/* === LOGIN PAGE - Cloud Design with Overlay Form === */

/* Login-specific Dark Mode tokens
   Dùng html.dark class (toggle bằng JS) thay vì prefers-color-scheme
   để user có thể tự chọn theme */
:root {
    --login-bg: #f1f5f9;
    --login-gradient:
        radial-gradient(at 0% 0%, rgba(59, 130, 246, 0.3) 0, transparent 50%),
        radial-gradient(at 80% 0%, rgba(147, 51, 234, 0.3) 0, transparent 50%),
        radial-gradient(at 50% 100%, rgba(236, 72, 153, 0.2) 0, transparent 50%);
    --login-text: #334155;
    --login-text-secondary: #64748b;
    --login-text-placeholder: #94a3b8;
    --login-border-color: rgba(0, 0, 0, 0.1);
    --login-border-focus: #3b82f6;
    --login-btn-bg: #3b5998;
    --login-btn-hover: #2d4373;
    --login-error-bg: #fef2f2;
    --login-error-text: #dc2626;
    --login-input-bg: rgba(255, 255, 255, 0.95);
    --login-toggle-bg: rgba(255, 255, 255, 0.9);
    --login-toggle-dark-bg: rgba(30, 41, 59, 0.9);
    /* Input text luôn tối vì input-bg luôn sáng (rgba white) */
    --login-input-color: #1e293b;
}

html.dark {
    --login-bg: #0f172a;
    --login-gradient:
        radial-gradient(at 0% 0%, rgba(30, 41, 59, 1) 0, transparent 50%),
        radial-gradient(at 50% 0%, rgba(59, 130, 246, 0.4) 0, transparent 50%),
        radial-gradient(at 100% 0%, rgba(147, 51, 234, 0.3) 0, transparent 50%);
    --login-text: #f1f5f9;
    --login-text-secondary: #94a3b8;
    --login-text-placeholder: #64748b;
    --login-border-color: rgba(255, 255, 255, 0.15);
    --login-border-focus: #60a5fa;
    --login-btn-bg: #4a72b8;
    --login-btn-hover: #3b5998;
    --login-error-bg: rgba(127, 29, 29, 0.4);
    --login-error-text: #fca5a5;
    --login-input-bg: rgba(30, 41, 59, 0.9);
    /* Input bg vẫn là white-transparent nên text phải tối */
    --login-input-color: #1e293b;
}

/* Body Override for Login Page */
body.login-page {
    background-color: var(--login-bg);
    background-image: var(--login-gradient);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: var(--space-xl);
    transition: background var(--transition-slow);
    overflow: visible;
    margin: 0;
}

/* Login Container */
.login-container {
    width: 100%;
    max-width: 700px;
    animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* Cloud Card with PNG Background */
.login-card {
    position: relative;
    width: 100%;
    aspect-ratio: 641 / 408;
    display: flex;
    justify-content: center;
    align-items: center;
}

.login-card-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: contain;
    z-index: 1;
    filter: drop-shadow(0 25px 50px rgba(0, 0, 0, 0.15));
}

html.dark .login-card-bg {
    filter: drop-shadow(0 25px 50px rgba(0, 0, 0, 0.4)) brightness(0.85);
}

/* Form Overlay - Transparent form on top of cloud image */
.login-form-overlay {
    position: relative;
    z-index: 10;
    width: 55%;
    max-width: 260px;
    padding: var(--space-xl) 25px;
    margin-top: 100px;
    margin-left: 18px;
}

/* Form Styles */
.login-form-overlay form {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.login-form-overlay .form-group {
    margin: 0;
}

.login-form-overlay .form-group input {
    width: 100%;
    box-sizing: border-box;
    padding: var(--space-md) var(--space-lg);
    background: rgba(255, 255, 255, 0.3);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    border: 1px solid rgba(255, 255, 255, 0.5);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    color: var(--login-input-color);
    transition: var(--transition-normal);
    outline: none;
}

/* Username: in đậm + cỡ chữ lớn hơn */
#username {
    font-weight: 700;
    font-size: var(--font-size-xl);
    /* 18px */
    letter-spacing: 0.01em;
}

#username::placeholder {
    font-weight: 400;
    font-size: var(--font-size-base);
    letter-spacing: normal;
}

