid var(--darpa-blue);
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: all 0.15s ease;
}
.btn-header-login:hover {
    background: var(--darpa-blue);
    color: #FFFFFF;
    box-shadow: var(--shadow-sm);
}
.nav-login-btn {
    background: #0284C7;
    color: #FFFFFF;
    border: none;
    padding: 8px 16px;
    border-radius: 4px;
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: all 0.15s ease;
}
.nav-login-btn:hover {
    background: #0369A1;
}
.btn-hero-primary {
    background: var(--darpa-blue);
    color: #FFFFFF;
    border: none;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: all 0.15s ease;
}
.btn-hero-primary:hover {
    background: #026aa2;
}
.btn-hero-secondary {
    background: rgba(255, 255, 255, 0.12);
    color: #FFFFFF;
    border: 1.5px solid rgba(255, 255, 255, 0.4);
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    backdrop-filter: blur(4px);
    transition: all 0.15s ease;
}
.btn-hero-secondary:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: #FFFFFF;
}

/* 11. 弹窗模态框 (Modal) */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(4px);
    z-index: 1000;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 20px;
}
.modal-overlay.active {
    display: flex;
}
.modal-content-box {
    background: #FFFFFF;
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 820px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
}
.modal-header-bar {
    background: #F8FAFC;
    padding: 18px 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.modal-header-bar h3 {
    font-size: 18px;
    font-weight: 800;
    color: var(--darpa-navy);
}
.btn-close-modal {
    background: transparent;
    border: none;
    font-size: 24px;
    color: var(--text-muted);
    cursor: pointer;
}
.btn-close-modal:hover {
    color: var(--text-main);
}
.modal-body-content {
    padding: 24px;
}

/* 11. 页脚 (Footer) */
.site-footer {
    background-color: var(--darpa-dark-navy);
    color: #CBD5E1;
    padding: 48px 0 28px;
    border-top: 4px solid var(--darpa-blue);
    font-size: 13px;
}
.footer-row-main {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 32px;
    margin-bottom: 36px;
    padding-bottom: 28px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}
.footer-links-col h4 {
    color: #FFFFFF;
    font-size: 15px;
    margin-bottom: 12px;
}
.footer-links-col ul {
    list-style: none;
}
.footer-links-col li {
    margin-bottom: 8px;
}
.footer-links-col a {
    color: #94A3B8;
    text-decoration: none;
    transition: color 0.15s;
}
.footer-links-col a:hover {
    color: #38BDF8;
    text-decoration: underline;
}
.footer-bottom-copy {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    font-size: 12px;
    color: #64748B;
}