:root {
    color-scheme: light dark;
    --bg: #f8fafc;
    --card: #ffffff;
    --border: #e2e8f0;
    --text: #0f172a;
    --muted: #64748b;
    --accent: #2563eb;
    --accent-dark: #1d4ed8;
    --shadow: 0 20px 45px rgba(15, 23, 42, 0.08);
    font-size: 16px;
}

* {
    box-sizing: border-box;
}

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
    margin: 0;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

img {
    max-width: 100%;
}

a {
    color: inherit;
}

main {
    padding: 2.5rem clamp(1rem, 4vw, 3rem) 4rem;
}

.hero {
    background: radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.25), transparent 55%),
        radial-gradient(circle at 90% 10%, rgba(14, 165, 233, 0.25), transparent 50%),
        #0f172a;
    color: #e2e8f0;
    padding: clamp(2.5rem, 8vw, 6rem) clamp(1rem, 5vw, 4rem);
}

.hero__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2.5rem;
    align-items: center;
}

.hero__label {
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-size: 0.85rem;
    color: rgba(226, 232, 240, 0.8);
}

.hero h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
    margin: 0.5rem 0 1rem;
}

.hero__lead {
    font-size: 1.05rem;
    color: rgba(226, 232, 240, 0.9);
}

.hero__actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin: 1.5rem 0 1rem;
}

.hero__meta {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    padding: 0;
    margin: 0;
    font-size: 0.9rem;
    color: rgba(226, 232, 240, 0.75);
}

.hero__card {
    background: rgba(15, 23, 42, 0.4);
    border: 1px solid rgba(226, 232, 240, 0.2);
    border-radius: 1.25rem;
    padding: 2rem;
    box-shadow: 0 20px 40px rgba(15, 23, 42, 0.35);
}

.hero__card-label {
    font-size: 0.85rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: rgba(226, 232, 240, 0.6);
    margin: 0 0 1rem;
}

.hero__card-preview {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.preview-pill {
    background: rgba(226, 232, 240, 0.15);
    border-radius: 999px;
    padding: 0.35rem 0.9rem;
    font-size: 0.8rem;
}

.tool {
    background: var(--card);
    border-radius: 1.5rem;
    box-shadow: var(--shadow);
    display: grid;
    grid-template-columns: 1.2fr minmax(320px, 0.85fr);
    gap: 2rem;
    padding: clamp(1.5rem, 3vw, 2.5rem);
    margin-top: -3rem;
    border: 1px solid var(--border);
}

.tool__preview {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

.eyebrow {
    text-transform: uppercase;
    font-size: 0.8rem;
    letter-spacing: 0.08em;
    color: var(--muted);
    margin: 0 0 0.25rem;
}

.muted {
    color: var(--muted);
    margin: 0;
}

.preview-actions {
    display: flex;
    gap: 0.5rem;
}

.canvas-wrap {
    background: linear-gradient(180deg, #e2e8f0 0%, #f8fafc 100%);
    border-radius: 1.25rem;
    padding: 1rem;
    border: 1px solid var(--border);
}

canvas {
    width: 100%;
    display: block;
    border-radius: 1rem;
    background: #fff;
}

.preview-info {
    font-size: 0.9rem;
    color: var(--muted);
}

.tool__controls {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.control-form fieldset {
    border: 1px solid var(--border);
    border-radius: 1rem;
    padding: 1rem;
    margin: 0 0 1rem;
}

.control-form legend {
    font-weight: 600;
    padding: 0 0.25rem;
}

label {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    font-size: 0.95rem;
    margin-bottom: 0.75rem;
}

input[type="text"],
select {
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    padding: 0.7rem 0.9rem;
    font-size: 0.95rem;
    font-family: inherit;
    background: #fff;
}

input[type="range"] {
    width: 100%;
}

input[type="color"] {
    padding: 0;
    border-radius: 0.5rem;
    height: 2.5rem;
    border: none;
    background: transparent;
}

.switch-label {
    flex-direction: row;
    align-items: center;
    gap: 0.5rem;
}

.btn {
    border: none;
    border-radius: 999px;
    padding: 0.65rem 1.4rem;
    font-size: 0.95rem;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.35rem;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

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

.btn--primary {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 10px 20px rgba(37, 99, 235, 0.2);
}

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

.btn--ghost {
    border: 1px solid rgba(255, 255, 255, 0.5);
    color: inherit;
    background: transparent;
}

.btn--subtle {
    border: 1px solid var(--border);
    background: #f1f5f9;
    color: var(--text);
}

.inline-actions {
    display: flex;
    gap: 0.5rem;
}

.icon-picker {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.icon-picker button {
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    padding: 0.6rem;
    background: #fff;
    cursor: pointer;
    font-size: 0.85rem;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 0.25rem;
    color: var(--muted);
}

.icon-picker button.is-active {
    border-color: var(--accent);
    color: var(--accent);
    box-shadow: 0 10px 20px rgba(37, 99, 235, 0.15);
}

.color-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 0.75rem;
}

.insight-card {
    border: 1px dashed var(--border);
    border-radius: 1rem;
    padding: 1rem;
    background: #f8fafc;
}

.insight-card ul {
    margin: 0;
    padding-left: 1.2rem;
    color: var(--muted);
}

.feature-grid {
    margin: 4rem 0 3rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
}

.feature-grid article {
    background: #fff;
    border-radius: 1rem;
    padding: 1.5rem;
    border: 1px solid var(--border);
}

.seo-text {
    background: #0f172a;
    color: #e2e8f0;
    border-radius: 1.5rem;
    padding: clamp(1.5rem, 4vw, 3rem);
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
}

.seo-text ul {
    margin: 0;
    padding-left: 1.2rem;
}

.faq {
    margin-top: 3rem;
}

.faq details {
    background: #fff;
    border-radius: 1rem;
    border: 1px solid var(--border);
    padding: 1rem 1.25rem;
    margin-bottom: 1rem;
}

.site-footer {
    text-align: center;
    padding: 2rem 1rem 3rem;
    font-size: 0.9rem;
    color: var(--muted);
}

@media (max-width: 960px) {
    .tool {
        grid-template-columns: 1fr;
        margin-top: 1rem;
    }

    .preview-actions {
        width: 100%;
        justify-content: flex-start;
    }
}

@media (max-width: 600px) {
    .hero__actions {
        flex-direction: column;
        align-items: stretch;
    }

    .inline-actions {
        flex-direction: column;
    }
}