:root {
    --header-color: #1A3C6E;
    --primary-color: #1D51D2;
    --primary-hover: #163fb0;
    --primary-soft: rgba(29, 81, 210, 0.08);
    --background-color: #f0f2f5;
    --panel-bg: #ffffff;
    --panel-bg-soft: #f7f9fc;
    --panel-bg-hover: #eff3f9;
    --border-color: #cccfd3;
    --border-width: 1px;
    --border-radius: 12px;
    --text-color: #1a2634;
    --secondary-text: #5a6f84;
    --white: #ffffff;
    --footer-bg: #141E2B;
    --footer-text: #a8b9cc;
    --margin: 16px;
    --text-size: 14px;
    --card-shadow: 0 4px 20px rgba(0, 20, 40, 0.06);
    --card-shadow-hover: 0 8px 16px rgba(0, 0, 0, 0.12);
}
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    line-height: 1.5;
}
header {
    background-color: var(--header-color);
    display: flex;
    padding: 16px 24px;
    justify-content: space-between !important;
    align-items: center;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.12);
}
.logo a {
    color: var(--white);
    font-size: 22px;
    font-weight: 600;
    letter-spacing: 0.5px;
    text-decoration: none;
}
.logo a:hover {
    text-decoration: none;
    color: #dce6f5;
}
main {
    flex: 1;
    padding: 16px;
    max-width: 960px;
    margin: 0 auto;
    width: 100%;
}
.content-placeholder {
    width: 100%;
}
.content-box {
    background-color: var(--panel-bg);
    border-radius: var(--border-radius);
    border: var(--border-width) solid var(--border-color);
    box-shadow: var(--card-shadow);
    padding: 28px 32px 24px;
    transition: box-shadow 0.4s ease;
}
.content-box:hover {
    box-shadow: var(--card-shadow-hover);
}
footer {
    background-color: var(--footer-bg);
    color: var(--footer-text);
    text-align: center;
    padding: 20px 16px;
    font-size: 14px;
    line-height: 1.7;
    margin-top: 16px;
}
footer .copyright,
footer .location {
    color: var(--footer-text);
}
footer .location {
    margin-top: 4px;
    font-size: 13px;
    opacity: 0.85;
}
h1 {
    color: var(--text-color);
    font-size: 26px;
    font-weight: 700;
    margin-bottom: 14px;
    letter-spacing: 0.3px;
}
.tool-box .tool-desc {
    color: var(--secondary-text);
    font-size: 16px;
    margin-bottom: var(--margin);
    line-height: 1.6;
}
.tool-box .tool-desc code {
    background-color: var(--panel-bg-soft);
    padding: 2px 6px;
    border-radius: 4px;
    color: var(--primary-color);
    border: 1px solid var(--border-color);
    font-family: 'Courier New', monospace;
    font-size: 0.92em;
}
p {
    color: var(--secondary-text);
    font-size: 16px;
    margin-bottom: var(--margin);
    line-height: 1.6;
}
.tool-subtitle {
    color: var(--primary-color);
    font-size: 22px;
    margin: 16px 0 8px 0;
    text-align: left;
}
.tool-textarea,
textarea.textarea {
    min-height: 180px;
    resize: vertical;
    font-family: 'Courier New', monospace;
    font-size: 14px;
    line-height: 1.6;
    background-color: var(--panel-bg-soft);
    color: var(--text-color);
    border: var(--border-width) solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 10px 12px;
    width: 100%;
    margin-bottom: 12px;
    transition: border-color 0.18s ease, box-shadow 0.18s ease;
}
.tool-textarea:focus,
textarea.textarea:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px var(--primary-soft);
}
.tool-textarea[readonly] {
    background-color: #eef2f8;
    cursor: default;
}
.tool-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
    margin: 16px 0 12px 0;
}
.tool-btn {
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    border-radius: var(--border-radius);
    padding: 8px 22px;
    font-size: var(--text-size);
    font-weight: 500;
    cursor: pointer;
    min-width: 80px;
    font-family: inherit;
    transition: background-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}
.tool-btn:hover {
    background-color: var(--primary-hover);
    box-shadow: 0 4px 12px rgba(29, 81, 210, 0.25);
}
.tool-btn:active {
    transform: translateY(1px);
}
.tool-btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
    box-shadow: none;
}
.tool-stats,
#stats {
    color: var(--secondary-text);
    font-size: 15px;
    margin: 12px 0 16px 0;
    text-align: center;
}
@media (max-width: 800px) {
    header {
        padding: 14px 16px;
    }
    .logo a {
        font-size: 18px;
    }
    main {
        padding: 8px;
    }
    .content-box {
        padding: 20px 16px;
    }
    h1 {
        font-size: 22px;
    }
    .tool-subtitle {
        font-size: 18px;
    }
    .tool-actions {
        gap: 8px;
    }
    .tool-btn {
        padding: 8px 16px;
        font-size: 13px;
    }
}