:root {
    --primary: #6366f1;
    --primary-soft: #eef2ff;
    --primary-glow: rgba(99, 102, 241, 0.15);
    --secondary: #a855f7;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --bg-main: #f8fafc;
    --card-shadow: 0 20px 50px -12px rgba(0, 0, 0, 0.05);
    --btn-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-main);
    background-image: 
        radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.03) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(168, 85, 247, 0.03) 0px, transparent 50%);
    color: var(--text-main);
    line-height: 1.5;
    min-height: 100vh;
}

.container {
    max-width: 720px;
    margin: 0 auto;
    padding: 4rem 1.5rem;
}

header {
    text-align: center;
    margin-bottom: 4rem;
}

header h1 {
    font-size: 2.75rem;
    font-weight: 900;
    letter-spacing: -0.05em;
    margin-bottom: 0.75rem;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

header p {
    font-size: 1.1rem;
    color: var(--text-muted);
    font-weight: 500;
}

.card {
    background: white;
    padding: 3rem;
    border-radius: 2.5rem;
    box-shadow: var(--card-shadow);
    border: 1px solid rgba(255, 255, 255, 0.8);
}

h2 {
    font-size: 1.5rem;
    font-weight: 800;
    margin-bottom: 2.5rem;
    color: var(--text-main);
    text-align: center;
}

.form-group {
    margin-bottom: 2.5rem;
}

.form-group label {
    display: block;
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* 按钮组网格优化 */
.option-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.option-btn {
    background: #fdfdfd;
    border: 1.5px solid #f1f5f9;
    padding: 1.25rem;
    border-radius: 1.25rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-main);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    position: relative;
    overflow: hidden;
}

.option-btn:hover {
    background: white;
    border-color: var(--primary-light);
    transform: translateY(-2px);
    box-shadow: var(--btn-shadow);
}

.option-btn.active {
    background: white;
    border-color: var(--primary);
    border-width: 2px;
    box-shadow: 0 10px 25px -5px var(--primary-glow);
    color: var(--primary-dark);
}

.option-btn.active::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--primary);
    opacity: 0.03;
}

.option-btn span.emoji {
    font-size: 1.75rem;
    margin-bottom: 0.25rem;
}

/* 文本域优化 */
textarea {
    width: 100%;
    background: #f8fafc;
    border: 1.5px solid #f1f5f9;
    border-radius: 1.25rem;
    padding: 1.25rem;
    font-size: 1rem;
    font-family: inherit;
    resize: none;
    height: 140px;
    transition: var(--transition);
}

textarea:focus {
    outline: none;
    background: white;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px var(--primary-glow);
}

#submit-btn {
    width: 100%;
    background: var(--text-main);
    color: white;
    border: none;
    padding: 1.5rem;
    border-radius: 1.25rem;
    font-size: 1.1rem;
    font-weight: 800;
    cursor: pointer;
    transition: var(--transition);
    margin-top: 1rem;
}

#submit-btn:hover {
    background: #000;
    transform: translateY(-2px);
    box-shadow: 0 20px 30px -10px rgba(0, 0, 0, 0.2);
}

/* 思考过程 - 现代化改造 */
.thinking-container {
    background: #f8fafc;
    border-radius: 1.5rem;
    padding: 1.5rem;
    margin-bottom: 2rem;
    border: 1px dashed #e2e8f0;
    overflow: hidden;
    transition: var(--transition);
}

.thinking-container.collapsed {
    max-height: 60px;
    padding: 1rem 1.5rem;
    opacity: 0.7;
    border: 1px solid #e2e8f0;
}

.status-text {
    font-weight: 700;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.thinking-content {
    font-size: 0.9rem;
    color: var(--text-muted);
    line-height: 1.7;
    margin-top: 1rem;
}

/* 推荐报告渲染 */
.stream-box {
    color: var(--text-main);
}

.stream-box h1, .stream-box h2, .stream-box h3 {
    margin: 2.5rem 0 1.25rem;
    line-height: 1.2;
}

.stream-box h3 {
    font-size: 1.75rem;
    font-weight: 900;
}

.stream-box p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    color: #334155;
}

.stream-box ul {
    list-style: none;
    margin-bottom: 2rem;
}

.stream-box li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 0.75rem;
    font-size: 1.05rem;
}

.stream-box li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--primary);
    font-weight: bold;
}

/* 页脚 */
footer {
    margin-top: 6rem;
    text-align: center;
    padding-bottom: 4rem;
}

footer p {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 600;
}

.loader-sm {
    border: 3px solid #e2e8f0;
    border-top-color: var(--primary);
    width: 18px;
    height: 18px;
}

.hidden { display: none; }

/* 移动端优化 */
@media (max-width: 480px) {
    .container { padding: 2rem 1rem; }
    .card { padding: 1.5rem; }
    header h1 { font-size: 2rem; }
    .option-group { grid-template-columns: 1fr 1fr; }
}

#retry-btn {
    background: #f1f5f9;
    color: var(--text-muted);
    border: 1.5px solid #e2e8f0;
    padding: 1rem;
    border-radius: 1.25rem;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    margin-top: 3rem;
    width: auto;
    display: inline-block;
    padding: 1rem 2.5rem;
}

#retry-btn:hover {
    background: #e2e8f0;
    color: var(--text-main);
    transform: translateY(-1px);
}

.result-card {
    text-align: center;
}

.stream-box h4 { font-size: 1.5rem; margin: 1.5rem 0 1rem; color: var(--text-main); }
.stream-box h5 { font-size: 1.25rem; margin: 1.2rem 0 0.8rem; color: var(--text-main); }
.stream-box h6 { font-size: 1.1rem; margin: 1rem 0 0.5rem; color: var(--text-muted); }
.stream-box hr { border: none; border-top: 2px solid #f1f5f9; margin: 2rem 0; }