:root {
    --primary-color: #2c3e50;
    --bg-color: #f5f6fa;
    --text-color: #2d3436;
    --box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    --input-bg: #ffffff;
    --box-bg: rgba(255, 255, 255, 0.9);
}

.dark-theme {
    --primary-color: #000000;
    --bg-color: #000000;
    --text-color: #ffffff;
    --box-shadow: 0 5px 25px rgba(0, 0, 0, 0.5);
    --input-bg: #111111;
    --box-bg: #0a0a0a;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Arial', sans-serif;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: var(--bg-color);
    transition: 0.5s;
}

.theme-switch {
    position: fixed;
    top: 20px;
    right: 20px;
    cursor: pointer;
    z-index: 100;
}

.theme-switch i {
    font-size: 24px;
    color: var(--text-color);
    transition: 0.5s;
    filter: drop-shadow(0 0 5px var(--text-color));
}

.dark-theme .theme-switch i {
    color: var(--primary-color);
    filter: drop-shadow(0 0 5px var(--primary-color));
}

.dark-theme .theme-switch i.fa-sun {
    color: #ffffff;
}

.dark-theme .theme-switch i.fa-moon {
    color: #ffffff;
}

.login-container {
    position: relative;
    width: 400px;
    padding: 40px;
}

.login-box {
    background: var(--box-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: var(--box-shadow);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.dark-theme .login-box {
    border: 1px solid #222;
    background: var(--box-bg);
}

h2 {
    color: var(--text-color);
    text-align: center;
    margin-bottom: 30px;
    font-size: 2em;
}

.input-box {
    position: relative;
    margin-bottom: 20px;
    height: 50px;
}

.input-box input {
    width: 100%;
    height: 100%;
    padding: 0 40px 0 15px;
    border: 1px solid #333;
    border-radius: 5px;
    background: var(--input-bg);
    color: var(--text-color);
    font-size: 16px;
    outline: none;
}

.input-box input::placeholder {
    color: #777;
}

.dark-theme .input-box input::placeholder {
    color: #666;
}

.input-box i {
    position: absolute;
    right: 15px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-color);
}

.remember-forgot {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
    color: var(--text-color);
}

button {
    width: 100%;
    padding: 12px;
    background: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 5px;
    margin-bottom:20px;
    cursor: pointer;
    font-size: 16px;
}

.dark-theme button {
    background: #000000;
    color: #ffffff;
    border: 1px solid #333;
}

button:hover {
    background: #111111;
}

.register-link {
    text-align: center;
    margin-top: 20px;
    color: var(--text-color);
}

.register-link a {
    color: var(--text-color);
    text-decoration: none;
}

.dark-theme .register-link a,
.dark-theme .remember-forgot a {
    color: #ffffff;
}

.dark-theme .register-link a:hover,
.dark-theme .remember-forgot a:hover {
    color: #cccccc;
}

.login-box {
    background: var(--box-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: var(--box-shadow);
}


/* Dark mode */
.dark-theme .error-message-login {
    background-color: rgba(255, 0, 0, 0.15);
    color: #ff4444;
}

/* Animazione di comparsa */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}


/* 4K Displays */
@media screen and (max-width: 2560px) {
    .login-container {
        width: 600px;
    }
    
    h2 {
        font-size: 2.5em;
    }
    
    .input-box input {
        font-size: 18px;
    }
}

/* Large Desktop Screens */
@media screen and (max-width: 1920px) {
    .login-container {
        width: 500px;
    }
    
    h2 {
        font-size: 2.2em;
    }
}

/* Standard Desktop */
@media screen and (max-width: 1440px) {
    .login-container {
        width: 450px;
    }
    
    h2 {
        font-size: 2em;
    }
}

/* Small Desktop/Laptop */
@media screen and (max-width: 1280px) {
    .login-container {
        width: 400px;
    }
}

/* Laptop */
@media screen and (max-width: 1024px) {
    .login-container {
        width: 380px;
    }
    
    .login-box {
        padding: 30px;
    }
}

/* Tablet Landscape */
@media screen and (max-width: 900px) {
    .login-container {
        width: 360px;
    }
}

/* Tablet Portrait */
@media screen and (max-width: 768px) {
    .login-container {
        width: 340px;
        padding: 20px;
    }
    
    .login-box {
        padding: 25px;
    }
    
    h2 {
        font-size: 1.8em;
    }
}

/* Large Mobile */
@media screen and (max-width: 576px) {
    .error {
        font-size: 13px;
        padding: 8px;
        margin: 8px 0;
        width: 100%;
    }
    .login-container {
        width: 320px;
        padding: 15px;
    }
    
    .login-box {
        padding: 20px;
    }
    
    h2 {
        font-size: 1.6em;
        margin-bottom: 20px;
    }
    
    .input-box {
        margin-bottom: 15px;
    }
    
    .remember-forgot {
        flex-direction: column;
        gap: 10px;
        align-items: center;
    }
}

/* Medium Mobile */
@media screen and (max-width: 480px) {
    .login-container {
        width: 300px;
        padding: 10px;
    }
    
    .login-box {
        padding: 15px;
    }
    
    h2 {
        font-size: 1.5em;
    }
    
    .input-box input {
        font-size: 14px;
    }
}

/* Small Mobile */
@media screen and (max-width: 375px) {
    .login-container {
        width: 280px;
    }
    
    h2 {
        font-size: 1.4em;
    }
}

/* Extra Small Mobile */
@media screen and (max-width: 320px) {
    .error {
        font-size: 12px;
        padding: 6px;
        margin: 6px 0;
    }
    .login-container {
        width: 260px;
    }
    
    .login-box {
        padding: 12px;
    }
    
    h2 {
        font-size: 1.3em;
    }
    
    .input-box {
        height: 45px;
    }
    
    .input-box input {
        font-size: 13px;
    }
    
    button {
        padding: 10px;
        font-size: 14px;
    }
    
    .register-link,
    .remember-forgot {
        font-size: 13px;
    }
}



/* messaggio di errore */
.error {
    width: 100%;
    text-align: center;
    margin: 10px 0;
    padding: 10px;
    border-radius: 5px;
    background-color: rgba(255, 0, 0, 0.1);
    color: #ff0000;
    font-size: 14px;
    animation: fadeIn 0.3s ease-in-out;
    border: 1px solid rgba(255, 0, 0, 0.2);
    box-sizing: border-box;
}

.dark-theme .error {
    background-color: rgba(255, 0, 0, 0.15);
    color: #ff4444;
    border-color: rgba(255, 0, 0, 0.3);
}

.error.hidden {
    display: none;
}