:root {
    --primary-color: #007bff;
    --primary-hover: #0056b3;
    --secondary-color: #6c757d;
    --background-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-main: #333;
    --text-secondary: #666;
    --border-color: #ddd;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --error-color: #dc3545;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-md: 4px;
    --radius-lg: 8px;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-main);
    line-height: 1.6;
    display: flex;
    justify-content: center;
    min-height: 100vh;
    padding: 2rem 1rem;
}

.container {
    width: 100%;
    max-width: 800px;
}

header {
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeInDown 0.6s ease-out;
}

header h1 {
    font-size: 2.25rem;
    font-weight: 700;
    color: #007bff;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
}

header h1 i {
    color: var(--primary-color);
}

.description {
    color: var(--text-secondary);
    font-size: 1rem;
    max-width: 600px;
    margin: 0 auto;
}

.card {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: 2rem;
    margin-bottom: 2rem;
    border: 1px solid var(--border-color);
    transition: transform 0.2s, box-shadow 0.2s;
}

.search-card:hover {
    box-shadow: var(--shadow-lg);
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.input-wrapper,
.select-wrapper {
    position: relative;
}

.input-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--secondary-color);
    pointer-events: none;
}

input[type="text"],
select {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 1rem;
    color: var(--text-main);
    transition: border-color 0.2s, box-shadow 0.2s;
    background-color: #fff;
    appearance: none;
}

input[type="text"]:focus,
select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* Selector input with suffix */
.selector-wrapper input {
    padding-right: 120px;
}

.selector-suffix {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    font-size: 0.9rem;
    pointer-events: none;
    background: #f8f9fa;
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-md);
}

.select-arrow {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--secondary-color);
    pointer-events: none;
    font-size: 0.8rem;
}

.btn-primary {
    width: 100%;
    padding: 0.875rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
}

.btn-primary:active {
    transform: scale(0.98);
}

.btn-primary:disabled {
    background-color: var(--secondary-color);
    cursor: not-allowed;
    opacity: 0.7;
}

.error-feedback {
    color: var(--error-color);
    font-size: 0.875rem;
    margin-top: 0.25rem;
    display: none;
    animation: fadeIn 0.3s;
}

.input-error input {
    border-color: var(--error-color);
}

.input-error .error-feedback {
    display: block;
}

/* 结果区域样式 */
.hidden {
    display: none !important;
}

.alert {
    padding: 1rem;
    border-radius: var(--radius-md);
    margin-bottom: 1.5rem;
    border-left: 4px solid;
    animation: fadeIn 0.4s;
}

.alert-error {
    background-color: #fef2f2;
    border-color: var(--error-color);
    color: #991b1b;
}

.alert-success {
    background-color: #ecfdf5;
    border-color: var(--success-color);
    color: #065f46;
}

.alert-warning {
    background-color: #fffbeb;
    border-color: var(--warning-color);
    color: #92400e;
}

.result-card h3 {
    font-size: 1.25rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* DKIM记录显示 */
.record-container {
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.95rem;
}

.code-block-wrapper {
    background: #1e293b;
    border-radius: var(--radius-md);
    padding: 1rem;
    position: relative;
    margin-bottom: 0.5rem;
}

#recordOutput {
    color: #e2e8f0;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.9rem;
    word-break: break-all;
    display: block;
    padding-right: 30px;
}

.copy-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background: rgba(255, 255, 255, 0.1);
    border: none;
    color: #fff;
    width: 30px;
    height: 30px;
    border-radius: 4px;
    cursor: pointer;
    transition: background 0.2s;
}

.copy-btn:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* DKIM标签解析 */
.tags-container {
    display: grid;
    gap: 1rem;
}

.tag-item {
    background: #f8fafc;
    border-radius: var(--radius-md);
    padding: 1rem;
    border-left: 3px solid var(--primary-color);
}

.tag-item.tag-warning {
    border-left-color: var(--warning-color);
    background: #fffbeb;
}

.tag-item.tag-error {
    border-left-color: var(--error-color);
    background: #fef2f2;
}

.tag-name {
    font-family: 'Consolas', 'Monaco', monospace;
    font-weight: 600;
    color: var(--primary-color);
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.tag-value {
    font-family: 'Consolas', 'Monaco', monospace;
    color: var(--text-main);
    word-break: break-all;
    margin-bottom: 0.5rem;
    background: white;
    padding: 0.5rem;
    border-radius: var(--radius-md);
}

.tag-description {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* DKIM标签说明 */
.info-card {
    background: #f8fafc;
}

.info-content {
    display: grid;
    gap: 1.25rem;
}

.info-item {
    display: grid;
    grid-template-columns: 60px 1fr;
    gap: 1rem;
    align-items: start;
}

.info-tag {
    font-family: 'Consolas', 'Monaco', monospace;
    font-weight: 600;
    color: var(--primary-color);
    font-size: 1rem;
    background: white;
    padding: 0.5rem;
    border-radius: var(--radius-md);
    text-align: center;
    border: 1px solid var(--border-color);
}

.info-desc {
    font-size: 0.9rem;
    color: var(--text-main);
    line-height: 1.6;
}

.info-desc strong {
    display: block;
    margin-bottom: 0.25rem;
    color: var(--text-main);
}

.info-desc code {
    background: white;
    padding: 0.125rem 0.375rem;
    border-radius: 3px;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.875rem;
    color: var(--primary-color);
    border: 1px solid var(--border-color);
}

.loading-show {
    display: none;
}

/* 动画 */
@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

footer {
    text-align: center;
    color: var(--secondary-color);
    font-size: 0.875rem;
    margin-top: 3rem;
}

/* Captcha Styles */
.captcha-group {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.captcha-img {
    cursor: pointer;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    height: 40px;
    background: #f0f0f0;
    flex-shrink: 0;
    transition: border-color 0.2s;
}

.captcha-img:hover {
    border-color: var(--primary-color);
}

.captcha-group input[type="text"] {
    flex: 0 1 auto;
    min-width: 120px;
    max-width: 180px;
    padding: 0.75rem 1rem;
}

/* Mobile Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 1rem 0.5rem;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .description {
        font-size: 0.9rem;
    }

    .card {
        padding: 1.25rem;
        margin-bottom: 1.5rem;
    }

    .form-group {
        margin-bottom: 1.25rem;
    }

    /* Stack captcha elements on mobile */
    .captcha-group {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .captcha-group input[type="text"] {
        width: 100%;
        max-width: none;
    }

    /* Prevent zoom on iOS when focusing inputs */
    input[type="text"],
    select {
        font-size: 16px;
    }

    .result-card h3 {
        font-size: 1.1rem;
    }

    .info-item {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .info-tag {
        width: fit-content;
    }

    #recordOutput {
        font-size: 0.8rem;
    }
}

/* Extra small devices */
@media (max-width: 480px) {
    header h1 {
        font-size: 1.25rem;
        flex-direction: column;
        gap: 0.5rem;
    }

    .card {
        padding: 1rem;
    }

    .selector-wrapper input {
        padding-right: 100px;
    }

    .selector-suffix {
        font-size: 0.75rem;
        padding: 0.2rem 0.4rem;
    }
}