/* Reset and Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px; /* Base font size for rem units */
}

body {
    font-family: 'Inter', 'Noto Sans JP', sans-serif;
    color: #e0e0e0; /* Light grey for general text, good contrast on dark greens */
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden; /* Prevents scrollbars from gradient overflow */
    /* Flowing Gradient Background - Using deep, elegant Japanese-inspired greens */
    background: linear-gradient(-45deg, #00402E, #1A3A3A, #2A5242, #3C6A47);
    background-size: 400% 400%;
    animation: gradientFlow 20s ease infinite;
}

@keyframes gradientFlow {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* Login Page Container */
.login-container {
    width: 100%;
    max-width: 450px; /* Max width for the form */
    padding: 2rem; /* Responsive padding */
    margin: 1rem; /* Margin for smaller screens */
    text-align: center;
}

/* Header Styling */
.login-header {
    margin-bottom: 2rem;
}

.login-header h1 {
    font-family: 'Shippori Mincho', serif;
    font-size: 1.8rem; /* Responsive font size */
    font-weight: 800; /* 重厚感を出すためにウェイトを700から800に変更 */
    color: #f5f5f5; /* Slightly brighter for title */
    margin-bottom: 0.5rem;
    text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.3); /* Subtle shadow for depth */
}

.login-header p {
    font-size: 1rem;
    color: #c0c0c0; /* Softer color for subtitle */
    font-weight: 400;
}

/* Form Container Styling */
.login-form-wrapper {
    background: rgba(10, 25, 20, 0.6); /* Dark, semi-transparent green tint */
    padding: 2.5rem 2rem; /* More padding inside the form */
    border-radius: 12px; /* Softer, more rounded corners */
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37),
                inset 0 0 10px rgba(0,0,0,0.2); /* Outer and subtle inner shadow */
    backdrop-filter: blur(8px); /* Frosted glass effect */
    -webkit-backdrop-filter: blur(8px); /* For Safari */
    border: 1px solid rgba(200, 220, 210, 0.18); /* Subtle border */
}

/* Form Group Styling */
.form-group {
    margin-bottom: 1.5rem;
    text-align: left; /* Align labels and inputs to the left */
}

.form-group label {
    display: block;
    font-size: 0.9rem;
    color: #b0c0b8; /* Muted green-ish white for labels */
    margin-bottom: 0.5rem;
    font-weight: 700; /* ラベルのウェイトを600から700に変更 */
}

.form-group input[type="email"],
.form-group input[type="password"] {
    width: 100%;
    padding: 0.9rem 1rem;
    border: 1px solid rgba(200, 220, 210, 0.25); /* Subtle border */
    border-radius: 8px; /* Consistent rounded corners */
    background-color: rgba(0, 0, 0, 0.25); /* Darker transparent background for inputs */
    color: #f0f0f0; /* Light text color for input */
    font-size: 1rem;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.form-group input[type="email"]::placeholder,
.form-group input[type="password"]::placeholder {
    color: #90a098; /* Muted placeholder text */
}

.form-group input[type="email"]:focus,
.form-group input[type="password"]:focus {
    outline: none;
    border-color: rgba(120, 180, 150, 0.7); /* Shibui green focus highlight */
    box-shadow: 0 0 0 3px rgba(100, 160, 130, 0.3); /* Soft glow on focus */
}

/* Submit Button Styling */
.submit-btn {
    width: 100%;
    padding: 0.9rem 1rem;
    background-color: #3A8B76; /* A shibui, yet distinct green for the button */
    color: #ffffff;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600; /* ボタンテキストのウェイトは維持 */
    font-family: 'Inter', sans-serif;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.submit-btn:hover {
    background-color: #4A9C86; /* Slightly lighter on hover */
    transform: translateY(-2px); /* Subtle lift effect */
}

.submit-btn:active {
    background-color: #2A7A66; /* Darker on click */
    transform: translateY(0);
}

/* Footer Styling */
.login-footer {
    margin-top: 2.5rem;
    font-size: 0.85rem;
    color: #a0b0a8; /* Muted color for footer */
}

/* Error Message Styling */
.error-message {
    color: #ffdddd; /* Light red for errors */
    background-color: #850000; /* Dark red background */
    padding: 0.8rem 1.2rem;
    border-radius: 8px;
    margin-top: 1rem;
    display: none; /* Hidden by default */
    font-size: 0.9rem;
    text-align: center;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .login-header h1 {
        font-size: 1.6rem;
    }
    .login-header p {
        font-size: 0.9rem;
    }
    .login-form-wrapper {
        padding: 2rem 1.5rem;
    }
}

@media (max-width: 480px) {
    html {
        font-size: 15px; /* Slightly smaller base for very small screens */
    }
    .login-container {
        padding: 1.5rem 1rem;
    }
    .login-header h1 {
        font-size: 1.4rem;
    }
    .login-header p {
        font-size: 0.85rem;
    }
    .login-form-wrapper {
        padding: 1.5rem 1rem;
    }
    .form-group input[type="email"],
    .form-group input[type="password"],
    .submit-btn {
        padding: 0.8rem;
        font-size: 0.95rem;
    }
    .submit-btn {
        font-size: 1rem;
    }
}