:root {
    --ai-bg: #141c2e;
    --ai-surface: #1e2a42;
    --ai-surface-elevated: #263552;
    --ai-surface-border: rgba(148, 180, 220, 0.28);
    --ai-text: #f4f7fc;
    --ai-text-muted: #b8c5d9;
    --ai-accent: #6366f1;
    --ai-accent-2: #38bdf8;
    --ai-gradient: linear-gradient(135deg, #6366f1 0%, #38bdf8 50%, #a78bfa 100%);
    --ai-shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
    --ai-radius: 16px;
    --ai-font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    font-family: var(--ai-font);
    background: var(--ai-bg);
    color: var(--ai-text);
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
}

/* 背景网格与光晕 */
.ai-bg-grid {
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(rgba(99, 102, 241, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(99, 102, 241, 0.03) 1px, transparent 1px);
    background-size: 48px 48px;
    pointer-events: none;
    z-index: 0;
}

.ai-glow {
    position: fixed;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.22;
    pointer-events: none;
    z-index: 0;
}

.ai-glow-1 {
    width: 400px;
    height: 400px;
    background: #6366f1;
    top: -100px;
    right: -100px;
}

.ai-glow-2 {
    width: 350px;
    height: 350px;
    background: #22d3ee;
    bottom: -80px;
    left: -80px;
}

main,
nav,
footer {
    position: relative;
    z-index: 1;
}

/* 导航栏 */
.ai-navbar {
    background: rgba(30, 42, 66, 0.92) !important;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--ai-surface-border);
    margin-bottom: 0;
    padding: 0.75rem 1.5rem;
}

.ai-brand {
    font-weight: 600;
    font-size: 1.05rem;
    color: var(--ai-text) !important;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.ai-brand-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: var(--ai-gradient);
    border-radius: 8px;
    font-size: 0.75rem;
    color: #fff;
}

.ai-nav-link {
    color: var(--ai-text-muted) !important;
    font-weight: 500;
    transition: color 0.2s;
}

.ai-nav-link:hover {
    color: var(--ai-accent-2) !important;
}

.ai-navbar-toggler {
    border-color: var(--ai-surface-border);
}

.ai-dropdown {
    background: var(--ai-surface-elevated);
    border: 1px solid var(--ai-surface-border);
    border-radius: 12px;
    box-shadow: var(--ai-shadow);
    padding: 0.35rem;
}

.ai-dropdown-item {
    color: var(--ai-text);
    border-radius: 8px;
    padding: 0.5rem 1rem;
}

.ai-dropdown-item:hover {
    background: rgba(99, 102, 241, 0.2);
    color: var(--ai-accent-2);
}

/* Hero */
.ai-hero {
    text-align: center;
    padding: 2.5rem 1rem 1.5rem;
    max-width: 560px;
    margin: 0 auto;
}

.ai-hero-badge {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ai-accent-2);
    background: rgba(34, 211, 238, 0.1);
    border: 1px solid rgba(34, 211, 238, 0.25);
    border-radius: 999px;
    padding: 0.35rem 0.9rem;
    margin-bottom: 1rem;
}

.ai-hero-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--ai-text);
}

.ai-hero-desc {
    color: var(--ai-text-muted);
    font-size: 0.95rem;
    line-height: 1.65;
    margin: 0;
}

/* 主卡片 */
.ai-card {
    background: var(--ai-surface);
    border: 1px solid var(--ai-surface-border);
    border-radius: var(--ai-radius);
    padding: 1.75rem;
    box-shadow: var(--ai-shadow);
    max-width: 720px;
    margin: 0 auto 3rem;
}

.ai-btn-primary {
    background: var(--ai-gradient) !important;
    border: none !important;
    color: #fff !important;
    font-weight: 600;
    border-radius: 12px !important;
    padding: 0.85rem 1.5rem !important;
    transition: transform 0.2s, box-shadow 0.2s;
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.35);
}

.ai-btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 28px rgba(99, 102, 241, 0.45);
    color: #fff !important;
}

.ai-btn-icon {
    margin-right: 0.35rem;
    opacity: 0.9;
}

.ai-upload-hint {
    text-align: center;
    color: var(--ai-text-muted);
    font-size: 0.8rem;
    margin: 0.75rem 0 0;
}

.ai-btn-ghost {
    background: rgba(99, 102, 241, 0.2) !important;
    border: 1px solid var(--ai-surface-border) !important;
    color: #fff !important;
    font-weight: 500;
    border-radius: 10px !important;
    transition: background 0.2s, border-color 0.2s;
}

.ai-btn-ghost:hover {
    background: rgba(99, 102, 241, 0.22) !important;
    border-color: rgba(34, 211, 238, 0.35) !important;
    color: var(--ai-accent-2) !important;
}

