:root {
    --bg-color: #0f172a;
    --card-bg: rgba(30, 41, 59, 0.7);
    --border-color: rgba(255, 255, 255, 0.1);
    --accent-color: #fbbf24; /* Amber 400 */
    --accent-hover: #f59e0b; /* Amber 500 */
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --success-color: #4ade80; /* Emerald 400 */
    --error-color: #f87171; /* Red 400 */
}

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

body {
    background: radial-gradient(circle at top right, #1e293b, #0f172a);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 600px;
    animation: fadeIn 0.8s ease-out;
}

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

header {
    text-align: center;
    margin-bottom: 40px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 900;
    letter-spacing: -1px;
    background: linear-gradient(to right, #fff, var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.9rem;
    letter-spacing: 2px;
    margin-top: 5px;
}

.card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

/* Inputs */
.input-group {
    margin-bottom: 20px;
}

label {
    display: block;
    color: var(--accent-color);
    font-weight: 700;
    font-size: 0.8rem;
    text-transform: uppercase;
    margin-bottom: 8px;
}

input {
    width: 100%;
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 15px;
    color: white;
    font-size: 1.2rem;
    transition: all 0.3s;
}

input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(251, 191, 36, 0.2);
}

button {
    width: 100%;
    padding: 20px;
    border: none;
    border-radius: 16px;
    font-weight: 900;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

#btn-calcular {
    background: var(--accent-color);
    color: #000;
    box-shadow: 0 10px 15px -3px rgba(251, 191, 36, 0.3);
}

#btn-calcular:hover {
    background: var(--accent-hover);
    transform: scale(1.02);
}

#btn-calcular:active {
    transform: scale(0.98);
}

/* Resultados */
.result-card {
    border-left: 4px solid var(--accent-color);
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.result-total {
    border-top: 1px solid var(--border-color);
    padding-top: 15px;
    margin-top: 15px;
    display: flex;
    flex-direction: column;
}

.result-total .value {
    font-size: 2.8rem;
    font-weight: 900;
    color: var(--accent-color);
}

.info-tag {
    margin-top: 10px;
    font-weight: 700;
    font-size: 0.9rem;
    text-transform: uppercase;
}

/* Resumen */
.summary-section {
    text-align: center;
    padding: 20px;
}

.history-container h3 {
    color: var(--text-secondary);
    font-size: 0.8rem;
    text-transform: uppercase;
    margin-bottom: 10px;
}

.history-list {
    color: var(--text-secondary);
    font-style: italic;
    font-size: 0.9rem;
    margin-bottom: 20px;
    word-break: break-all;
}

.total-container {
    background: rgba(16, 185, 129, 0.1);
    padding: 20px;
    border-radius: 20px;
    margin-bottom: 20px;
}

#suma-total {
    font-size: 3rem;
    font-weight: 900;
    color: var(--success-color);
}

.btn-clear {
    background: transparent;
    color: var(--error-color);
    font-size: 0.8rem;
    padding: 10px;
    opacity: 0.7;
}

.btn-clear:hover {
    opacity: 1;
    text-decoration: underline;
}