@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700&display=swap');

html, body { height: 100%; }
main { flex: 1; }

:root {
  --bg: #f5f8ff;
  --card-bg: #ffffff;
  --muted: #6b7280;
  --text: #0b1220;
  --accent-1: #1f6feb;
  --accent-2: #1272d9;
  --accent-grad: linear-gradient(90deg,var(--accent-1),var(--accent-2));
  --panel-bg: #e9f0ff;
  --border: #dbe4f3;
  --shadow: 0 8px 25px rgba(20,40,80,0.06);
  --card-shadow: 0 6px 18px rgba(8,20,40,0.06);
}

body.dark {
  --bg: #0d1117;
  --card-bg: #0f1721;
  --muted: #9aa3b2;
  --text: #e6eef9;
  --accent-1: #3b82f6;
  --accent-2: #2b6fd6;
  --accent-grad: linear-gradient(90deg,var(--accent-1),var(--accent-2));
  --panel-bg: #0b1220;
  --border: #243146;
  --shadow: 0 10px 30px rgba(0,0,0,0.6);
  --card-shadow: 0 8px 28px rgba(0,0,0,0.6);
}

/*
=========================
   HEADER
=========================
*/
.page-header {
  width: 100%;
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
  padding: 14px 0;
  display: flex;
  justify-content: center;
  position: relative;
}

.header-inner {
  width: 100%;
  max-width: 1100px;
  padding: 0 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  min-width: 320px;
  gap: 12px;
}

/* --- LOGO (Left) --- */
.header-logo {
  display: flex;
  align-items: center;
  gap: 8px;
}
.header-logo img {
  height: 38px;
  width: 38px;
  border-radius: 8px;
  object-fit: cover;
}

/* --- TITLE + SUBTITLE (Center) --- */
.header-center {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  flex: 1;
  min-width: 180px;
}

.header-center h1 {
  margin: 0;
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent-2);
}

.header-center span {
  display: block;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--muted);
  line-height: 1.2;
}

/* --- THEME TOGGLE (Right) --- */
.header-right {
  display: flex;
  align-items: center;
  justify-content: flex-end;
}
.theme-toggle {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 50%;
  cursor: pointer;
  width: 38px;
  height: 38px;
  font-size: 18px;
  color: var(--text);
  box-shadow: var(--card-shadow);
  transition: transform 0.15s ease, background 0.2s ease, color 0.2s ease;
}
.theme-toggle:hover {
  transform: scale(1.06);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
  background: var(--bg);
  color: var(--text);
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  transition: background .25s ease, color .25s ease;
}

/*
=========================
   CALCULATOR CARD
=========================
*/
.calculator-container {
  width: 100%;
  display: flex;
  justify-content: center;
  padding: 20px;
}

.calculator-card {
  background: var(--panel-bg);
  border-radius: 16px;
  padding: 28px;
  width: 100%;
  max-width: 980px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: height 0.4s ease, padding 0.4s ease;
  margin: 0 16px;
}

.calculator-card.collapsed { height: 425px; } /* default height without results */
.calculator-card.expanded { height: auto; }

.calculator-card h2 {
  margin: 0 0 18px;
  font-size: 1.4rem;
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
}

/* ========================= Description Above Calculator ========================= */
.calculator-intro {
  text-align: center;       /* center the text */

  padding: 0 1rem;          /* padding for small screens */
  max-width: 700px;         /* limits line length for readability */
}

.calculator-description {
  font-size: 1.0rem;
  line-height: 1.6;
  word-wrap: break-word;    /* ensures text wraps properly on small screens */
}

/* ========================= Mobile Responsive ========================= */
@media (max-width: 480px) {
  .calculator-intro {
    margin: 1rem auto;
    padding: 0 0.5rem;
  }

  .calculator-description {
    font-size: 1rem;        /* slightly smaller on very small screens */
  }

  /* Ensure calculator grid stacks vertically */
  .calculator-grid {
    display: block;          /* stack sections vertically */
    gap: 1rem;               /* spacing between sections */
  }

  /* Make select dropdowns smaller and button full-width */
  .time-selectors select {
    width: 30%;              
    margin-bottom: 0.5rem;
  }

