:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
    --card-bg: rgba(255, 255, 255, 0.05);
    --card-border: rgba(255, 255, 255, 0.1);
    --card-hover: rgba(255, 255, 255, 0.08);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #10b981;
    --glass-blur: 12px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background: var(--bg-gradient);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

/* Header */
header {
    padding: 2rem;
    text-align: center;
    border-bottom: 1px solid var(--card-border);
    backdrop-filter: blur(var(--glass-blur));
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.05em;
    background: linear-gradient(to right, #818cf8, #34d399);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

/* Main Layout */
main {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    width: 100%;
}

.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.tool-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 1rem;
    padding: 2rem;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(var(--glass-blur));
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.tool-card:hover {
    background: var(--card-hover);
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: 0 10px 30px -10px rgba(99, 102, 241, 0.3);
}

.tool-card h2 {
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.tool-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

.icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(99, 102, 241, 0.1);
    border-radius: 0.75rem;
    color: var(--primary-color);
}

/* Active Tool Container */
.tool-display {
    margin-top: 3rem;
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 1.5rem;
    padding: 3rem;
    backdrop-filter: blur(var(--glass-blur));
    display: none;
    /* 初期は非表示 */
}

.tool-display.active {
    display: block;
    animation: fadeIn 0.5s ease-out;
}

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

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

/* Tool UI Elements */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

input,
select,
textarea {
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--card-border);
    border-radius: 0.5rem;
    padding: 0.75rem 1rem;
    color: white;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
    width: 100%;
}

textarea {
    resize: none;
    min-height: 80px;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    font-size: 1rem;
    line-height: 1.5;
    letter-spacing: 0;
    overflow: hidden;
    overflow-wrap: break-word;
    word-break: break-word;
}

select option {
    background: #1e1b4b;
    color: white;
}

input:focus,
select:focus,
textarea:focus {
    border-color: var(--primary-color);
}

/* contenteditable入力エリア */
.editable-container {
    position: relative;
}

.editable-input {
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--card-border);
    border-radius: 0.5rem;
    padding: 0.75rem 1rem;
    color: white;
    font-size: 1rem;
    line-height: 1.5;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    min-height: 80px;
    outline: none;
    transition: border-color 0.2s;
    width: 100%;
    box-sizing: border-box;
    white-space: pre-wrap;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.editable-input:focus {
    border-color: var(--primary-color);
}

.editable-input:empty::before {
    content: attr(data-placeholder);
    color: rgba(255, 255, 255, 0.4);
    pointer-events: none;
}

.editable-input.warning {
    border-color: #fbbf24;
}

.editable-input.over-limit {
    border-color: #f87171;
}

/* 超過文字のハイライト */
.editable-input .excess-char {
    background-color: rgba(239, 68, 68, 0.5);
    border-radius: 2px;
}

.error-msg {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.2);
    color: #fca5a5;
    padding: 1rem;
    border-radius: 0.5rem;
    margin-top: 1rem;
    font-size: 0.9rem;
    text-align: center;
}

.char-counter {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
    text-align: right;
}

.char-counter.warning {
    color: #fbbf24;
}

.char-counter.error {
    color: #f87171;
}

.download-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn-secondary {
    background: transparent;
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
}

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

.btn {
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

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

/* Viewport Info Style */
#viewport-info {
    text-align: center;
}

.pixel-value {
    font-size: 4rem;
    font-weight: 800;
    color: var(--accent-color);
    margin: 1rem 0;
}

.info-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-top: 2rem;
}

.info-item {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--card-border);
    border-radius: 0.75rem;
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.info-item.full-width {
    grid-column: 1 / -1;
    margin-top: 1.5rem;
}

.info-item .label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.info-item .value {
    font-size: 1.25rem;
    font-weight: 600;
}

.ua-container {
    background: rgba(0, 0, 0, 0.3);
    padding: 1rem;
    border-radius: 0.5rem;
    word-break: break-all;
    font-family: monospace;
    font-size: 0.9rem;
    color: var(--text-secondary);
    text-align: left;
    margin-top: 0.5rem;
}

/* QR Code Style */
#qrcode-display {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
    margin-top: 2rem;
}

#qr-canvas {
    background: white;
    padding: 1rem;
    border-radius: 0.5rem;
    max-width: 100%;
}

footer {
    padding: 2rem;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Responsive Adjustments */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.75rem;
    }

    main {
        padding: 1rem;
    }

    .tool-grid {
        grid-template-columns: 1fr;
    }

    .tool-display {
        padding: 1.5rem;
    }

    .pixel-value {
        font-size: 2.5rem;
    }

    .info-grid {
        grid-template-columns: 1fr;
    }
}