/* 全局样式 */
:root {
    --primary-color: #165DFF;
    --secondary-color: #36CFC9;
    --accent-color: #FF7D00;
    --text-color: #333;
    --light-text-color: #666;
    --bg-color: #F5F7FA;
    --card-bg: #FFFFFF;
    --border-color: #E5E6EB;
    --success-color: #00B42A;
    --error-color: #F53F3F;
    --warning-color: #FF7D00;
    --transition: all 0.3s ease;
    --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    --box-shadow-hover: 0 15px 35px rgba(0, 0, 0, 0.12);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.usp-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 40px 20px;
    background: linear-gradient(135deg, #e6f7ff, #f0f9ff);
}

.usp-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    background-color: rgba(255, 255, 255, 0.9);
    border-radius: 16px;
    box-shadow: var(--box-shadow);
    padding: 40px;
}

/* 头部样式 */
.usp-header {
    margin-bottom: 40px;
    text-align: center;
}

.usp-logo {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 15px;
}

.usp-logo i {
    font-size: 32px;
    color: var(--primary-color);
    margin-right: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

.usp-logo span {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-color);
    letter-spacing: 1px;
}

.usp-breadcrumb {
    font-size: 14px;
    color: var(--light-text-color);
}

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

.usp-breadcrumb a:hover {
    text-decoration: underline;
    color: var(--accent-color);
}

.usp-breadcrumb .separator {
    margin: 0 5px;
}

/* 卡片样式 */
.usp-card {
    background-color: var(--card-bg);
    border-radius: 16px;
    box-shadow: var(--box-shadow);
    overflow: hidden;
    margin-bottom: 40px;
    transition: var(--transition);
}

.usp-card:hover {
    box-shadow: var(--box-shadow-hover);
    transform: translateY(-5px);
}

.usp-card-header {
    padding: 40px;
    background: linear-gradient(135deg, var(--primary-color) 0%, #0E42B3 100%);
    color: white;
    text-align: center;
}

.usp-card-header h2 {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.usp-card-header p {
    font-size: 16px;
    color: rgba(255, 255, 255, 0.8);
}

.usp-card-body {
    padding: 40px;
}

/* 表单样式 */
.form-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 30px;
}

.form-group {
    margin-bottom: 20px;
    transition: var(--transition);
}

.form-group.focused .form-input {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(22, 93, 255, 0.2);
}

.form-group label {
    display: block;
    margin-bottom: 10px;
    font-size: 16px;
    font-weight: 500;
}

.form-label {
    display: inline-block;
    margin-right: 5px;
}

.required-indicator {
    color: var(--error-color);
}

.form-input {
    position: relative;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 12px 15px;
    transition: var(--transition);
    background-color: #f9f9f9;
}

.form-input i {
    position: absolute;
    top: 50%;
    left: 15px;
    transform: translateY(-50%);
    color: var(--light-text-color);
    font-size: 18px;
}

.form-input input,
.form-input textarea,
.form-input select {
    width: 100%;
    border: none;
    outline: none;
    font-size: 16px;
    padding-left: 35px;
    background-color: transparent;
}

.form-input textarea {
    min-height: 150px;
    resize: vertical;
}

.form-input select {
    appearance: none;
    -webkit-appearance: none;
    background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12" viewBox="0 0 12 12"><path d="M1 4l5 5 5-5z" fill="%23666666"/></svg>');
    background-repeat: no-repeat;
    background-position: right 15px center;
    background-size: 12px;
}

.form-hint {
    margin-top: 8px;
    font-size: 14px;
    color: var(--light-text-color);
}

/* 按钮样式 */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 16px 30px;
    background: linear-gradient(135deg, var(--primary-color) 0%, #0E42B3 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(22, 93, 255, 0.3);
    width: 100%;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(22, 93, 255, 0.4);
    background: linear-gradient(135deg, #0E42B3 0%, var(--primary-color) 100%);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px rgba(22, 93, 255, 0.3);
}

.btn-primary.loading {
    position: relative;
    color: transparent;
}

.btn-primary.loading::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: translate(-50%, -50%) rotate(360deg);
    }
}

/* 消息提示样式 */
.alert {
    padding: 15px 20px;
    border-radius: 8px;
    font-size: 16px;
    display: flex;
    align-items: center;
    margin-bottom: 20px;
}

.alert-success {
    background-color: rgba(0, 180, 42, 0.1);
    color: var(--success-color);
    border-left: 5px solid var(--success-color);
}

.alert-error {
    background-color: rgba(245, 63, 63, 0.1);
    color: var(--error-color);
    border-left: 5px solid var(--error-color);
}

.alert i {
    margin-right: 10px;
    font-size: 18px;
}

/* 投稿指南样式 */
.usp-guidelines {
    background-color: var(--card-bg);
    border-radius: 16px;
    padding: 30px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
    transition: var(--transition);
}

.usp-guidelines:hover {
    box-shadow: var(--box-shadow-hover);
    transform: translateY(-5px);
}

.usp-guidelines h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--text-color);
    text-align: center;
}

.usp-guidelines ul {
    list-style: none;
    padding-left: 0;
}

.usp-guidelines ul li {
    position: relative;
    padding-left: 25px;
    margin-bottom: 10px;
    color: var(--light-text-color);
}

.usp-guidelines ul li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-size: 18px;
}

/* 响应式设计 */
@media (min-width: 768px) {
    .form-grid {
        grid-template-columns: 1fr;
    }
    
    .usp-card-header {
        padding: 50px;
    }
    
    .usp-card-body {
        padding: 50px;
    }
}

@media (min-width: 992px) {
    .usp-content {
        display: grid;
        grid-template-columns: 3fr 1fr;
        gap: 40px;
    }
    
    .usp-card {
        margin-bottom: 0;
    }
}