.ai-btn-secondary {
    background: rgba(99, 102, 241, 0.4) !important;
    border: 1px solid rgba(148, 180, 220, 0.45) !important;
    color: #fff !important;
    font-weight: 600;
    border-radius: 10px !important;
}

.ai-btn-secondary:hover {
    background: rgba(99, 102, 241, 0.55) !important;
    color: #fff !important;
}

/* 模式切换（选择图片下方） */
.mode-toolbar {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--ai-surface-border);
}

.mode-toolbar .switchButtonsGroup {
    margin-bottom: 0.75rem;
}

.mode-toolbar .ai-mode-badge {
    margin-top: 0;
}

/* 预览区 */
.handle-container {
    margin-top: 1rem;
}

.ai-preview-frame {
    background: #0f1520;
    border: 1px solid var(--ai-surface-border);
    border-radius: 12px;
    padding: 0.75rem;
    margin-bottom: 1rem;
    overflow: hidden;
}

.finalImage {
    max-width: 100%;
    display: block;
    margin: 0 auto;
    border-radius: 8px;
}

.switchButtonsGroup {
    width: 100%;
    gap: 0.5rem;
    display: flex;
}

.switchButton {
    flex: 1;
    width: auto !important;
}

.ai-mode-badge {
    width: 100%;
    display: inline-block;
    text-align: center;
    margin: 1rem 0 0;
    padding: 0.5rem 1rem;
    font-size: 0.95rem;
    font-weight: 600;
    color: #7dd3fc;
    background: rgba(56, 189, 248, 0.15);
    border: 1px solid rgba(56, 189, 248, 0.35);
    border-radius: 999px;
}

/* 模态框 — 不透明背景，高对比文字 */
.modal {
    z-index: 1050;
}

.modal-backdrop.show {
    opacity: 0.82;
    background-color: #0a0f18;
}

.ai-modal {
    background: var(--ai-surface-elevated) !important;
    border: 1px solid var(--ai-surface-border);
    border-radius: var(--ai-radius);
    color: var(--ai-text) !important;
    box-shadow: 0 24px 64px rgba(0, 0, 0, 0.55);
}

.ai-modal .modal-header,
.ai-modal .modal-body,
.ai-modal .modal-footer {
    background: transparent !important;
    color: var(--ai-text) !important;
}

.ai-modal-header,
.ai-modal-footer {
    border: none;
    padding: 1.25rem 1.5rem;
}

.ai-modal-header {
    border-bottom: 1px solid var(--ai-surface-border);
}

.ai-modal-header .modal-title {
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--ai-text) !important;
}

.ai-modal-body {
    padding: 1.25rem 1.5rem 1.5rem;
    color: var(--ai-text) !important;
    line-height: 1.75;
    font-size: 0.95rem;
}

.ai-modal-body p {
    color: var(--ai-text) !important;
    margin-bottom: 0.85rem;
}

.ai-modal-body strong {
    color: #fff !important;
    font-weight: 600;
}

.ai-modal-body ul {
    padding-left: 1.25rem;
    margin: 0.5rem 0 1rem;
    color: var(--ai-text) !important;
}

.ai-modal-body li {
    margin-bottom: 0.5rem;
    color: var(--ai-text) !important;
}

.ai-modal-tip {
    margin-top: 0.5rem;
    margin-bottom: 0;
    padding: 0.85rem 1rem;
    background: rgba(99, 102, 241, 0.22);
    border: 1px solid rgba(99, 102, 241, 0.35);
    border-radius: 8px;
    font-size: 0.9rem;
    color: var(--ai-text) !important;
}

.ai-modal-body kbd {
    display: inline-block;
    padding: 0.2rem 0.45rem;
    font-size: 0.85em;
    font-weight: 600;
    background: rgba(56, 189, 248, 0.2);
    border: 1px solid rgba(56, 189, 248, 0.45);
    border-radius: 4px;
    color: #7dd3fc !important;
}

/* Footer */
.ai-footer {
    padding: 1.5rem;
    color: var(--ai-text-muted);
    font-size: 0.85rem;
}

.ai-footer p {
    margin: 0;
}

/* 覆盖 Bootstrap 默认 */
.jumbotron {
    background: transparent;
    padding: 0;
    margin: 0;
}

.container {
    max-width: 800px;
}

@media (max-width: 576px) {
    .ai-hero-title {
        font-size: 1.4rem;
    }

    .ai-card {
        padding: 1.25rem;
        margin-left: 0.75rem;
        margin-right: 0.75rem;
    }

    .switchButton span {
        display: none;
    }
}