:root {
    --bg-color: #f8fafc;
    --card-bg: rgba(255, 255, 255, 0.8);
    --text-main: #0f172a;
    --text-muted: #64748b;
    --accent: #0f172a;
    --accent-hover: #334155;
    --error: #ef4444;
    --success: #22c55e;
    --border: #e2e8f0;
    --radius: 16px;
    --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    background-image: radial-gradient(at 0% 0%, rgba(226, 232, 240, 0.5) 0, transparent 50%),
                      radial-gradient(at 100% 0%, rgba(226, 232, 240, 0.5) 0, transparent 50%);
    color: var(--text-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 60px 24px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 60px;
    animation: fadeInDown 0.6s ease-out;
}

header h1 {
    font-weight: 700;
    letter-spacing: -1.5px;
    font-size: 1.75rem;
    color: var(--text-main);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 20px;
}

.user-status {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 500;
    background: white;
    padding: 6px 12px;
    border-radius: 20px;
    border: 1px solid var(--border);
}

.logout-btn {
    background: none;
    border: 1px solid var(--border);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.75rem;
    text-transform: uppercase;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: 600;
    color: var(--text-muted);
}

.logout-btn:hover {
    background: var(--text-main);
    color: white;
    border-color: var(--text-main);
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 32px;
    margin-bottom: 60px;
}

.card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--radius);
    padding: 32px;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    animation: fadeInUp 0.6s ease-out;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.card h2 {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--text-muted);
    margin-bottom: 24px;
    font-weight: 700;
}

/* Budget Card */
.budget-value {
    display: flex;
    align-items: baseline;
    gap: 8px;
    margin-bottom: 20px;
}

.budget-value #balance {
    font-size: 3.5rem;
    font-weight: 300;
    letter-spacing: -3px;
    color: var(--text-main);
}

.budget-value .currency {
    font-size: 1.1rem;
    color: var(--text-muted);
    font-weight: 600;
}

.progress-container {
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 16px;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--accent), #64748b);
    width: 0%;
    transition: width 1s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.budget-detail {
    font-size: 0.85rem;
    color: var(--text-muted);
    display: flex;
    justify-content: space-between;
}

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

.input-group label {
    display: block;
    font-size: 0.65rem;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 8px;
    font-weight: 700;
    letter-spacing: 0.05em;
}

.input-group input, .input-group select {
    width: 100%;
    padding: 12px 16px;
    background: white;
    border: 1px solid var(--border);
    border-radius: 10px;
    font-family: inherit;
    font-size: 0.95rem;
    transition: all 0.2s;
    color: var(--text-main);
}

.input-group input:focus, .input-group select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(15, 23, 42, 0.1);
}

#submit-btn {
    width: 100%;
    padding: 14px;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 10px;
    font-weight: 600;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 4px 6px -1px rgba(15, 23, 42, 0.2);
}

#submit-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

#submit-btn:active {
    transform: translateY(0);
}

#submit-btn:disabled {
    background: var(--text-muted);
    cursor: not-allowed;
}

/* History Section */
.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    gap: 20px;
    animation: fadeInUp 0.8s ease-out;
}

.history-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.5px;
}

.search-container {
    position: relative;
    flex: 1;
    max-width: 400px;
}

.search-input {
    width: 100%;
    padding: 10px 16px;
    padding-left: 40px;
    background: white;
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.85rem;
    transition: all 0.2s;
}

.search-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(15, 23, 42, 0.05);
}

.search-icon {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    pointer-events: none;
}

.transactions-grid {
    display: grid;
    gap: 12px;
}

.tx-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    background: var(--card-bg);
    backdrop-filter: blur(8px);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: all 0.2s;
    animation: slideIn 0.4s ease-out forwards;
    opacity: 0;
}

.tx-item:hover {
    background: white;
    transform: scale(1.01);
    box-shadow: var(--shadow);
}

.tx-info .tx-desc {
    display: block;
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-main);
}

.tx-info .tx-meta {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.tx-right {
    display: flex;
    align-items: center;
    gap: 16px;
}

.tx-amount {
    font-weight: 600;
    color: var(--text-main);
}

.delete-tx-btn {
    background: none;
    border: none;
    color: #cbd5e1;
    cursor: pointer;
    transition: color 0.2s;
    font-size: 1.2rem;
    padding: 4px;
}

.delete-tx-btn:hover {
    color: var(--error);
}

.empty-state {
    text-align: center;
    padding: 60px;
    color: var(--text-muted);
    font-weight: 300;
    font-size: 1rem;
}

/* Auth Screen */
.auth-card {
    background: white;
    padding: 48px;
    border-radius: 32px;
    width: 100%;
    max-width: 420px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.1);
    text-align: center;
    animation: zoomIn 0.4s ease-out;
}

.auth-header {
    margin-bottom: 32px;
}

.auth-header h1 {
    font-size: 2.25rem;
    font-weight: 700;
    letter-spacing: -1.5px;
    margin-bottom: 8px;
}

.auth-header p {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 400;
}

.auth-footer {
    margin-top: 24px;
}

.auth-footer button {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 0.8rem;
    cursor: pointer;
    transition: color 0.2s;
    text-decoration: none;
}

.auth-footer button:hover {
    color: var(--text-main);
    text-decoration: underline;
}

/* Overlays */
.overlay {
    position: fixed;
    inset: 0;
    background: var(--bg-color);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.loader-content {
    text-align: center;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin: 0 auto 16px;
}

@keyframes spin { to { transform: rotate(360deg); } }

.error-banner {
    position: fixed;
    top: 24px;
    right: 24px;
    background: var(--error);
    color: white;
    padding: 16px 24px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 12px;
    z-index: 2000;
    box-shadow: 0 10px 15px -3px rgba(239, 68, 68, 0.4);
    animation: slideIn 0.3s ease-out;
}

.error-banner button {
    background: none;
    border: none;
    color: white;
    font-size: 1.2rem;
    cursor: pointer;
    opacity: 0.7;
}

@keyframes slideIn {
    from { transform: translateX(120%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

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

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

@keyframes zoomIn {
    from { opacity: 0; transform: scale(0.9); }
    to { opacity: 1; transform: scale(1); }
}

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

.hidden { display: none !important; }