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

body {
    margin: 0;
    padding: 20px;
    padding-top: 80px;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(to bottom, #000428 0%, #004e92 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

/* ヘッダースタイル */
.main-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding: 12px 0;
    z-index: 1000;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.header-link {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 0 20px;
    font-weight: 600;
    color: white;
    text-decoration: none;
    font-size: 1.1rem;
    transition: color 0.3s ease;
}

.header-link:hover {
    color: #60a5fa;
}

.header-logo {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid rgba(255, 255, 255, 0.2);
}

.container {
    background: rgba(10, 10, 30, 0.85);
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.5), 0 0 100px rgba(100, 150, 255, 0.2);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    padding: 40px;
    max-width: 700px;
    width: 100%;
}

h1 {
    text-align: center;
    color: #ffffff;
    margin-bottom: 10px;
    font-size: 28px;
    text-shadow: 0 0 20px rgba(255, 255, 255, 0.5), 0 0 40px rgba(100, 150, 255, 0.3);
}

.subtitle {
    text-align: center;
    color: #b8c5db;
    margin-bottom: 30px;
    font-size: 0.9em;
}

.input-group {
    margin-bottom: 25px;
}

label {
    display: block;
    margin-bottom: 8px;
    color: #b8c5db;
    font-weight: 600;
    font-size: 14px;
}

input[type="text"],
input[type="url"],
textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    font-size: 16px;
    transition: border-color 0.3s, box-shadow 0.3s;
    font-family: inherit;
    background: rgba(20, 20, 50, 0.5);
    color: #ffffff;
}

input[type="text"]:focus,
input[type="url"]:focus,
textarea:focus {
    outline: none;
    border-color: #26d0ce;
    box-shadow: 0 0 15px rgba(38, 208, 206, 0.3);
}

textarea {
    resize: vertical;
    min-height: 80px;
}

.size-control {
    display: flex;
    align-items: center;
    gap: 15px;
}

input[type="range"] {
    flex: 1;
    height: 6px;
    border-radius: 3px;
    background: #e0e0e0;
    outline: none;
    -webkit-appearance: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #26d0ce;
    cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #26d0ce;
    cursor: pointer;
    border: none;
}

.size-value {
    font-weight: 600;
    color: #26d0ce;
    min-width: 60px;
    text-align: right;
    text-shadow: 0 0 10px rgba(38, 208, 206, 0.5);
}

.color-control {
    display: flex;
    gap: 20px;
}

.color-item {
    flex: 1;
}

input[type="color"] {
    width: 100%;
    height: 50px;
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    cursor: pointer;
    background: rgba(20, 20, 50, 0.5);
}

button {
    width: 100%;
    padding: 15px;
    background: linear-gradient(135deg, #1a2980 0%, #26d0ce 100%);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    margin-top: 10px;
    box-shadow: 0 4px 15px rgba(38, 208, 206, 0.3);
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(38, 208, 206, 0.5), 0 0 30px rgba(38, 208, 206, 0.3);
}

button:active {
    transform: translateY(0);
}

#qrcode {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 30px 0;
    min-height: 200px;
    background: rgba(20, 20, 50, 0.5);
    border-radius: 10px;
    padding: 20px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

#qrcode canvas,
#qrcode img {
    border-radius: 10px;
}

.download-btn {
    background: linear-gradient(135deg, #1a2980 0%, #26d0ce 100%);
    display: none;
}

.download-btn:hover {
    box-shadow: 0 6px 20px rgba(38, 208, 206, 0.5), 0 0 30px rgba(38, 208, 206, 0.3);
}

#gif-btn {
    background: linear-gradient(135deg, #1a2980 0%, #26d0ce 100%);
    color: white;
}

#gif-btn:hover {
    box-shadow: 0 6px 20px rgba(38, 208, 206, 0.5), 0 0 30px rgba(38, 208, 206, 0.3);
}

.tab-buttons {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.tab-btn {
    flex: 1;
    padding: 10px;
    background: rgba(20, 20, 50, 0.5);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
    color: #b8c5db;
}

.tab-btn.active {
    background: linear-gradient(135deg, #1a2980 0%, #26d0ce 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(38, 208, 206, 0.3);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.info {
    background: rgba(20, 20, 50, 0.5);
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 20px;
    color: #b8c5db;
    font-size: 14px;
    line-height: 1.6;
    border: 1px solid rgba(255, 255, 255, 0.1);
}