  .btn-primary {
    width: 100%;             /* button full width on mobile */
  }
}


/*
=========================
   GRID
=========================
*/
.calculator-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 26px;
}

.age-range h3,
.sleep-schedule h3 { margin:0 0 10px; font-size:1rem; color:var(--text); }

/*
=========================
   AGE BUTTONS
=========================
*/
.age-buttons {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 10px;
}

.age-buttons button {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  font-weight: 700;
  cursor: pointer;
  color: var(--text);
  transition: transform .12s ease, background .12s ease, color .12s ease;
  box-shadow: var(--card-shadow);
  text-align: center;
}

.age-buttons button span {
  display: block;
  font-weight: 500;
  font-size: 12px;
  margin-top: 4px;
  color: var(--muted);
  transition: color .2s ease;
}

.age-buttons button:hover { transform: translateY(-3px); }

.age-buttons button.active {
  background: var(--accent-grad);
  color: #fff;
  border-color: transparent;
}

.age-warning {
  text-align: center;
  color: #ff5c5c;
  font-size: 14px;
  margin-top: 8px;
  animation: fadeIn 0.3s ease;
}

.age-range.highlight {
  outline: 2px solid #ff5c5c;
  border-radius: 8px;
  transition: outline 0.2s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}


.age-buttons button.active span {
  color: #fff; /* ensure Months/Years text visible */
}

/* Schedule */
.sleep-schedule {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 18px;
  border: 1px solid var(--border);
}
.sleep-schedule h3 {
    margin: 0 0 8px;
    font-size: 1rem;
    color: var(--text);
}

/* Radio buttons */
.schedule-options {
    display: flex;
    flex-direction:
    column; gap: 10px;
    margin-bottom: 14px;
}

.radio-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 12px;
  border-radius: 10px;
  background: transparent;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all .12s ease;
  color: var(--text);
}
body:not(.dark) .radio-btn { background: rgba(255,255,255,0.85); }
.radio-btn.active {
    background: var(--accent-grad);
    color: black;
    box-shadow: 0 6px 18px rgba(18,70,160,0.12);
}

.radio-btn .label-text {
    font-weight: 600;
}

.radio-btn .icon {
    opacity: 0.95;
}

/* Time selectors */
.time-selectors {
    display: flex;
    gap: 10px;
    margin:z12px 0 8px;
}
select {
  flex: 1;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--card-bg);
  color: var(--text);
  font-weight: 600;
}

/* Calculate button */
.btn-primary {
  width: 100%;
  padding: 12px;
  border-radius: 12px;
  border: none;
  background: var(--accent-grad);
  color: white;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  margin-top: 6px;
  box-shadow: 0 8px 22px rgba(18,70,160,0.12);
  transition: transform .12s ease, opacity .2s ease;
}
.btn-primary:hover { transform: translateY(-2px); }

/* RESULTS area */
.results {
  margin-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  align-items: center;
  animation: fadeInUp .36s ease forwards;
}
.hidden { display: none !important; }

.result-row {
  display: flex;
  gap: 18px;
  width: 100%;
  flex-wrap: wrap;
  justify-content: center;
}
.result-card {
  width: 320px;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 10px 28px rgba(6, 18, 50, 0.12);
  background: linear-gradient(180deg, rgba(13,28,58,0.98), rgba(21,40,72,0.98));
  color: white;
  display: flex;
  flex-direction: column;
}
.result-top {
  padding: 18px;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
}
.result-top .col { display: flex; flex-direction: column; gap: 6px; }
.result-top .small { font-size: 13px; opacity: 0.9; }
.result-time { font-size: 28px; font-weight: 800; line-height: 1; letter-spacing: 0.5px; }
.dash { flex: 0 0 28px; display: flex; align-items: center; justify-content: center; color: rgba(255,255,255,0.22); }

.result-bottom {
  background: linear-gradient(90deg, rgba(0,0,0,0.12), rgba(255,255,255,0.02));
  padding: 10px 14px;
  text-align: center;
  font-weight: 700;
  font-size: 13px;
  color: #cfe6ff;
}

