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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    position: relative;
    overflow: hidden;
}

/* 動画背景 */
.video-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -2;
    overflow: hidden;
}

.video-background video {
    position: absolute;
    top: 50%;
    left: 50%;
    min-width: 100%;
    min-height: 100%;
    width: auto;
    height: auto;
    transform: translate(-50%, -50%);
    object-fit: cover;
}

/* 動画の上にオーバーレイを追加して視認性を向上 */
.video-background::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(102, 126, 234, 0.4);
    z-index: -1;
}

.auth-container {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    width: 100%;
    max-width: 440px;
    padding: 48px 40px;
    animation: fadeIn 0.5s ease-in;
    position: relative;
    z-index: 1;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.auth-header {
    text-align: center;
    margin-bottom: 36px;
}

.auth-header h1 {
    color: #1a202c;
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
}

.auth-header p {
    color: #718096;
    font-size: 14px;
}

.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    color: #2d3748;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 8px;
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 14px;
    transition: all 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.btn-primary {
    width: 100%;
    padding: 14px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 8px;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.divider {
    display: flex;
    align-items: center;
    margin: 32px 0;
    color: #a0aec0;
    font-size: 14px;
}

.divider::before,
.divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: #e2e8f0;
}

.divider::before {
    margin-right: 16px;
}

.divider::after {
    margin-left: 16px;
}

.btn-google {
    width: 100%;
    padding: 12px;
    background: white;
    color: #4a5568;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    transition: all 0.3s ease;
}

.btn-google:hover {
    background: #f7fafc;
    border-color: #cbd5e0;
}

.auth-footer {
    text-align: center;
    margin-top: 32px;
    color: #718096;
    font-size: 14px;
}

.auth-footer a {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s ease;
}

.auth-footer a:hover {
    color: #764ba2;
}

.alert {
    padding: 12px 16px;
    border-radius: 8px;
    margin-bottom: 24px;
    font-size: 14px;
}

.alert-error {
    background: #fed7d7;
    color: #c53030;
    border: 1px solid #fc8181;
}

.alert-success {
    background: #c6f6d5;
    color: #2f855a;
    border: 1px solid #9ae6b4;
}

.loading {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.6s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}