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

/* BODY */
body {
  font-family: Arial, sans-serif;
  background: radial-gradient(circle at top, #dc6bc9, #5e5ee7);
  overflow-x: hidden;
}

/* HEADER */
.top-header {
  background: #ffffff;
  border-bottom: 1px solid #2b2929;
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px;
}

.header-inner h1 {
  margin-bottom: 15px;
  font-size: 1.8rem;
  font-weight: 700;
  color: rgb(34, 34, 129);
}

/* NAV */
.sub-nav ul {
  list-style: none;
  display: flex;
  gap: 28px;
  padding: 0;
  margin: 8px 0 0;
  flex-wrap: wrap;
}

.sub-nav a {
  text-decoration: none;
  color: #374151;
  font-size: 0.95rem;
  padding-bottom: 8px;
  position: relative;
}

.sub-nav a:hover {
  font-weight: 800;
  color: black;
}

.sub-nav li.active a {
  color: #1d4ed8;
  font-weight: 600;
}

.sub-nav li.active a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 3px;
  background: #1d4ed8;
  border-radius: 2px;
}

/* BUTTONS */
.button {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  flex-wrap: wrap;
}

button {
  background-color: #1d4ed8;
  color: white;
  border: 1px solid #a5a6a8;
  padding: 10px 14px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.4s ease;
}

button:hover {
  background-color: #2f4f95;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.25);
}

button:active {
  transform: translateY(2px);
}

/* MAIN GRID */
.app-container {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  max-width: 1200px;
  width: 100%;
  padding: 40px;
  gap: 50px;
  margin: 50px auto;
  border-radius: 15px;
}

/* LEFT & RIGHT */
.left, .right {
  background: white;
  padding: 24px;
  border-radius: 14px;
  border: 1px solid #171616;
}

/* INPUTS */
.budget-form input,
.expense-form input {
  width: 100%;
  padding: 10px;
  margin-bottom: 12px;
  border: 2px solid transparent;
  border-radius: 6px;
  font-size: 1rem;
  transition: 0.3s;
}

.budget-form input:focus,
.expense-form input:focus {
  border-color: rgb(150, 65, 79);
  outline: none;
}

/* EXPENSE HISTORY */
.expense-history {
  display: flex;
  padding: 10px;
}

.expense-history p {
  flex: 1;
  font-size: 1.2rem;
  margin: 0 10px;
}

/* TABS */
.tab {
  display: none;
}

.tab.active {
  display: block;
}

/* PAGE CARD */
.page-card {
  background: rgb(232, 127, 232);
  padding: 32px;
  width: 100%;
  max-width: 500px;
  height: 50vh;
  margin: 50px auto;
  border-radius: 15px;
  border: 2px solid rgba(35, 34, 34, 0.3);
  box-shadow: 0 0px 10px silver;
}

/* ========================= */
/* 📱 MOBILE (0–768px) */
/* ========================= */

@media (max-width: 768px) {

  .header-inner {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .sub-nav ul {
    justify-content: center;
    gap: 15px;
  }

  .button {
    justify-content: center;
    margin-top: 10px;
  }

  .app-container {
    grid-template-columns: 1fr;
    padding: 15px;      /* FIXED */
    gap: 20px;          /* FIXED */
    margin: 20px auto;
  }

  .expense-history {
    flex-direction: column;   /* FIXED */
    gap: 10px;
  }

  .expense-history p {
    font-size: 1rem;
    margin: 0;
  }

  .page-card {
    max-width: 100%;
    padding: 20px;
    margin: 20px auto;
  }
}

/* ========================= */
/* 📲 TABLET (768–1024px) */
/* ========================= */

@media (min-width: 768px) and (max-width: 1024px) {

  .app-container {
    grid-template-columns: 1fr 1fr;
    padding: 25px;
    gap: 30px;
  }

  .page-card {
    max-width: 500px;
  }
}

/* ========================= */
/* 💻 LAPTOP (1024px+) */
/* ========================= */

@media (min-width: 1024px) {

  .app-container {
    grid-template-columns: 1fr 1.2fr;
  }

  .page-card {
    max-width: 500px;
  }
}