:root {
    --clr-bg-light: white;
    --clr-bg-dark: #1e1e2f;
    --clr-text-light: #2d3436;
    --clr-text-dark: #dfe6e9;
    --clr-primary-start: #6c5ce7;
    --clr-primary-end: #341f97;
    --clr-input-border-light: #dcdde1;
    --clr-input-border-dark: #555770;
    --clr-msg-bg-light: #ffeaa7;
    --clr-msg-bg-dark: #f39c12;
    --transition-speed: 0.3s;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #6c5ce7, #00b894);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    color: var(--clr-text-light);
    transition: background var(--transition-speed), color var(--transition-speed);
    overflow: hidden;
}

body.dark {
    background: #12122e;
    color: var(--clr-text-dark);
}

.form-container {
    background: var(--clr-bg-light);
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
    width: 400px;
    max-width: 90vw;
    transition: background var(--transition-speed), box-shadow var(--transition-speed), color var(--transition-speed), transform 0.6s ease;
    animation: fadeSlideIn 0.8s ease forwards;
}

body.dark .form-container {
    background: var(--clr-bg-dark);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.8);
    color: var(--clr-text-dark);
}

.form-container:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.2);
}

.form-container h2 {
    text-align: center;
    margin-bottom: 25px;
    font-size: 26px;
    font-weight: 700;
}

.form-container label {
    display: block;
    margin: 12px 0 6px;
    font-weight: 600;
}

.form-container input {
    width: 100%;
    padding: 12px;
    border: 1.5px solid var(--clr-input-border-light);
    border-radius: 8px;
    outline: none;
    transition: border-color var(--transition-speed), box-shadow var(--transition-speed), background var(--transition-speed), color var(--transition-speed);
    font-size: 15px;
    background: white;
    color: var(--clr-text-light);
}

body.dark .form-container input {
    background: #2c2c4a;
    color: var(--clr-text-dark);
    border-color: var(--clr-input-border-dark);
}

.form-container input:focus {
    border-color: var(--clr-primary-start);
    box-shadow: 0 0 8px rgba(108, 92, 231, 0.7);
}

.form-container button {
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, var(--clr-primary-start), var(--clr-primary-end));
    color: white;
    border: none;
    border-radius: 8px;
    margin-top: 20px;
    cursor: pointer;
    transition: background var(--transition-speed), transform 0.2s;
    font-size: 16px;
    font-weight: 700;
}

.form-container button:hover {
    background: linear-gradient(135deg, #5a4dcf, #2c1b7f);
    transform: translateY(-2px);
}

/* Message notification */
.message {
    position: fixed;
    top: 20px;
    left: 50%;
    transform: translateX(-50%) translateY(-100%);
    background: var(--clr-msg-bg-light);
    color: #2d3436;
    padding: 14px 30px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.15);
    font-weight: 600;
    font-size: 16px;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.4s, transform 0.4s;
    z-index: 9999;
}

.message.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
    pointer-events: auto;
}

body.dark .message {
    background: var(--clr-msg-bg-dark);
    color: white;
}

/* Dark mode toggle button */
.toggle-theme {
    position: fixed;
    top: 15px;
    right: 15px;
    background: transparent;
    border: 2px solid var(--clr-msg-bg-light);
    color: var(--clr-msg-bg-light);
    padding: 8px 14px;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 600;
    font-size: 14px;
    transition: background var(--transition-speed), color var(--transition-speed), border-color var(--transition-speed);
    z-index: 10000;
}

body.dark .toggle-theme {
    border-color: var(--clr-msg-bg-dark);
    color: var(--clr-msg-bg-dark);
}

.toggle-theme:hover {
    background: var(--clr-msg-bg-light);
    color: var(--clr-text-light);
}

body.dark .toggle-theme:hover {
    background: var(--clr-msg-bg-dark);
    color: white;
}

/* Animations */
@keyframes fadeSlideIn {
    0% {
        opacity: 0;
        transform: translateY(40px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 450px) {
    .form-container {
        width: 90%;
        padding: 20px;
    }
}