/* Go back */
.go-back-wrap { display: flex; justify-content: Center; margin-top: 10px; }
.go-back {
  background: transparent;
  border: none;
  color: var(--text);
  font-weight: 700;
  cursor: pointer;
  padding: 8px 12px;
  border-radius: 8px;
}
.go-back:hover { text-decoration: underline; }

/* Footer */
footer {
  width: 100%;
  margin-top: 40px;
  padding: 24px 0;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
  border-top: 1px solid var(--border);
  background: var(--card-bg);
  box-shadow: 0 -4px 12px rgba(0,0,0,0.05);
}

/* === FOOTER LINKS === */
.site-footer {
  text-align: center;
  padding: 18px 10px;
  font-size: 0.9rem;
  color: var(--muted);
  border-top: 1px solid var(--border);
  background: var(--card-bg);
  margin-top: 40px;
}

.site-footer a {
  color: var(--accent-2);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s ease, opacity 0.2s ease;
}

.site-footer a:hover {
  opacity: 0.8;
}

/* Responsive font sizing */
@media (max-width: 480px) {
  .site-footer {
    font-size: 0.8rem;
    padding: 14px 8px;
  }
}

/* Animations */
@keyframes fadeInUp { from{opacity:0;transform:translateY(10px);} to{opacity:1;transform:translateY(0);} }

/* Responsive */
@media (max-width: 900px) {
  .calculator-grid { grid-template-columns: 1fr; }
  .age-buttons { grid-template-columns: repeat(4,1fr); }
  .result-card { width: 100%; max-width: 520px; }
}

/*
=========================
   RESPONSIVE MOBILE
=========================
*/
@media (max-width: 768px) {
  .calculator-grid { 
    grid-template-columns: 1fr; 
    gap:16px; 
    min-height: 0px; /* Minimum height for mobile */
  }
  .age-buttons { grid-template-columns: repeat(4,1fr); }
  .calculator-card { 
    padding:16px; 
    min-height: 650px; /* Minimum card height on mobile */
    transition: all .3s ease;
  }
  .result-card { width:100%; max-width:100%; }
}

/* ==============================
   Tablet layout adjustments
   ============================== */
@media (min-width: 768) and (max-width: 1024px) {
  .calculator-grid {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
  }

  .age-range,
  .sleep-schedule {
    width: 100%;
  }

  .sleep-schedule {
    margin-top: 1rem;
  }

  .calculator-card {
    max-width: 700px;
    width: 90%;
    padding: 1.5rem;
  }

  .time-selectors {
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
  }

  .time-selectors select {
    width: 30%;
    min-width: 80px;
  }

  .schedule-options {
    flex-direction: row;
    justify-content: space-around;
    flex-wrap: wrap;
  }
}


/* Responsive footer font sizing */
@media (max-width: 480px) {
  .site-footer {
    font-size: 0.8rem;
    padding: 14px 8px;
  }
}

/* Recommended Sleep Chart link styling */
.open-chart-link {
  text-align: Right;
  margin-top: 10px;
}

.open-chart-link a {
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
  transition: color 0.3s;
}

.open-chart-link a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

/* Key Takeaways box */
.takeaways-box {
  background: var(--accent-light);
  color: var(--text);
  border-radius: 12px;
  padding: 20px 24px;
  margin-top: 24px;
  text-align: left;
}

.takeaways-box h3 {
  color: var(--text-strong);
  font-size: 18px;
  margin-bottom: 10px;
}

.takeaways-box ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

.takeaways-box li {
  position: relative;
  padding-left: 20px;
  margin-bottom: 8px;
  line-height: 1.5;
}

.takeaways-box li::before {
  content: "•";
  color: var(--accent);
  position: absolute;
  left: 0;
  top: 0;
}

.takeaways-box a {
  color: var(--accent-hover);
  text-decoration: none;
}

.takeaways-box a:hover {
  text-decoration: underline;
}

/* Dark mode adjustment */
body.dark .takeaways-box {
  background: var(--panel-bg);
}

.mobile-ad {
  text-align: center;
  margin: 16px auto;
  width: 100%;
  max-width: 360px;
}

.hidden {
  display: none !important;
}

/* Hide ads on desktop */
@media (min-width: 769px) {
  .mobile-ad {
    display: none !important;
  }
}