:root {
    --bg-primary: #121212;
    --bg-secondary: #0e0e0e;
    --bg-card: #1e1e1e;
    --bg-input: #2a2a2a;
    --text-primary: #ececec;
    --text-secondary: #a3a3a3;
    --text-muted: #6b6b6b;
    --accent: #10b981;
    --accent-hover: #059669;
    --accent-light: #34d399;
    --accent-glow: rgba(16, 185, 129, 0.2);
    --border: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(16, 185, 129, 0.3);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.25);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.35);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.45);
    --btn-gradient: linear-gradient(135deg, #059669, #34d399);
}

[data-theme="light"] {
    --bg-primary: #f7f7f7;
    --bg-secondary: #eeeeee;
    --bg-card: #ffffff;
    --bg-input: #f0f0f0;
    --text-primary: #1a1a1a;
    --text-secondary: #525252;
    --text-muted: #8a8a8a;
    --accent: #059669;
    --accent-hover: #047857;
    --accent-light: #10b981;
    --accent-glow: rgba(5, 150, 105, 0.12);
    --border: rgba(0, 0, 0, 0.1);
    --border-hover: rgba(5, 150, 105, 0.25);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.07);
    --btn-gradient: linear-gradient(135deg, #047857, #10b981);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    text-decoration: none;
    font-family: 'Roboto', sans-serif;
}

body {
    background: linear-gradient(160deg, #0e0e0e 0%, #121212 50%, #0f1f18 100%);
    min-height: 100vh;
    transition: background 0.4s ease;
}

[data-theme="light"] body {
    background: linear-gradient(160deg, #f7f7f7 0%, #f0fdf4 100%);
}

main {
    width: 100%;
    padding: 20px;
    margin: auto;
    margin-top: 80px;
    animation: fadeInUp 0.6s ease-out;
}

.contenedor__todo {
    width: 100%;
    max-width: 800px;
    margin: auto;
    position: relative;
}

.caja__trasera {
    width: 100%;
    padding: 10px 20px;
    display: flex;
    justify-content: center;
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    background: rgba(30, 30, 30, 0.5);
    border-radius: 20px;
    border: 1px solid var(--border);
}

.caja__trasera div {
    margin: 100px 40px;
    color: var(--text-primary);
    transition: all 500ms;
}

.caja__trasera div p,
.caja__trasera button {
    margin-top: 30px;
}

.caja__trasera div h3 {
    font-weight: 400;
    font-size: 26px;
    color: #ffffff;
}

.caja__trasera div p {
    font-size: 16px;
    font-weight: 300;
    color: var(--text-secondary);
}

.caja__trasera button {
    padding: 10px 40px;
    border: 2px solid rgba(255, 255, 255, 0.5);
    font-size: 14px;
    background: transparent;
    font-weight: 600;
    cursor: pointer;
    color: white;
    outline: none;
    border-radius: 10px;
    transition: all 300ms;
}

.caja__trasera button:hover {
    background: #fff;
    color: var(--accent-hover);
    box-shadow: 0 0 20px var(--accent-glow);
}

/* Login/Register Forms */
.contenedor__login-register {
    display: flex;
    align-items: center;
    width: 100%;
    max-width: 380px;
    position: relative;
    top: -185px;
    left: 10px;
    transition: left 500ms cubic-bezier(0.175, 0.885, 0.320, 1.275);
}

.contenedor__login-register form {
    width: 100%;
    padding: 50px 24px;
    background: rgba(18, 18, 18, 0.85);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    position: absolute;
    border-radius: 20px;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg), 0 0 60px rgba(16, 185, 129, 0.06);
    animation: fadeInUp 0.5s ease-out;
}

.contenedor__login-register form h2 {
    font-size: 28px;
    text-align: center;
    margin-bottom: 24px;
    color: var(--accent);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.contenedor__login-register form h2 i {
    font-size: 24px;
    color: var(--accent-light);
}

.input-group {
    display: flex;
    align-items: center;
    margin-top: 20px;
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: 10px;
    transition: border-color 300ms, box-shadow 300ms;
    overflow: hidden;
}

.input-group:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 8px var(--accent-glow);
}

.input-group i {
    padding: 0 14px;
    color: var(--text-muted);
    font-size: 16px;
    flex-shrink: 0;
}

.input-group:focus-within i {
    color: var(--accent);
}

.input-group input {
    flex: 1;
    padding: 12px 14px 12px 0;
    border: none;
    background: transparent;
    font-size: 16px;
    outline: none;
    color: var(--text-primary);
    width: 100%;
}

.input-group input::placeholder {
    color: var(--text-muted);
}

.contenedor__login-register form input:not(.input-group input) {
    width: 100%;
    margin-top: 20px;
    padding: 12px 14px;
    border: 1px solid var(--border);
    background: var(--bg-input);
    font-size: 16px;
    outline: none;
    color: var(--text-primary);
    border-radius: 10px;
    transition: border-color 300ms, box-shadow 300ms;
}

.contenedor__login-register form input:not(.input-group input)::placeholder {
    color: var(--text-muted);
}

.contenedor__login-register form input:not(.input-group input):focus {
    border-color: var(--accent);
    box-shadow: 0 0 8px var(--accent-glow);
}

.contenedor__login-register form button {
    padding: 12px 40px;
    margin-top: 30px;
    border: none;
    font-size: 14px;
    background: var(--btn-gradient);
    font-weight: 600;
    cursor: pointer;
    color: white;
    outline: none;
    border-radius: 10px;
    transition: all 300ms;
    box-shadow: 0 4px 15px rgba(5, 150, 105, 0.2);
    width: 100%;
}

.contenedor__login-register form button:hover {
    box-shadow: 0 4px 25px rgba(16, 185, 129, 0.35);
    transform: translateY(-1px);
}

.formulario__login {
    opacity: 1;
    display: block;
}

.formulario__register {
    display: none;
}

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

@media screen and (max-width: 850px) {
    main {
        margin-top: 50px;
    }

    .caja__trasera {
        max-width: 350px;
        height: 300px;
        flex-direction: column;
        margin: auto;
    }

    .caja__trasera div {
        margin: 0px;
        position: absolute;
    }

    .contenedor__login-register {
        top: -10px;
        left: -5px;
        margin: auto;
    }

    .contenedor__login-register form {
        position: relative;
    }
}