.login-form-overlay .form-group input::placeholder {
    color: var(--login-text-placeholder);
}

.login-form-overlay .form-group input:focus {
    border-color: var(--login-border-focus);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

/* Password Input Wrapper */
.password-input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.password-input-wrapper input {
    padding-right: 40px;
}

.password-toggle {
    position: absolute;
    right: 10px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: var(--space-xs);
    color: var(--login-text-secondary);
    transition: color var(--transition-fast);
}

.password-toggle:hover {
    color: var(--login-text);
}

.password-toggle svg {
    width: 18px;
    height: 18px;
}

/* Password Group Animation */
.password-group {
    opacity: 0;
    max-height: 0;
    overflow: hidden;
    transition: opacity var(--transition-normal), max-height var(--transition-normal);
}

.password-group.show {
    opacity: 1;
    max-height: 100px;
}

/* Login Button with Animated Gradient */
@keyframes gradientFlow {
    0% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0% 50%;
    }
}

.btn-login {
    width: 100%;
    padding: var(--space-md);
    background: linear-gradient(90deg,
            rgba(59, 130, 246, 0.6),
            rgba(147, 51, 234, 0.6),
            rgba(236, 72, 153, 0.6),
            rgba(147, 51, 234, 0.6),
            rgba(59, 130, 246, 0.6));
    background-size: 300% 100%;
    animation: gradientFlow 4s ease infinite;
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    color: var(--color-surface);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-normal);
    margin-top: var(--space-xs);
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

html.dark .btn-login {
    background: linear-gradient(90deg,
            rgba(59, 130, 246, 0.7),
            rgba(147, 51, 234, 0.7),
            rgba(96, 165, 250, 0.7),
            rgba(147, 51, 234, 0.7),
            rgba(59, 130, 246, 0.7));
    background-size: 300% 100%;
    animation: gradientFlow 4s ease infinite;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-login:hover {
    background-size: 400% 100%;
    animation-duration: 2s;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

/* Form Links */
.form-links {
    text-align: center;
    margin-top: 10px;
}

.forgot-password {
    color: var(--login-text-secondary);
    font-size: var(--font-size-xs);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.forgot-password:hover {
    color: var(--login-text);
    text-decoration: underline;
}

.signup-link {
    margin-top: var(--space-xs);
    font-size: var(--font-size-xs);
    color: var(--login-text-secondary);
}

.signup-link a {
    color: var(--login-btn-bg);
    font-weight: 600;
    text-decoration: none;
}

.signup-link a:hover {
    text-decoration: underline;
}

/* Error Message */
.error-message {
    background: var(--login-error-bg);
    color: var(--login-error-text);
    padding: 10px 14px;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-sm);
    margin-top: 10px;
    text-align: center;
    border: 1px solid rgba(220, 38, 38, 0.2);
}

/* Theme Toggle Button */
.theme-toggle {
    position: fixed;
    bottom: var(--space-2xl);
    right: var(--space-2xl);
    width: 48px;
    height: 48px;
    background: var(--login-toggle-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--login-border-color);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    transition: var(--transition-normal);
    z-index: var(--z-modal);
}

html.dark .theme-toggle {
    background: var(--login-toggle-dark-bg);
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
}

.theme-toggle svg {
    width: 22px;
    height: 22px;
    color: var(--login-text);
    transition: var(--transition-normal);
}

/* Sun icon visible in dark mode, hidden in light */
.theme-toggle .icon-sun {
    display: none;
}

html.dark .theme-toggle .icon-sun {
    display: block;
}

html.dark .theme-toggle .icon-moon {
    display: none;
}

/* Responsive */
@media (max-width: 600px) {
    .login-container {
        max-width: 95%;
    }

    .login-form-overlay {
        width: 60%;
        max-width: 200px;
        padding: 15px var(--space-xl);
    }

    .login-form-overlay .form-group input {
        padding: 10px 14px;
        font-size: var(--font-size-sm);
    }

    .btn-login {
        padding: 10px;
        font-size: var(--font-size-sm);
    }

    .theme-toggle {
        bottom: var(--space-lg);
        right: var(--space-lg);
        width: 42px;
        height: 42px;
    }
}