* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', sans-serif;
    background: #020617;
    color: white;
}

.header {
    background: rgba(15, 23, 42, 0.95);
    padding: 20px 8%;
    position: sticky;
    top: 0;
    z-index: 10;
    border-bottom: 1px solid #1e293b;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar h2 {
    color: #38bdf8;
}

.navbar a {
    color: white;
    text-decoration: none;
    background: #2563eb;
    padding: 10px 18px;
    border-radius: 10px;
}

.presentacion {
    min-height: 85vh;
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    padding: 60px 8%;
    gap: 40px;
    background: linear-gradient(135deg, #020617, #0f172a);
}

.texto h1 {
    font-size: 50px;
    margin-bottom: 10px;
}

.texto h3 {
    color: #38bdf8;
    font-size: 25px;
    margin-bottom: 20px;
}

.texto p {
    color: #cbd5e1;
    line-height: 1.7;
    margin-bottom: 30px;
}

.btn-principal {
    display: inline-block;
    background: linear-gradient(135deg, #2563eb, #06b6d4);
    color: white;
    padding: 15px 25px;
    border-radius: 12px;
    text-decoration: none;
    font-weight: bold;
}

.imagen-programador {
    display: flex;
    justify-content: center;
}

.codigo-card {
    width: 350px;
    padding: 30px;
    background: #0f172a;
    border: 1px solid #334155;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    font-family: monospace;
    color: #22c55e;
    font-size: 18px;
}

.sobre-mi,
.habilidades,
.subida,
.lista-documentos {
    padding: 60px 8%;
}

.sobre-mi h2,
.habilidades h2,
.subida h2,
.lista-documentos h2 {
    font-size: 32px;
    margin-bottom: 20px;
    color: #38bdf8;
}

.sobre-mi p {
    color: #cbd5e1;
    line-height: 1.8;
}

.cards {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 25px;
}

.card {
    background: #0f172a;
    padding: 25px;
    border-radius: 18px;
    border: 1px solid #1e293b;
    transition: 0.3s;
}

.card:hover {
    transform: translateY(-8px);
    border-color: #38bdf8;
}

.card h3 {
    color: #38bdf8;
    margin-bottom: 10px;
}

.card p {
    color: #cbd5e1;
}

.subida {
    background: #0f172a;
}

form {
    max-width: 650px;
    display: flex;
    flex-direction: column;
    gap: 18px;
}

input,
textarea {
    padding: 15px;
    border-radius: 12px;
    border: 1px solid #334155;
    background: #020617;
    color: white;
    outline: none;
}

textarea {
    height: 130px;
    resize: none;
}

button {
    background: linear-gradient(135deg, #2563eb, #06b6d4);
    color: white;
    border: none;
    padding: 15px;
    border-radius: 12px;
    cursor: pointer;
    font-weight: bold;
    font-size: 16px;
}

button:hover {
    opacity: 0.9;
}

#mensaje {
    margin-top: 20px;
    font-weight: bold;
}

.documentos {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 25px;
}

.documento {
    background: #0f172a;
    border: 1px solid #1e293b;
    padding: 25px;
    border-radius: 18px;
}

.documento h3 {
    color: #38bdf8;
    margin-bottom: 10px;
}

.documento p {
    color: #cbd5e1;
    margin-bottom: 10px;
}

.documento a {
    display: inline-block;
    background: #2563eb;
    color: white;
    text-decoration: none;
    padding: 10px 15px;
    border-radius: 10px;
    margin-top: 10px;
}

footer {
    text-align: center;
    padding: 25px;
    background: #020617;
    border-top: 1px solid #1e293b;
    color: #94a3b8;
}

@media (max-width: 900px) {
    .presentacion {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .cards,
    .documentos {
        grid-template-columns: 1fr;
    }

    .texto h1 {
        font-size: 36px;
    }
}